Johnson Controls LX Series User Manual

LX Series Unit Ventilator Controller

User’s Guide

Code No. LIT-12011486

Issued June 22, 2009

Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .9

Sensor Configuration Wizard . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10

Control Features . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10

LONMARK Functional Profile. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11

Units in LONWORKS Networks . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .14

Language Selection. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15

Selecting a Measurement System or Selecting a Language . . . . . . . . . . . . . . . . . . . . . 16

Unit Ventilator Controller Installation Overview. . . . . . . . . . . . . . . . . . . . . . . . . . . . 19

Inputs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19

10k Ohm or Digital Input . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20

Analog Inputs. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21

4 to 20 mA Analog Input, Externally Supplied . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21

Sensors and Switches. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22

Auxiliary Alarm Input . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22

Bypass Contact Input. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22

Level Input . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22

Discharge Temperature Input . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22

Economizer Enable Input. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22

Emergency Contact Input . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22

Fan Speed Selector Input . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22

Fan State Input . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23

Mixed Air Temperature Input . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23

Mode Selector . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23

Occupancy Input . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24

Outdoor Enthalpy Input . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24

1LX Series Unit Ventilator Controller User’s Guide

Outdoor Humidity Input . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24

Outdoor Temperature Input . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24

Return Air Temperature Input . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24

Setpoint Offset Input . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24

Space Enthalpy Input. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25

Space Humidity Input . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25

Space Temperature Input . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25

Water Temperature Input. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25

Window Contact Input . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26

Outputs. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27

Analog Output . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27

Analog Output Protection. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27

Digital Outputs. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27

Staged Outputs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29

Output Selections . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29

Fan Speed 1–3 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29

Heating Outputs 1–4 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29

Cooling Outputs 1–4 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29

Reversing Valve. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29

Humidifier and Dehumidifier Outputs. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30

Minimum Fresh Air Enable (MIN_FRESH_AIR_ENABLE) . . . . . . . . . . . . . . . . . . . . . . . . . 30

Economizer Enable . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30

Heat Valve ON-OFF. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30

Cool Valve ON-OFF. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30

Heat Cool Valve ON-OFF . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30

Heat Valve Open or Close. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30

Cooling Valve Open or Close. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30

Heat Cool Valve Open or Close. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30

Fan Speed Modulate (FAN_SPEED_MOD) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30

Heating Modulate (HEATING_MOD). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31

LX Series Unit Ventilator Controller User’s Guide2

Heating or Cooling Valve Modulate (HEATING_VALVE_MOD) (COOLING_VALVE_MOD)31

Fresh Air Damper Modulate (FRESH_AIR_DAMPER_MOD) . . . . . . . . . . . . . . . . . . . . . . . 31

Fresh Air Damper Open or Close . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31

Mode Selection. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31

Network Variables Used for Mode Selection. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31

Occupied Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32

Starting Occupied Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33

Ending Occupied Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33

Unoccupied Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33

Starting Unoccupied Mode. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33

Ending Unoccupied Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34

Bypass Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34

Starting Bypass Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 35

Ending Bypass Mode. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 35

Standby Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 35

Starting Standby Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 35

Ending Standby Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36

Slave Mode. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36

State Selection and Description. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36

Supervisory Control and Scheduling. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36

Calculating the Space Temperature Setpoint . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 37

The Effect of nviSetPoint on the Active Setpoints . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 37

The Effect of a Setpoint Offset on the Active Setpoints. . . . . . . . . . . . . . . . . . . . . . . . . . . . 38

Ventilation. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .38

Ventilation Separate from Free Cooling. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 38

Control of the Fresh Air Intake. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 40

Outputs That Control the Fresh Air Damper . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 40

Humidity Control . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 41

Cooling State . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 42

Free Cooling . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 42

LX Series Unit Ventilator Controller User’s Guide 3

When Free Cooling is Used. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 43

Mechanical Cooling . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 43

Cooling Demand . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 44

Cooling Output Sequence . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 44

Ending the Cooling State. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 44

Heating States . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 45

Heating Demand . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 46

Heating Output Sequence . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 46

Cooling Outputs Used to Heat. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 46

Ending the Heating State. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 46

Night Purge. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 46

Morning Warm-up State . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 47

Using Night Purge and Morning Warm-up with DCV . . . . . . . . . . . . . . . . . . . . . . . . . . . 47

Fan Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 47

Terminal Load . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 48

Heating Terminal Load . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 49

Cooling Terminal Load . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 50

Networking Operations. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 51

Slave Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 51

Load Shedding. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 51

Setting-up Network Connections. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 51

Network Outputs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 52

Optimum Start . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 53

Requirements for Optimum Start. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 53

Emergency Operation. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 54

Emergency Initiation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 55

Normal Operation. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 55

The PID Loop. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 55

Proportional . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 56

Integral . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 56

LX Series Unit Ventilator Controller User’s Guide4

Gain . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 57

Time. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 57

How It Is Used . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 57

Derivative . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 58

Gain . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 58

Time. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 59

Deadband . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 59

Alarm Operation. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 60

Alarm Features. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 61

Alarm Types . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 62

Alarm Procedure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 62

Heartbeat Alarms. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 63

Disconnect Alarms. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 65

Emergency Mode Alarms. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 65

User-Set Alarms. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 65

Setting up the Unit Ventilator Controller. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 66

Persistent Network Variables . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 66

Setting Units. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 67

Input Configuration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 67

Output Configuration. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 68

Output Signal Types . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 69

Configuring an Output. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 69

Configuring an Output Represented as a Functional Block. . . . . . . . . . . . . . . . . . . . . . . . . 71

Heating-Cooling Configuration. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 72

Optimum Start . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 73

Fan-Valve Configuration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 74

PID Configuration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 76

Alarm Configuration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 77

Space and Return Temperatures and Humidity . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 77

Levels . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 78

LX Series Unit Ventilator Controller User’s Guide 5

Discharge Temperature and Auxiliary Alarm . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 78

Mixed Air Temperature . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 78

Fan Alarm . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 78

General Settings Configuration. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 79

Radiation Heating . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 80

Options Configuration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 81

Optimum Start . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 81

Frost Protection. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 82

Humidity Control . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 82

Network Input Configuration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 83

Heartbeat Alarms. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 83

Network Output Configuration. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 84

Object Manage. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 85

Object Status . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 85

Communication Failure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 87

Electrical Fault . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 87

Out of Limits. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 87

Disabled. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 87

In Alarm . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 87

In Override. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 87

Out of Service . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 87

Network Variables. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 87

nviApplicMode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 88

nviCO2 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 88

nviDischargeTemp. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 88

nviEconoEnable. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 88

nviEmergCmd. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 89

nviExtCmdOutputx . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 89

nviFanSpeedCmd. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 89

nviFanState. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 89

LX Series Unit Ventilator Controller User’s Guide6

nviHotWater . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 90

nviMixedAirTemp. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 90

nviOccCmd and nviOccManCmd . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 90

nviOutdoorEnth . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 90

nviOutdoorRH . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 90

nviOutdoorTemp . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 91

nviReturnTemp. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 91

nviSetPoint. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 91

nviSetPointOffset. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 91

nviShedding . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 91

nviSlave . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 91

nviSpaceEnth. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 91

nviSpaceRH . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 92

nviSpaceTemp . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 92

nviWaterTemp . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 92

nvoCtrlOutputx. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 92

nvoDischargeSetPt . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 92

nvoEconoEnable . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 92

nvoEffectSetPt . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 92

nvoFanSpeed . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 93

nvoHwInputx . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 93

nvoOccState. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 93

nvoUValarm. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 93

nvoUVstate. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 95

nvoSpaceTemp . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 96

nvoTerminalLoad. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 97

nvoUnitStatus. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 97

Standard Network Variable Types (SNVTs). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 98

SNVT_hvac_emerg (103). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 98

SNVT_hvac_mode (108) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 98

LX Series Unit Ventilator Controller User’s Guide 7

SNVT_hvac_status (112). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 99

Alarm State. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 102

SNVT_lev_percent (81) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 103

SNVT_occupancy (109) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 103

SNVT_ppm (29) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 104

SNVT_switch (95). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 104

Switch Definition . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 104

SNVT_temp_p (105) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 106

SNVT_tod_event (128) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 106

LX Series Unit Ventilator Controller User’s Guide8

LX Series Unit Ventilator Controller

User's Guide

Introduction

The LX Series Unit Ventilator Controller (UVC) seamlessly integrates into a LONWORKS® network for the control of almost any Unit Ventilator Controller due to its wide range of output types and LONMARK® certification.

The LX Series Unit Ventilator Controller controls the following equipment:

• up to four stages of mechanical heating or cooling

• modulating heating or cooling valves

• reversing valves for application requiring a heat pump

• floating valves for heating or cooling

• unit ventilator with or without an economizer

• up to three fan speeds or variable speed fans

• humidifier and dehumidifier

• an economizer that requires analog, digital, or Pulse Width Modulation (PWM) control signals

The UVC has five digital outputs supplying 1.0 ampere at 24 VAC. These outputs produce digital or PWM signals.

There are also two tri-mode analog outputs on the circuit board. These outputs provide the following signals:

• linear signals over a 0 to 10 VDC range

• 10 VDC digital or PWM signals

• digital signals of 60 mA at 12 VDC

The controller has six inputs, each capable of one of 21 possible input types. Inputs have 12-bit resolution and are configured completely by software.

For easy maintenance and installation, the controller is equipped with plug-in connectors that accept flat cable or wires. The controller uses a TP/FT-10 78 kbps network configuration.

The information in this guide helps you to set up the UVC, understand the operation of the UVC, and troubleshoot problems of the device. Information is organized to follow the UVC configuration wizard menu.

LX Series Unit Ventilator Controller User's Guide 9

Sensor Configuration Wizard

The UVC incorporates the sensor configuration wizard. The wizard provides powerful and simple configuration tools for the hardware inputs. You can select the digital or analog inputs through the software, which means there are no circuit board jumpers to move.

Analog input signal types - resistive, voltage, current - are selected in software without hardware jumpers. Built-in conversion tables are provided for a large number of thermistors or other sensor types. You can easily create custom conversion tables by setting the offset, minimum, and maximum values in one dialog box for the input.

The sensor configuration wizard also provides direct access to network properties of the analog or digital input including the Standard Network Variable Type (SNVT), Heartbeat, Send on Delta, Override, Default Value, and Throttle settings. All input features are conveniently located on one screen, which avoids the hassle of switching back and forth between screens to fully configure an input. In addition, the wizard provides warnings of configuration errors as they occur, enabling you to correct mistakes quickly.

Shown by the LX-UVL wizard view in FX Workbench, the sensor configuration wizard exists as a separate object. A separate functional block represents each hardware input. To configure an input, select the hardware input on the left side of the LX-UVL wizard view of the device and click the Launch button. The sensor configuration wizard allows you to control network inputs not directly controlled by the Unit Ventilator Controller.

Control Features

The Unit Ventilator Controller provides Proportional plus Integral plus Derivative (PID) loops for advanced control of humidity, discharge temperature, and space temperature. Each PID loop has an individual, configurable deadpan. In addition, each PID loop provides gain and time adjustment for the integral and derivative terms, and gain adjustment for the proportional term.

Whereas space temperature control is done with a PI loop only , the presence of the derivative term adds the ability to precisely adjust space temperature control to provide better comfort and increased savings.

The PID loop is especially useful in controlling the CO2 concentration, since this can vary quickly and greatly as individuals enter and exit meeting rooms, and work

areas. The quick response of the PID loop also maintains duct pressure within acceptable limits.

Humidification and dehumidification sequences provide the UVC with the ability to maintain the space humidity at the desired level. The Unit Ventilator Controller also provides advanced control features often associated with air handlers. These features include Optimum Start and load shedding.

LX Series Unit Ventilator Controller User's Guide10

The Optimum Start function maintains statistics that enable the Unit Ventilator Controller to predict the warm-up or cool-down time period needed to make the building ready for occupancy. The precise Optimum Start period is calculated every day using the current outdoor air temperature.

LONMARK Functional Profile

The LX Series Unit Ventilator Controller uses LONWORKS network protocol and is LONMARK certified for interoperability on any LONWORKS network. The Unit Ventilator Controller is set up through its own configuration wizard and the Sensor configuration wizard. You can use FX Workbench or any other network management tool to install the device onto the network and bind variable connections.

Figure 1 shows that the Unit Ventilator Controller meets the LONMARK standard by providing the network variable inputs, network variable outputs, and configuration properties specified by the profile. In addition, the Unit Ventilator Controller provides many extra network variable inputs and outputs. These extra network variables provide a greater flexibility and number of functions than required in the LONMARK profile.

For example, you can use network input nviSlave, to slave the UVC to another unit, whereas network output nvoUnitStatus, enables the UVC to act as the master node. The Unit Ventilator Controller has network inputs that permit the use of outside enthalpy sensors and space enthalpy sensors. These inputs provide better calculation of the cooling or heating effect of the outside air upon the conditioned space.

The input object has conversion tables and hardware properties present as configuration properties in the area marked Manufacturer Configuration Properties. By choosing from a list of standard thermistors, you can select different conversion properties. The conversion tables configuration property allows you to create your own custom tables. Hardware properties, located in the same area, allow you to modify your input from the software object.

LX Series Unit Ventilator Controller User's Guide 11

nviSpaceTemp

SNVT_ temp_p

nviApplicMode

SNVT_ hvac_ mode

nviSetP tOffset

SNVT_ temp_p

nviOutdoorTem p

SNVT_ temp_p

nviOutdoorR H

SNVT_lev_ percent

nviSpaceRH

SNV T_ lev_ percent

nviCO2

SNVT_ ppm

nviEmergCmd

SNV T_ hvac_ emerg

Occ. Temperature Set Points (mandatory)

nviEconoEnable

SNVT_ switch

nviFanState

SNVT_ switch

nviFanSpeedCmd

SNVT_ switch

nv iM ixed A ir Te m p

SNVT_ temp_p

nviOccManCmd

SNVT_ occupancy

nviReturnTemp

SNVT_ temp_p nviShedding

SNVT_ switch

nviS lav e

SNVT_ hvac_ status

nviSupplyTem p

SNVT_ temp_p

nviOccCm d

SNV T_ tod_event

nviSpaceEnth SNV T_ enthalpy

nviOutdoorE nth

SNVT_ enthalpy

nviWaterTemp SNVT_ temp_p

nviHotWater SNVT_ switch

nviSetpoint

SNVT_ temp_p

Manufacturer Configuration Properties

LX-UVL- 1 Unit Ventilator

Object Type # 808 0

Mandatory

Netw ork

Variables

Optional Netw ork

Variables

C o n fig ura t io n P r o p e r tie s

Maximum S end Time (mandatory)

Minimum Send Time (optional)

Maximum R eceive Time ( optional)

CO 2 limit (optional)

Local Bypass Time (optional)

Manufacturer

Netw ork

Variables

Please see the m anual for details.

Wizard for configuration provided.

nvoSpaceTemp

SNVT_ temp_p

nv oU n itSta tu s

SNVT_ hvac_ status

nv oE ffe c tS e tp t

SNVT_ temp_p

nvoEconoEnable

SNVT_ switch

nvoFanSpeed

SNVT_ switch nv oO ccS ta te

SNVT_ occupancy

nvoTerminalLoad

SNV T_ lev_ percent

nvoCtrlO utput1

SNVT_ switch

. . .

nvoCtrlO utput7

SNVT_ switch

nvoSupplySetPt

SNVT_ temp_p

Figure 1: LX Series Unit Ventilator Controller:

ONMARK Functional Profile

LX Series Unit Ventilator Controller User's Guide12

Figure 2 shows the Unit Ventilator Controller input object and the output object.

6 x LX-UVL-1 Hardware Input

Object Type #1

Mandatory

Network

Variables

Configuration Properties

Offset ( optional)

Maximum Range (optional)

Minimum Range (optional)

Minimum Send Delta (optional)

Maximum Send Time (optional)

Minimum Send Time (optional)

Override Value (optional)

Manufacturer Configuration Properties

Object M ajo r Ve rsion Object Minor Version

Input Signal Conditioning

Hardware Properties

Translation Table

Default Value

nvoHwInput1

SNVT _xxx

nviExtCmdOutput1

SNVT _switch

Figure 2: LX Series Unit Ventilator Controller Inputs and Outputs

7 x LX-UVL-1 Hardware Output

Object Type #3

Mandatory

Network Variables

Configuration Properties

Maximum Receive Time ( optional)

Override Value (optional)

Manufacturer Configuration Properties

Ob je c t Major Ve rsion Ob je c t Minor Ve rsion

Output Signal Conditioning

PWM Period

Hardware Properties

Default Value

LX Series Unit Ventilator Controller User's Guide 13

The node object displays the nvoUVstate and nvoUValarm variables as manufacturer’s variables. These variables provide information about the alarm conditions in the Unit Ventilator Controller and about the operating state of the device (Figure 3).

LX-UVL - 1 Node

Object Type #0

nviRequest

SNVT _obj_request

Mandatory Network

Variables

Optional Network Variables

Configuration Properties

Location (optional) Device Major Version (optional) Device Minor Version (optional)

Manufacturer

Network

Variables

nvoStatus

SNVT _obj_ status

nvoFileDirectory

SNVT _ address

nvoUVstate SNVT _state_64

nvoUValarm

SNVT _state_64

Manufacturer Configuration Properties

Maximum Send Time

Figure 3: LX Series Unit Ventilator Controller

Node Object Type

Units in LONWORKS Networks

Note: Use this section if you are using the Imperial System of measure. The Imperial System and the International System (SI) are the two main

measurement systems used today. Table 1 compares Imperial units and SI units.

Table 1: Comparing Imperial and SI Units

Imperial Units SI

inch centimeter yard meter mile kilometer degrees Fahrenheit degrees Centigrade

Echelon® SNVTs are based upon SI units. Thus, the most basic structure of the

ONWORKS network is SI based. This basis can lead to some unavoidable

L problems in data conversion if you are using Imperial units.

LX Series Unit Ventilator Controller User's Guide14

The LX-UVL wizard in FX Workbench provides some automatic conversion between SI and Imperial units. However, these are not ideal conversions because a whole number in one system becomes a long decimal fraction in the other. For example, 72°F is approximately equal to 22.22222°C.

Value is written in

Imperial Units.

Data is displayed

for monitoring in

Imperial Units.

Value is translated

to SI units.

Value is rounded.

Value is stored

in SNVT.

Value is read

from SNVT.

Value is rounded.

Value is translated

to SI units.

Units

Figure 4: Writing and Reading Data in Imperial Units in the

ONWORKS Network

The values created by converting Imperial to SI or SI to Imperial are subject to rounding errors. If you enter an Imperial value into a LONWORKS SNVT by using the LX-UVL Controller configuration wizard, the value is converted after it is entered, then rounded and written to the SNVT. When you want to monitor the SNVT, the value must be read from the SNVT, converted, and rounded again before it is displayed. Due to the two conversions and two rounding operations, the value may differ slightly from what you originally entered (Figure 4).

The same process and resulting rounding error applies to Standard Configuration Property Types (SCPTs).

Instructions for changing or modifying the units of measure used on your computer are provided in the Selecting a Measurement System or Selecting a Language section.

Language Selection

The following may require you to change your language settings:

• You changed your regional settings by selecting a different region in the Regional and Language Options dialog box.

• You are working on a site that is in a linguistic region other than your own.

• You are dissatisfied with the language displayed on program menus and dialog boxes.

LX Series Unit Ventilator Controller User's Guide 15

You can change your language settings in the Advanced tab of the Regional and Language Options dialog box. Instructions are provided in the following Selecting a Measurement System or Selecting a Language section.

Selecting a Measurement System or Selecting a Language

To select units of measurement or to select a language:

1. In Microsoft® Windows XP® operating system, click Start > Control Panel. The Control Panel appears.

2. In the Control Panel, open Date, Time, Language, and Regional Options.

3. Under the list titled Pick a Task, select and open the second item titled Change the format of numbers, dates, and times (Figure 5).

Figure 5: Date, Time, Language, and Regional Options Screen

LX Series Unit Ventilator Controller User's Guide16

4. Select your language region from the drop-down list provided. The number,

time, and date formats fill automatically (Figure 6).

Figure 6: Regional and Language Options Dialog Box

5. In the Number box, verify the number format uses a decimal point to indicate

numerals representing values less than 1. For example, use 123,456,789.00, not 123 456 789,00. You must use a decimal point for the correct display of

numerals.

6. In the Regional Options dialog box, click Customize.

LX Series Unit Ventilator Controller User's Guide 17

7. Click on the drop-down arrow next to the box labeled Measurement system and select Metric (Figure 7).

Figure 7: Customize Regional Options

8. Verify the Decimal symbol box contains a decimal symbol. If the Decimal symbol box does not contain a decimal symbol, select the symbol in the box, and click Apply.

9. Click OK.

10. Click the Advanced tab and choose a language region by selecting from the drop-down list. Verify the correct language appears on program menus.

11. Click OK.

You have now set the units to appear in the LX-UVL wizard. If you have chosen to display Imperial units, remember that the SNVTs are still using SI units. If you are viewing the data in Imperial units, you are viewing a converted, rounded value.

LX Series Unit Ventilator Controller User's Guide18

Unit Ventilator Controller Installation Overview

Figure 8 shows one possible installation of the Unit Ventilator Controller. Inputs, outputs, ducts, and heating or cooling units have been marked for your convenience.

Note: Not all possible sensors are shown.

LX-UVL- 1 Installation Overview

Unit Ventilator Enclosure

Damper

Intake A ir

Filter

OAH

Fresh Air

(Economizer)

Damper

Unit Ventilator Enclosure

Mixed

Air

C O

3 Fan

Speeds

Return

MAT DATOAT

Air

RAT

Heating

Coolin g

Unit Ventilator Enclosure

Humidifier

Discharge

Air

Sensor Symbols

Humidity Temperature Carbon Dioxide

Digital Input

Humidity

Temperature

Setpoint Offsett

MAT Mixed Air Temperature

C O

OAH Outside Air Humidity

OAT Outside Air Temperature

Occupancy

Conditioned Space

RAT Return Air Temperature DAT Discharge Air Temperature

Figure 8: Possible LX-UVL Installation

Inputs

The Unit Ventilator Controller has six universal inputs. You can configure universal inputs by using the Unit Ventilator Controller configuration wizard. Universal inputs are configured as either:

• analog inputs sensing either current or voltage, or

• digital inputs or 10k ohm resistance inputs Note: Because the Unit Ventilator Controller can connect to a maximum of six

sensors, you may want to connect some sensors using the LONWORKS network. All valid network inputs have priority over hardware inputs.

LX Series Unit Ventilator Controller User's Guide 19

10k Ohm or Digital Input

The universal input, when configured as a 10k ohm or digital input, accepts a 10k ohm resistance input or a digital input such as a switch, also known as a cold contact.

The 10k ohm resistance range accommodates 10k ohm thermistors used in space temperature sensors or duct temperature sensors, or a 10k ohm potentiometer used as a setpoint offset.

Use the conversion table for resistance input of more than 10k ohm. The digital range accommodates the occupancy contact, bypass switch, and window switch.

See Figure 9 for wiring information for both 10k ohm resistance and digital inputs.

LX-UVL

Both inputs are configured as 10 k Ohm

or Digital Input Configuration could be done

with either the LX -UVL wizard in or the

Hardware Input Wizard

Figure 9: 10k Ohm or Digital Input

I2I

–

++ + + +

I4 I6I5

––

Thermistor

10kO hm

Contact

NO -NC

LX Series Unit Ventilator Controller User's Guide20

Analog Inputs

Analog inputs include current inputs with a range of 4 – 20 mA, and voltage inputs with a range of 0 – 10 VDC.

4 to 20 mA Analog Input, Externally Supplied

Current inputs require a power supply either on the sensor or wired in series with the sensor. To construct the current input, a 500-ohm 0.25-watt resistor is placed across the Unit Ventilator Controller’s input terminals. See Figure 10 and Figure 11.

LX--UVL

–

++++++

I2I

––

1 8

Resistor:

500

Ω −

Watt

Internal 24

powersupply

VDC

4–20mA

–

Controller source

output 4 – 20 mA

Sensor

Figure 10: Sensor Powered Analog Input

LX-UVL

Resistor:

500

VDC

I ++++++

–

Ω −

– +

I2I

Watt

––

4–20mA

1 8

O=ohm

Senso

–

O=ohm

Figure 11: Externally Powered Analog Input

LX Series Unit Ventilator Controller User's Guide 21

Sensors and Switches

The following sensors and switches can be connected to the Unit Ventilator Controller. See Table 3 for the sensor and switches preferred SNVT types.

Auxiliary Alarm Input

This input is used to relay an alarm from an external device onto the building network.

Bypass Contact Input

If the UVC is in unoccupied or standby mode, you can use switch closure on the bypass contact input to cause the controller to enter occupied mode for the time period time set as the bypass time.

CO2 Level Input

Use this input to monitor the CO2 concentration. The CO2 concentration can be used for Demand Control Ventilation (DCV) and to set the minimum damper

position during heating or cooling operations. If you do not want to use the CO2 concentration input, the minimum damper

position can be set in a fixed position, or as a fixed percentage of fresh air intake. You can find the fresh air intake percentage by a calculation of the return air, outdoor air, and mixed air temperatures.

Discharge Temperature Input

Use the discharge temperature input to maintain the discharge air temperature between the minimum and maximum discharge air temperature.

The discharge temperature setpoint is determined by a linear equation between the minimum and maximum discharge air temperature and the terminal load. When there is a high heating demand, the discharge temperature setpoint moves to its maximum temperature. Conversely, for a high cooling demand, the discharge temperature setpoint moves to its minimum temperature. The discharge temperature setpoint can be viewed in the nvoDischargSetPt.

Economizer Enable Input

Select this input to allow switch closure to enable the economizer . The economizer position can then be controlled in several different ways. See the Ventilation section.

Emergency Contact Input

Use switch closure on this input to cause the UVC to begin emergency operation. See the Emergency Operation

Fan Speed Selector Input

section.

Fan speed selector gives the Unit Ventilator Controller the ability to select up to three different fan speeds.

LX Series Unit Ventilator Controller User's Guide22

Fan State Input

The fan state input detects whether one of the three fan speeds is ON or OFF . If the fan state input does not correspond with one of the fan outputs for a time period known as the alarm delay, then an alarm becomes active. If the fan state input is OFF, while one of the fan outputs is ON, then equipment requiring air circulation remains OFF or does not modulate.

Note: All outputs except for the fan are disabled when the fan state is OFF.

Mixed Air Temperature Input

The mixed air temperature can be monitored by an alarm, thereby provide early warning of any malfunction.

Without mixed air and discharge air temperatures, the outside air damper cannot exceed the minimum position as determined by the Fresh Air Minimum Input Damper Position on the General Settings screen of the LX-UVL configuration wizard.

See the Return Air Temperature Input section for more information.

Mode Selector

Mode Selector enables selection of different modes of operation by means of an analog signal, such as resistance, voltage, or current input.

The modes of operation available for selection from this input are auto, heat, cool, fan only, and OFF. Table 2 describes the modes of operation.

Table 2: Modes of Operation

Mode of Operation

Auto Operates according to its setpoints and scheduled occupancy states; this means

Heat Operates according to the heating setpoints in heating mode only. The heating

Cool Operates accordin g to the cooling setpoints in cooling mode only. The cooling

Fan Only Configures the fan ON during the scheduled occupied state. Heating and cooling is

OFF Disables the control loop to OFF. All outputs are in the OFF state.

Description

that the Unit Ventilator Controller controls heating, cooling, duct pressure, and the fresh air damper, according to the setpoints and the configuration properties you enter. The Unit Ventilator Controller switches between unoccupied, occupied, standby , and bypass modes according to its schedule, and between the occupancy and bypass contacts if these contacts are present.

setpoint may change as the controller switches scheduled states. Cooling mode is unavailable. The fan is ON when heating is ON; the fan is OFF at other times unless configured as ON during occupied periods.

setpoints may change as the controller switches scheduled states. Heating mode is unavailable. The fan is ON when cooling is ON; the fan is OFF at other times unless configured as ON during occupied periods.

not available. Fan configuration is found on the Fan-Valve screen of the Unit Ventilator Controller configuration wizard.

LX Series Unit Ventilator Controller User's Guide 23

Occupancy Input

Use the switch closure on the occupancy input to set the Unit Ventilator Controller to occupied mode. The UVC exits occupied mode when the switch is opened. Unless the controller is in bypass mode, the occupied contact does not function if the network variables nviOccCmd and nviOccManCmd are set to unoccupied.

Outdoor Enthalpy Input

Use outdoor air enthalpy to determine if free cooling is permitted. The Ventilator Unit Controller also accepts input directly from an outdoor enthalpy sensor.

Outdoor Humidity Input

You can use outdoor humidity and temperature to calculate the outdoor enthalpy. Outdoor enthalpy can be used to determine if free cooling is permitted.

Outdoor Temperature Input

If outdoor humidity is available, use outdoor temperature to calculate outdoor enthalpy and Optimum Start times. Outdoor temperature or outdoor enthalpy is used to determine if free cooling is permitted. See the Optimum Start and Ventilation sections for more information.

Return Air Temperature Input

The return air temperature is used to prevent the coils from freezing due to cold bypass air. See the General Settings Configuration section.

Position the return air temperature sensor either before or after the bypass damper. Indicate the position of the return air temperature sensor in the General Settings tab of the Ventilation Controller configuration wizard.

When the return air temperature sensor is positioned before the bypass damper, return air temperature can be used instead of the space temperature. To do this, the fan must be ON and the space temperature must be unavailable.

When the return air temperature sensor is positioned after the bypass damper, use the following temperatures to calculate the required amount of intake air:

• mixed air temperature

• outdoor air temperature

• return air temperature Return air temperature can be monitored by an alarm. See the General Settings

Configuration section for more information.

Setpoint Offset Input

This input provides a means of varying the setpoint during occupied and standby modes. The values from this input are added to the pair of active setpoints. See the Calculating the Space Temperature Setpoint section.

LX Series Unit Ventilator Controller User's Guide24

Space Enthalpy Input

Use the space enthalpy input value and the outdoor space enthalpy to enable or disable free cooling. The Rooftop Unit Controller also accepts input directly from a space enthalpy sensor.

Space Humidity Input

Use the space humidity sensor to provide the UVC with the space relative humidity. Relative humidity can be used as an input to the humidity control PID loop.

The UVC can calculate space enthalpy when provided with relative humidity and temperature. Space enthalpy can be compared to outside enthalpy to enable or disable free cooling.

Space Temperature Input

The UVC uses the space temperature to control heating or cooling operations. One of the following inputs must be present for the controller to work:

• space temperature

• nviSlave The space temperature sensor can be a 10k ohm thermistor or provide a voltage or

current input to the board.

Water Temperature Input

The Unit Ventilator Controller provides heating or cooling through a single two-pipe system with a heating or cooling valve. If this system is used, the device must know the state, either hot or cold, of the available water. When the hardware water temperature input is used, the Unit Ventilator Controller determines if the water is hot or cold enough for heating or cooling.

The network inputs nviHotW ater and nviWaterT emp are available for receiving the water state or temperature. If nviHotWater state and value are zero, then the UVC functions as if the water is cold. If nviHotWater state and value are not zero, then the controller functions as if the water is hot. If the water temperature is colder then the space temperature, the water is considered cold; if water temperature is higher than the space temperature, the water is considered hot. Both inputs have priority over the hardware input; however, if both values are received, nviHotWater has priority over the nviWaterTemp.

LX Series Unit Ventilator Controller User's Guide 25

Window Contact Input

If the Unit Ventilator Controller is in occupied, bypass, or standby mode, and the ventilator is in operation (meaning that one of the fan speeds is ON), then a switch closure on the window contact input causes the UVC to enter unoccupied mode. All outputs are turned OFF until a demand from the unoccupied cooling and heating space temperature setpoints arrives and commands the unit into heating or cooling.

Table 3: Sensor and Switch Preferred SNVT Type

Sensor or Switch Preferred SNVT Type

Auxiliary Alarm Input SNVT_amp

Bypass Contact Input SNVT_lev_disc

Level Input SNVT_ppm

Discharge Temperature Input SNVT_temp

Emergency Contact In put SNVT_lev_disc

Fan Speed Selector Input SNVT_lev_disc

Fan State Input SNVT_amp

Mixed Air Temperature Input SNVT_temp

Mode Selector SNVT_hvac_mode Occupancy Input SNVT_lev_disc

Outdoor Enthalpy Input SNVT_enthalpy Outdoor Humidity Input SNVT_percent Outdoor Temperature Input SNVT_temp

Return Air Temperature Input SNVT_temp

Setpoint Offset Input SNVT_temp

Space Enthalpy Input SNVT_enthalpy Space Humidity Input SNVT_lev_percent Space Temperature Input SNVT_temp

Water Temperature Input SNVT_temp

Window Contact Input SNVT_lev_disc

SNVT_amp_ac SNVT_amp_f SNVT_lev_disc

SNVT_lev_occupancy

SNVT_temp_p

SNVT_lev_occupancy

SNVT_amp_ac SNVT_amp_f

SNVT_temp_f

SNVT_lev_occupancy

SNVT_temp_p

SNVT_temp_f

SNVT_temp_diff

SNVT_temp_f

SNVT_switch

SNVT_lev_percent SNVT_switch SNVT_temp_f SNVT_temp_p

SNVT_switch

SNVT_temp_f

SNVT_switch

SNVT_lev_percent SNVT_switch SNVT_lev_disc

SNVT_temp_p

SNVT_switch

SNVT_temp_f

SNVT_temp_p

SNVT_temp_f SNVT_temp_p

SNVT_temp_p

SNVT_occupancy

LX Series Unit Ventilator Controller User's Guide26

Outputs

The Unit Ventilator Controller has five digital outputs (DO1, DO2, DO3, DO4, and DO5), and two analog outputs (AO1 and AO2). Descriptions of these outputs follow.

Analog Output

The Unit Ventilator Controller analog outputs are versatile and can be configured as analog, digital, or PWM outputs. When the analog output is configured with the wizard as a digital output, it supplies 60 mA at 12 VDC. This ability is useful when driving relays external to the board. See Figure 12.

The characteristics of the analog outputs are described in Table 4.

Analog Output Protection

Analog Outputs are protected by an auto-reset fuse with a maximum current capacity defined by the following two points:

• 100 mA at 68°F (20°C)

• 0 mA at 140°F (60°C)

Connect a diode to the relay terminal.

(Ir = 1A at Vr=25 V)

12Vdc Relay

Max load 200 Ohm

180

DO1 C DO2 C DO3 C DO4 C DO5 C AO1 AO2–

Figure 12: Analog Output Driving an External Relay

Table 4: Tri-Mode Analog Output Characteristics

Mode Maximum Current and Voltage Voltage Range

Digital 60 mA at 12 VDC (200 ohm load) 0 – 12 VDC Analog 50 mA at 10 VDC 0 – 10 VDC (linear) PWM 50 mA at 10 VDC 0 or 10 VDC

Digital Outputs

The digital outputs of the UVC use triacs to switch the output signal. Each digital output is capable of conducting 1 ampere.

The digital outputs work as a switch to control the current (Figure 13). The current source is separate from the transformers supplying the current for the UVC controller.

LX Series Unit Ventilator Controller User's Guide 27

The UVC uses a half-wave power supply. Any other half-wave power supply that connects with the controller through the outputs or inputs must be in phase with the power supply of the controller. Do not share grounds between a full-wave and a half-wave power supply.

Power Supply

24 VAC

Max. Current 1A at 24 VAC

DO1 C DO2 C DO3 C DO4 C DO5 C AO1 AO2–

Figure 13: Unit Ventilator Controller Digital Outputs

You can reverse each of the digital output’s scales by using the Unit Ventilation configuration wizard. Normally , ON is a 100% output; when the output is reversed, ON is a 0% output.

You can override all digital outputs to a previously set value using the UVC object override command. The override values are set during the configuration process. The configuration wizard provides a menu for issuing object commands, including the override command. See the Object Manage section for more information.

LX Series Unit Ventilator Controller User's Guide28

Staged Outputs

You can organize the outputs into stages when there are multiple heating or cooling outputs. Stages turn on sequentially one after the other. The heating or cooling stages (n) must be open for the period of time specified in the minimum heating period before heating or cooling stage (n+1) can turn on. For example, heating stage 1 must be open for the minimum heating period before duct heating stage 2 turns on. See Figure 14.

Heating commanded to 100% ON at this time.

Stage 1

turns ON.

100%

Stage 1 ON Stage 1 ON

Heating

Effort

Time

Minimum

heating

period

Stage 2

turns ON.

Stage 2 ON

Minimum

heating

period

Stage 3

turns ON.

Stage 3 ON Stage 2 ON Stage 1 ON

Minimum

heating

period

Figure 14: Staged Outputs

Output Selections

There are 31 possible output selections. Several output selections are dependent upon other output selections. For example, cooling 1–4 can be blocked depending on the setting of the reversing valve.

Fan Speed 1–3

This output provides digital fan speed control. See the Fan Operation section for more information on fan speed operation.

Heating Outputs 1–4

Heating outputs one to four are staged outputs that are turned ON after heating valve outputs, if any, are 100% open.

Cooling Outputs 1–4

Cooling outputs 1-4 are staged outputs, which are turned ON after cooling valve outputs, if any, are 100% open.

Reversing Valve

The reversing valve has two states. If the reversing valve is defined and is ON, then cooling outputs 1–3 act as heating outputs.

LX Series Unit Ventilator Controller User's Guide 29

Humidifier and Dehumidifier Outputs

Both digital and analog humidifier and dehumidifier outputs are available. The fan must be ON to enable the humidifier and dehumidifier outputs.

The UVC uses the assigned outputs to maintain the humidity at a level defined by the humidity setpoint on the general settings menu. A delay occurs when switching between humidification and dehumidification. You can enter the time period for the delay on the general settings screen. The Unit Ventilator Controller also offers the ability to dehumidify with the cooling coil. See the Humidity Control section for more information.

Minimum Fresh Air Enable (MIN_FRESH_AIR_ENABLE)

This output enables the fresh air damper to move to the minimum position. Minimum fresh air is enabled when the occupancy state is OC_OCCUPIED, or OC_BYPASS and the fan is ON.

Economizer Enable

When this output is ON, the economizer can be used for free cooling. This output is enabled when the outdoor air temperature is below the economizer maximum outdoor temperature.

Heat Valve ON-OFF

This output operates the digital heating valve.

Cool Valve ON-OFF

This output operates the digital cooling valve.

Heat Cool Valve ON-OFF

This output operates the digital heating-cooling valve according to the water temperature.

Heat Valve Open or Close

These outputs operate heating floating valves.

Cooling Valve Open or Close

These outputs operate cooling floating valves.

Heat Cool Valve Open or Close

These outputs operate heating-cooling floating valves according to the water temperature.

Fan Speed Modulate (FAN_SPEED_MOD)

Provides a variable speed fan control output.

LX Series Unit Ventilator Controller User's Guide30

Heating Modulate (HEATING_MOD)

Provides the modulated heating control output.

Heating or Cooling Valve Modulate (HEATING_VALVE_MOD) (COOLING_VALVE_MOD)

These outputs provide modulated heating or cooling valve outputs.

Fresh Air Damper Modulate (FRESH_AIR_DAMPER_MOD)

This output provides a modulated fresh air damper signal.

Fresh Air Damper Open or Close

These outputs operate the floating fresh air damper.

Mode Selection

The UVC has several different modes of operation. Each mode has a unique set of setpoints. Modes can be initiated as a result of any one item in the following list:

• change of value in nviOccCmd

• change of value in nviOccManCmd

• occupied button press

• bypass button press

• window open/close contact While in any mode, the controller can enter a heating or cooling state as required to

maintain the space within the limits of the setpoints. Setpoints for each mode are shown in Table 5.

Network Variables Used for Mode Selection

Table 5: Values of nviOccCmd or nviOccManCmd and Modes

Identifier Unit Ventilator Controller

Mode

OC_OCCUPIED Occupied mode Occupied heat and cool OC_UNOCCUPIED Unoccupied mode Unoccupied heat and cool OC_BYPASS Bypass mode Occupied heat and cool OC_STANDBY Standby mode Standby heat and cool OC_NUL Invalid data Unoccupied heat and cool

The network variable nviOccCmd commands the UVC to change modes according to the value of the variable. The value of nviOccCmd is changed by a schedule or other supervisory input.

Setpoints

LX Series Unit Ventilator Controller User's Guide 31

You can manually command the UVC to change modes through network variable nviOccManCmd. Because manual commands (commands entered by the operator) have priority over mode commands from a scheduler node, nviOccManCmd has priority over nviOccCmd. Both network variable inputs have priority over the occupancy contact or bypass button press. Table 5 shows possible values of nviOccCmd and nviOccManCmd.

The network variable nviOccManCmd has priority over nviOccCmd. Therefore, mode commands entered manually have priority over mode commands from a scheduler node. Both network variable inputs have priority over the occupancy contact or bypass button press. See Table 6.

Table 6: Priorities of Mode Changing Inputs

Priority Level

1 Window Contact Enter unoccupied mode 2 nviOccManCmd Manual mode change 3 nviOccCmd Scheduled mode change 4 Occupancy contact Enter occupied mode 5 Bypass button press Enter bypass mode and start the

1. Priority 1 is the highest.

Input Function

bypass timer

Certain conditions must exist for the controller to be in either unoccupied or occupied mode. If nviOccCmd and nviOccManCmd are set to OC_NUL, OC_BYPASS, or OC_STANDBY, and the occupancy contact is OFF or unassigned, then the UVC is in unoccupied mode. If nviOccCmd and nviOccManCmd are set to OC_NUL, OC_BYPASS, or OC_STANDBY, and the occupancy contact is ON, then the Unit Ventilator Controller is in occupied mode. However, when you press the bypass button in either unoccupied or standby mode, it causes the Unit Ventilator Controller to enter bypass mode.

When the window contact is ON, the schedule is set to OC_UNOCCUPIED. The effect on the Unit Ventilator Controller is to shut down the fan and all other mechanical equipment. For example, if the window is opened, an unoccupied room remains unheated ensuring that heat and energy is not lost.

Occupied Mode

Occupied mode ensures the building environment is comfortable for building occupants.

LX Series Unit Ventilator Controller User's Guide32

Starting Occupied Mode

Occupied mode uses the occupied setpoints that you set in the configuration wizard. During occupied mode, the UVC uses the damper and outputs to heat or cool as required to maintain the space within the limits set by the occupied setpoints. If configured, the UV also controls fresh air intake to maintain CO2

concentration as configured. Occupied mode begins as result of one of the following events:

• A command is received on nviOccManCmd or nviOccCmd. To modify these network variables, use a computer connected to a network to manually command nviOccManCmd, or use the building schedule to modify nviOccCmd.

• The occupancy switch is closed when both nviOccCmd and nviOccManCmd are set to OC_NUL, OC_BYPASS, or OC_STANDY.

Ending Occupied Mode

The Unit Ventilator Controller exits occupied mode when any one of the following events occurs:

• Another state is commanded through network variable nviOccManCmd. This method could be used for a manual override from a computer.

• Another state is commanded through network variable nviOccCmd. This method could be used with a scheduler node.

• The occupancy contact opens while nviOccCmd and nviOccManCmd are set to OC_NUL, OC_BYPASS, or OC_STANDY.

• The window contact is closed; the occupancy status sets to OC_UNOCCUPIED.

Unoccupied Mode

Unoccupied mode is the mode used by the Unit Ventilator Controller when the building is empty overnight or over a weekend. By allowing the space temperature to vary greater than in occupied mode, unoccupied mode reduces cost. Despite the greater temperature variance, unoccupied mode keeps the building close enough to the occupied range of temperature ensuring it can be made ready quickly for occupancy on a regular schedule.

Starting Unoccupied Mode

Unoccupied mode uses the unoccupied setpoints that you set in the configuration wizard. It cannot begin if the Unit Ventilator Controller is currently in bypass mode. Unoccupied mode begins as result of one of the following events:

• The unoccupied state is commanded by nviOccManCmd. This method could be used for a manual override.

LX Series Unit Ventilator Controller User's Guide 33

• A schedule change by a supervisory node sets the network variable nviOccCmd to OC_UNOCCUPIED. Because nviOccManCmd has priority over nviOccCmd, nviOccManCmd must be set to OC_NUL for the schedule change to occur.

• The occupancy contact is open or not assigned and both nviOccManCmd and nviOccCmd are set to OC_NUL. This method can be used to manually switch between occupied and unoccupied modes.

• The window contact is opened.

During the unoccupied state, the controller heats or cools the space as required to maintain the temperature within the limits described by the unoccupied setpoints. The fresh air damper is closed unless a cooling demand exists and the damper is enabled.

Note: In unoccupied mode, the setpoint offset from input or network variable has

no effect on the effective setpoint.

Ending Unoccupied Mode

Unoccupied mode ends when any one of the following occurs:

• Another mode is commanded by nviOccCmd while nviOccManCmd is set to OC_NUL. This method can be used to implement a schedule.

• Another mode is commanded by nviOccManCmd. This method can be used as a manual override.

• The bypass button on the space temperature sensor is pressed. This button short-circuits the sensor.

• The occupied contact is closed and both nviOccCmd and nviOccManCmd are invalid.

• The bypass contact input is pressed.

• The window contact is closed. The Unit Ventilator Controller enters the currently scheduled mode or the mode currently commanded by the occupancy contact.

Bypass Mode

Bypass mode uses the occupied setpoints to provide a comfortable environment when individuals are using a space outside of the normal scheduled time.

Bypass mode is temporary. The duration of bypass mode is a time period called bypass time. Bypass time is set on the General Settings configuration screen.

When the Unit Ventilator Controller enters bypass mode, the bypass time period begins; when the bypass time period ends, the Unit Ventilator Controller exits bypass mode.

LX Series Unit Ventilator Controller User's Guide34

Starting Bypass Mode

The Unit Ventilator Controller can be commanded to enter bypass mode by either nviOccManCmd or by nviOccCmd. See the Network Variables Used for Mode Selection section for more information.

The Unit Ventilator Controller enters bypass mode when any of the following occurs during unoccupied or standby mode:

• The bypass button on the space temperature sensor is pressed.

• The bypass contact is closed. Note: The Unit Ventilator Controller does not enter bypass mode if the bypass

time is set to zero.

Ending Bypass Mode

Bypass mode ends as a result of one of the following events:

• Occupancy contact is closed–the Unit Ventilator Controller exits bypass mode

and enters occupied mode.

• The window contact is closed

• The bypass timer expires–the Unit Ventilator Controller enters the currently

scheduled mode, or the mode currently commanded by the occupancy contact.

If bypass mode ends due to the expiration of bypass time and nviOccManCmd is set to OC_BYPASS, the controller sets nviOccManCmd to OC_NUL. This scenario returns occupancy control to a scheduler using network input nviOccCmd or to an occupancy contact.

If nviOccManCmd is not set to OC_NUL, it has priority over nviOccCmd and the occupancy contact.

Standby Mode

In standby mode, the space temperature is allowed a greater amount of variance than in occupied mode. Like unoccupied mode, the space is maintained at a temperature close enough to the occupied setpoints ensuring it can be made ready for occupancy quickly. Standby is intended for areas such as meeting rooms that are intermittently occupied during the normal working day.

Starting Standby Mode

Standby mode setpoints are entered during the Unit Ventilator Controller configuration.

The Unit Ventilator Controller enters standby mode as a result of:

• a scheduler node writing to nviOccCmd, or

• an operator writing a command to nviOccCmd and/or nviOccManCmd

LX Series Unit Ventilator Controller User's Guide 35

Note: Any commands by nviOccCmd can be overridden by nviOccManCmd as

shown in Table 5. For nviOccCmd to be effective, nviOccManCmd must be set to OC_NUL.

Ending Standby Mode

The Unit Ventilator Controller exits from standby mode when any of the following occurs:

• The bypass button on the temperature sensor is pressed or the bypass contact input is ON. These events initiate bypass mode.

• The occupancy contact is closed. This initiates occupied mode.

• The network variable nviOccManCmd is set to another value by an operator or program.

• The network variable nviOccManCmd is set to another value while nviOccManCmd is set to OC_NUL. This method can be used to follow a schedule.

• The window contact is closed; the occupancy status sets to OC_UNOCCUPIED.

Slave Mode

The Unit Ventilator Controller enters slave mode when nviSlave (SNVT_hvac_status) is bound to the nvoUnitStatus of another ventilator. The UVC attempts to follow the heating or cooling demand of the other unit.

St ate Selection and Description

The Unit Ventilator Controller enters occupied, unoccupied, standby, and bypass modes depending on the schedule, and other inputs such as the bypass contact switch. Within each mode, the UVC can enter various states such as heating, cooling, night purge, and morning warm-up.

Supervisory Control and Scheduling

The network variable nviApplicMode coordinates the Unit Ventilator Controller with a supervisory control such as a schedule or a Human-Machine Interface (HMI). The variable nviApplicMode is a SNVT_hvac_mode and must be bound to a network variable output that is also a SNVT_hvac_mode from the HMI, supervisory control, or air handler.

When this connection is complete, the HMI or supervisory control sets the Unit Ventilator Controller to different states through nviApplicMode.

For more information about nviApplicMode, see Table 28.

LX Series Unit Ventilator Controller User's Guide36

Calculating the Space Temperature Setpoint

(

When nviApplicMode is set to HVAC Auto, the space temperature setpoint determines whether the unit enters a cooling or heating state. Space temperature setpoint calculations are addressed before state descriptions to ensure your understanding of how the state is selected.

When you configure the Unit Ventilator Controller, you enter three pairs of setpoints for the four operating states. Because bypass mode uses the same setpoints as occupied mode, there are only three pairs. These setpoint pairs are occupied, unoccupied, and standby. They are stored in SCPTSetPnts. SCPT is an acronym for Standard Configuration-Property Types.

The UVC selects a pair of setpoints as the active setpoints depending on the current mode. Then, the active setpoints are modified using the following variables:

• nviSetPoint

• nviSetpointOffset

• Setpoint Input

The Effect of nviSetPoint on the Active Setpoints

The variable nviSetPoint allows you to change the setpoint using FX Workbench. If nviSetPoint has a valid value and if the mode is standby or occupied, then the two active setpoints are calculated as follows:

Setpoint_ move =−

nviSetPo

occupied cool occupied heat

int

)

OffsetSetpoint oveSetpoint_mointsActiveSetppointsActive_Set

The value of Setpoint_move and Setpoint Offset is added to each member of the active setpoint pair. For the following example, the Setpoint Offset value is considered to be zero.

Example: If nviSetPoint is equal to 75°F (23.9°C) and the two setpoints are 72°F (22.2°C) and 68°F (20°C), then:

6872

75oveSetpoint_m

−°=

)

F°=5oveSetpoint_m

The two setpoints become 77ºF (25ºC) and 73ºF (22.8°C). Note: The network variable nviSetPoint is inactive in unoccupied mode.

LX Series Unit Ventilator Controller User's Guide 37

The Effect of a Setpoint Offset on the Active Setpoints

Setpoint offset is added to the pair of currently active se tpoints. For example, if the setpoints are 72°F (22.2°C) and 68°F (20°C) and the setpoint offset is 2F° (1.1C°), then the value of the setpoints with the offset are (72+2)°F (22.2°C+1.1°C) and (68+2)°F (20°C+1.1°C).

The two possible sources of a setpoint offset are the network variable nviSetpointOffset or a hardware input. nviSetpointOffset allows you to change the value of the setpoint offset.

Hardware inputs are secondary to network variable nviSetpointOffset. For the hardware input to be active, the value of nviSetpointOffset must be invalid and occupancy mode cannot be unoccupied. The invalid value for nviSetPointOffset is

621.806°F (327.670°C). The input can be connected to a 10k ohm potentiometer in

the conditioned space.

Ventilation

This section discusses the processes that control ventilation only. Included is a description of the processes that control fresh air intake and that may be active when cooling processes, such as free cooling, are inactive. For an overview of these ventilation processes, see Figure 15.

Ventilation Separate from Free Cooling

Free cooling uses cool outside air to remove heat from the building. Free cooling is only an option and may be disabled in the configuration wizard. Even if enabled, free cooling is always inactive when there is no cooling demand.

In contrast, there is a continuous demand for ventilation during occupied periods and, depending upon your configuration of the system, there may be minimum ventilation during unoccupied periods.

For example, during a heating state, ventilation occurs but free cooling does not. This means that the damper is moved to a position that meets the demands for fresh air without allowing more air to enter than is necessary.

Free cooling is part of the cooling state and is described further in the Free Cooling section.

LX Series Unit Ventilator Controller User's Guide38

Selecting Fresh Air Damper Control for Ventilation Only

(without Free Cooling)

The Fresh Air Damper is closed during unoccupied periods. This diagram shows

damper control during:

 Standby, Occupied and Bypass Mode s; or,  Occupied Mode when free cooling is not in use or is disabled. Free cooling is not

in use whenever the free cooling output is less than minimum fresh air output.

Fresh Air Damper

Select how the

Damper is controlled.

Can use either

of these two

outputs.

UCPTminOutdoorAir

Is no limitation on

fresh air intake is

checked?

SAT Min Supply Temp.

MAT Mixed Air Temperature

SAT Supply Air Temperature

OAT Outside Air Temperature

RAT Return Air Temperature

MAT Low Limit or SAT

Min_Fresh_Air_Enable

Select the

Greatest

Min Supply Temp.

Is CO2 sensor

Inputs to PID Control

SCPTlimitCO2

present?

CO2 PID

Control

CO2 Sensor Value

Fresh_Air_Damper_Mod

Fresh air minimum

input

nviCO2

Is damper position set

as the Fresh Air

Minimum Input?

Proportional Control

Inputs to Proportional Control

Percentage of

fresh air intake

OAT RAT

Fresh air minimum

input

vent

Figure 15: Ventilation Process

LX Series Unit Ventilator Controller User's Guide 39

Control of the Fresh Air Intake

The fresh airflow is configured in the Unit Ventilator Controller configuration wizard. You can control fresh airflow by one of the following options:

• Entering a minimum damper position on the general settings screen of the UVC configuration wizard.

• Comparing mixed air temperature with return and outdoor air temperature. Using this method, the amount of fresh air entering the system can be calculated as a percentage of total air volume. This percentage is compared to the minimum intake specified in the wizard. The result of this comparison is used to move the damper.

Sensing the CO2 concentration within the space and using the output of the CO2 PID Loop to drive the damper (Figure 16).

Figure 16: Damper Control Settings on General Settings Screen

Outputs That Control the Fresh Air Damper

The fresh air damper is controlled by outputs Min_Fresh_Air_Enable, a digital output, or Fresh_Air_Damper_Mod, a modulated output.

Min_Fresh_Air_Enable

This digital output is not for direct use with modulating dampers. It is intended for use with an ON/OFF fresh air damper or automatic economizer control.

LX Series Unit Ventilator Controller User's Guide40

Fresh_Air_Damper_Mod

If the damper is controlled with the Fresh_Air_Damper_Mod output, then the damper is controlled in one of three ways:

• Demand Control Ventilation (DCV): If DCV is used, the damper is closed

when the CO2 level is lower than the CO2 concentration level set on the General Settings menu of the UVC configuration wizard. As the CO rises above this point, the damper modulates to reduce the CO

level while

level

maintaining the mixed air temperature or supply air temperature above the low limits setpoint. The controller uses DCV whenever an input is configured as a CO2 sensor.

• Return, Outdoor, and Mixed Air Temperatures: If the damper is controlled

by comparing return, outdoor, and mixed air temperatures, the fresh air damper is set so that the amount of fresh air is slightly greater than or equal to the minimum amount of fresh air expressed as a percentage of the total air volume. To use return and mixed air temperatures, select Air Volume in the Fresh Air Minimum input.

• Minimum Fresh Air Position: If there is no CO2 sensor and damper position

chosen on the General Settings menu, then the Fresh_Air_Damper_Mod output uses the minimum fresh air position set on the General settings tab of the Unit Ventilation Controller configuration wizard. If the discharge and mixed air temperatures are not available, the damper is always fully closed or in the minimum position set by Fresh Air Minimum Input.

Humidity Control

The UVC maintains the humidity level at the humidity setpoint that you enter on the General Settings menu. The humidity setpoint is stored in UCPThumidityLevelSetpoint. The fan speeds one, two, or three must be ON for humidity control to function.

Humidification and dehumidification outputs have a minimum ON/OFF time. This value is also entered on the General Settings menu.

You can perform humidity control using a PID loop. Enter the PID loop parameters on the PID screen of the Rooftop Unit Controller configuration wizard. For a description of PID loop control, see The PID Loop section.

The UV Controller maintains the humidity level at the humidity setpoint by the following methods:

• switching ON or OFF the HUMIDIFIER_ON_OFF or

DEHUMIDIFIER_ON_OFF

• modulating the HUMIDIFER_MOD or DEHUMIDIFIER_MOD outputs When you select any cooling output, it unlocks the Dehumidifying Settings. To

dehumidify with a cooling coil, you must enter a minimum cooling override value and the fan speed override value. Dehumidification is more efficien t if the air goes through the cooling coil slowly.

LX Series Unit Ventilator Controller User's Guide 41

When you switch between humidification and dehumidification, the Rooftop Unit Controller delays for a fixed time period of 45 minutes.

Cooling State

The Unit Ventilator Controller can control the following cooling types:

• free cooling

• digital cooling

• staged digital cooling

• cooling using heat pump

• floating valve cooling

• modulated valve cooling

The UVC uses free cooling or mechanical cooling. Free cooling uses the cooler outside air to remove heat from the building. Mechanical cooling uses chiller units and cooling coils to remove heat and humidity from the building.

Free Cooling

You can implement several strategies when using free cooling. The strategies can be described by their following input requirements:

• economizer enable input

• outdoor enthalpy

• indoor and outdoor enthalpies

• outdoor air temperature

Economizer Enable Input: The economizer enable output follows the economizer enable input if the input is available by network or by the hardware input. If the economizer enable output is ON, then the fresh air damper can be used for cooling when the mixed air temperature or the discharge air temperature is known.

Outdoor Enthalpy: When outdoor enthalpy is available but not indoor enthalpy, free cooling occurs if the outdoor enthalpy is below the maximum outdoor enthalpy. A deadband of 0.43 Btu (1 kj/kg) is used in this process.

Maximum outdoor enthalpy is set on the Heating-Cooling configuration screen of the Unit Ventilator Controller configuration wizard or by modifying SCPToutdoorAirEnthalpySetpoint.

Outdoor and Space Enthalpies: If the outdoor and space enthalpies are available, free cooling occurs if the outdoor enthalpy is 0.43 Btu (1 kj/kg) below the space enthalpy. Free cooling is not available if the outdoor enthalpy exceeds the space enthalpy.

Outdoor and space enthalpies are made available by the following methods:

• using a network input

LX Series Unit Ventilator Controller User's Guide42

• using data from an enthalpy-calculating sensor

• using humidity and temperature from sensor or network inputs to calculate

enthalpies

Outdoor Temperature: If outdoor temperature is available, but not the enthalpy and the economizer enable input, then free cooling occurs if the outdoor temperature is below the maximum outdoor temperature. A deadband of 1.8 Fº (1C°) space is used in this process.

Maximum outdoor temperature is set on the Heating-Cooling Configuration screen or by modifying UCPTfreeCoolSetpoint.

Note: If discharge air temperature or mixed air temperature is not available, the

Fresh_Air_Damper_Mod output commands the fresh air damper closed or to the fixed minimum position, depending on the fan state input value and occupancy mode. The damper opens fully only during an emergency purge.

When Free Cooling is Used

The Rooftop Unit Controller uses free cooling when the following conditions occur:

• The fan speeds 1, 2, or 3 are ON, or fan speed modulation is at the minimum

speed.

• All heating outputs have been OFF for the minimum amount of time defined

by the Change Over Delay option on the Heating-Cooling Configuration screen UCPTchngeOverDelay.

• nviApplicMode must be set to HVAC_AUTO or HVAC_COOL.

• The space temperature input data must be valid, or the UVC must be slaved to

another unit.

• There must be a cooling demand. A cooling demand results from a comparison

between the space temperature and the active cooling setpoint.

Mechanical Cooling

The UVC turns the mechanical cooling outputs ON when all of the following conditions occur:

• The fan speeds 1, 2, or 3 are ON, or fan speed modulation is at the minimum

speed.

• All heating outputs have been OFF for the minimum amount of time defined

by the Change Over Delay option on the Heating-Cooling Configuration screen UCPTchngeOverDelay.

• nviApplicMode must be set to HVAC_AUTO or HVAC_COOL.

• The space temperature input data must be valid, or the Unit Ventilator

Controller must be slaved to another unit.

• The outdoor temperature must be greater than the Minimum Outdoor

Temperature entered on the Heating-Cooling Configuration screen.

LX Series Unit Ventilator Controller User's Guide 43

• There must be a cooling demand. A cooling demand results from a comparison between the space temperature and the active cooling setpoint.

• The fresh air damper, or economizer, must be at the minimum position.

• If a floating cooling valve is used, then one output must be COOL_VALVE_OPEN and another output must be COOL_VALVE_CLOSE.

The water used for cooling and heating operations must be cold for any outputs, configured as such, to work:

• heat_cool_valve_on_off

• heat_cool_valve_close

• heat_cool_valve_open

• heat_cool_valve_mod

The water is considered cold when the water temperature is colder than the room temperature, or the nviHotWater received value or state is zero.

Note: nviHotWater has priority over the water temperature read from either the

input sensor or nviWaterTemp.

Cooling Demand

Cooling demand results from any one of the following:

• the error between the active cooling setpoint and the space temperature

• nviSlave

Cooling Output Sequence

If the Economizer Enable or Fresh_Air_Damper_Mod outputs are connected, and the outside air temperature or outside air enthalpy has reached minimum low, then free cooling is used before mechanical cooling; however, if free cooling cannot satisfy the cooling demand, then the outside air damper is moved to the closed or minimum position and mechanical cooling turns on.

If a cooling valve output is configured, then cooling outputs 1–4 turn ON only after valve outputs are 100% open. Cooling outputs 1–4 are staged outputs–see the

Staged Outputs

section.

A delay occurs between the end of free cooling and the beginning of mechanical cooling. This delay is defined by UCPTfree2MecDelay. You can set the delay on the Heating Cooling screen by typing a value into the Switch Over Delay field.

Ending the Cooling State

Cooling outputs shut off when the bias reaches a negligible amount. However, if the PID loop control has accumulated bias during the cooling stage, cooling outputs may not shut off when the space temperature reaches the setpoint.

LX Series Unit Ventilator Controller User's Guide44

Heating States

The Unit Ventilator Controller controls the following heating types:

• digital heating

• staged digital heating

• heat pump heating

• floating valve heating

• modulated valve heating The Unit Ventilator Controller turns the heating outputs ON when the following

conditions are present:

• Fan speeds 1, 2, or 3 are ON, or fan speed modulation is at the minimum speed.

• Permit valve radiation heating and/or Permit local radiation heating options

are selected.

• All cooling outputs must be OFF for the period of time defined as a Change

Over Delay on the Heating Cooling Configuration screen, unless another input is configured as a reversing valve. If another input is configured as a reversing valve, the first stage of cooling turns ON at the same time as the reversing valve. See the Cooling Outputs Used to Heat section.

Note: You can also use cooling outputs to dehumidify. In this situation, you can

enable both cooling and heating outputs at the same time. The option to disable dehumidification in heating mode was designed to avoid this situation by keeping the cooling outputs OFF for dehumidifying in heating mode.

• The network variable nviApplicMode must be set to HVAC_AUTO or

HVAC_HEAT.

• The UVC must receive the space temperature or it must be slaved to another

unit through nviSlave. Space temperature can be received through a hardware input or through nviSpaceTemp.

• There must be heating demand. See the following Heating Demand

section.

• If a floating heating valve is used, one output must open the heating valve and

another output must close the valve.

The water source used for the heating coils must be hot for the following control outputs to work:

• HEAT_COOL_VALVE_ON_OFF

• HEAT_COOL_VALVE_OPEN

• HEAT_COOL_VALVE_CLOSE

• HEAT_COOL_VALVE_MOD The water is considered hot when the water temperature is warmer than the room

temperature, or when nviHotWater receives a value and states different from zero.

LX Series Unit Ventilator Controller User's Guide 45

Note: The nviHotWater variable has priority for the water temperature either

from the input sensor or nviWaterTemp.

Heating Demand

Heating demand results from any one of the following:

• an error between the active heating setpoint and space temperature

• nviSlave

If heating demand is taken from nviSlave, then the Unit Ventilator Controller is operating in slave mode and is receiving the heating demand from another unit.

Heating Output Sequence

Heating outputs 1–4 are staged outputs. Heating output 1 is the first heating stage in the stage sequence. See the Staged Outputs section for more information.

Heating outputs 1–4 and Heating_Mod do not turn ON until all heating valve outputs are at 100%.

Cooling Outputs Used to Heat

You can use cooling outputs 1–4 to heat if another output is configured as a reversing valve. The reversing valve turns ON at the same moment as the first stage of cooling.

If the cooling outputs are used to heat, then heating outputs 1–4 and Heating_Mod do not turn on until the cooling outputs are at 100%.

Ending the Heating State

The heating state ends when there is no demand for heating, and the first heating stage (if any) has operated for more than the minimum heating period.

If the PID loop control has accumulated bias during the heating stage, heating outputs may not shut off when the space temperature reaches the setpoint. The output shuts off when the bias reaches zero.

Night Purge

Night purge is used to freshen the building air before occupation or to cool down a building before morning occupation. Night purge is a scheduled operation that does not use any setpoints. During night purge, only free cooling is enabled. The damper and fan respond to the cooling demand; heating and cooling outputs are OFF.

The Unit Ventilator Controller enters night purge if nviApplicMode is set to HVAC_NIGHT_PURGE. This can be the result of binding with a supervisory Heating, Ventilating, and Air Conditioning (HVAC) device, an HMI, or a scheduling system.

If frost protection is enabled, the heat turns ON if the temperature in the conditioned space reaches 42.8°F (6°C) and turns OFF at 46.4°F (8°C).

LX Series Unit Ventilator Controller User's Guide46

Morning Warm-up State

The Unit Ventilator Controller enters the morning warm-up state when nviApplicMode has the value of HVAC_MRNG_WRMUP. This value of HVAC_MRNG_WRMUP may be the result of binding nviApplicMode with a network variable from a supervisory network system such as nvoTerminalLoad.

The morning warm up period uses occupied setpoints. The fresh air damper is closed if there is no cooling demand. Morning warm up ends when nviApplicMode commands another state.

Using Night Purge and Morning Warm-up with DCV

The UV provides DCV by using the CO2 sensor to measure air quality . While CO2 is a reliable gauge of the effect of human metabolism upon air quality, it does not

provide any measure of other effects upon air quality. For example, various glues and plastics release gases for an extended period of time after installation in a new building. These gases can produce unpleasant odors and cause eye, nasal, as well as bronchial irritation. The accumulation of these gases does not affect the CO2

level. If CO2 alone is considered, the concentration of these gases may not be sufficiently reduced during occupied periods to ensure the comfort and health of

the building occupants. Similarly, an unoccupied building can accumulate gases and odors caused by

clothing left in lockers, damp drains, and photocopiers programmed to produce manuals during the night. None of these detriments to air quality is detected by a CO2 sensor.

Such problems can be solved by over-ventilating, which is expensive, or by providing a minimum airflow during unoccupied periods. Another solution is to use the night purge or morning warm-up to exhaust the accumulated gases before the start of normal occupation.

While the building is unoccupied, CO2 levels do not increase. Yet the levels of other contaminants increase. During occupied periods, these contaminants may not

be removed by a DCV system that responds only to CO morning warm-up remove all contaminants by flushing the building with fresh air

before the occupied period.

levels. Night purge and

Fan Operation

Three fan speeds are available in the UVC. Fan speeds are started according to the heating or cooling demand and according to the outputs configured in the Unit Ventilator Controller configuration wizard. Normal operation sequence begins with the UVC commanding the first fan speed to turn ON. After this, the UVC starts or modulates all cooling and heating outputs to their maximum capacity according to their respective demands. Finally, all other fan speeds are started according to their respective demands.

LX Series Unit Ventilator Controller User's Guide 47

If the fan option Always On in occupied mode is selected and the occupancy status is OC_OCCUPIED or OC_BYPASS, the first fan speed is ON. Otherwise, the first fan speed starts according to a cooling or heating demand.

Fan speeds two and three are controlled by a cooling and heating demand. However, heating outputs and cooling outputs must be configured so these fan speeds can start.

Fan speeds two and three are used to increase cool or hot air volume in the room. For example, during a heating demand, it would not be appropriate to increase the air volume if the discharge air is not reheated. This situation creates discomfort for room occupants as they receive colder air.

The minimum time that any fan speed must be ON before it turns OFF, and the minimum time that any fan speed must be OFF before it turns ON, are both set in the Fan-Valve screen of the UVC configuration wizard. Enter a value in the ON/ OFF period box on that screen. See Figure 17.

Figure 17: Fan-Valve Screen of the Unit Ventilator Controller

Configuration Wizard

Terminal Load

T erminal load describes the ener gy consumption of a Unit Ventilator Controller for both heating and cooling operations. The effect of the economizer damper may be included or excluded from the terminal load on the General Settings screen. The network variable nvoTerminalLoad transmits the terminal load of the controller over the network.

LX Series Unit Ventilator Controller User's Guide48

Heating Terminal Load

Negative terminal load numbers represent the heating terminal load. Heating effort increases as the terminal load decreases. At 100% heating effort, the terminal load is -100% (Figure 18).

Heating Terminal Load

Terminal Load

0%-50%-100%

Time

50%

100%

Heating Effort

Figure 18: Heating Terminal Load

LX Series Unit Ventilator Controller User's Guide 49

Cooling Terminal Load

Positive numbers represent the cooling part of terminal load. The terminal load increases as cooling effort increases. At 100% cooling effort, the terminal load is 100% (Figure 19).

Cooling efforts often have two components: a fresh air damper that can be used to cool the building if outside air is cool enough, and a mechanical cooling system composed of cooling coils that carry heat away from the circulating air.

Cooling Terminal Load

Terminal Load

100%

50%0%

100%

50%

Time

Figure 19: Cooling Terminal Load

Cooling Effort

LX Series Unit Ventilator Controller User's Guide50

Networking Operations

This section describes the operations that occur only as a result of network connections, and provides a description of network variable properties.

Slave Operation

The UVC follows the demands of another unit ventilation controller if nviSlave is bound to the nvoUnitStatus of another unit ventilation controller. The network variable nviSlave is type SNVT_hvac_status.

Load Shedding

If the Unit Ventilator Controller receives an input on nviShedding, it reduces its output. As the value of nviShedding increases, the UVC further reduces its output. For example, if nviShedding is at 25%, heating and cooling outputs do not exceed 75%.

Shedding is stopped if frost protection is enabled, and space temperature falls under 46°F (8°C). The network variable nviShedding is type SNVT_switch.

Setting up Network Connections

The Unit Ventilator Controller interfaces through the Local Operating Network (LON) to other unit ventilators, HMI, and other LONWORKS Network Services (LNS®) based software using the LonTalk® protocol and LNS services.

Whereas the UVC can function without a network connection, the network variables sent and received over the LON by the controller can affect all of its operations.

LX Series Unit Ventilator Controller User's Guide 51

Network Outputs

The network variables have several important attributes in common. These attributes include Heartbeat, Send on Delta, and Throttle.

Table 7 defines the network variable attributes. Table 8 describes the network inputs.

Table 7: Network Outputs

Attribute Description

Heartbeat Heartbeat is the maximum amount of time that must pass before the network

variable automatically transmits. The presence of the heartbeat attribute indicates that functions are proceeding normally. Failure to receive a signal at the other node within a heartbeat interval causes an alarm message to be sent over the network.

Heartbeat is like a countdown timer. Only when the heartbeat timer reaches zero is the heartbeat message sent. Every time that a message is sent, the Heartbeat timer resets to the full heartbeat value.

Heartbeat signals are not always sent. If the monitored data changes more than is required by the Send on Delta setting within a shorter period of time than the heartbeat, the data is sent on the network and the heartbeat message is not sent. Instead, the heartbeat timer is reset and begins to count down again.

Heartbeat provides a method of ensuring that points have not lost connection and that the network is functioning. Whereas throttle restricts how often messages are sent, heartbeat ensures that messages are sent regularly. Heartbeat is disabled by settin g it to zero .

Send on Delta Send on Delta causes a message to be sent when the monitored data

Throttle Throttle sets the minimum update period. Throttle acts as a limit on excessive

changes by a previously set proportion. Send on Delta restricts extraneous network noise by allowing only signals that indicate a meaningful amount of change. If the monitored data does not change for a period of time equal to the heartbeat interval, the data is sent as a heartbeat signal.

network traffic. If the value of a point on the network is constantly fluctuating at a rapid rate and is set to Send on Delta, the network can be flooded by data from that point. Throttle prevents the variable from transmitting more than once every minimum update period regardless of how many fluctuations have occurred during that period. For example, rapid motion of the damper could drastically increase network traffic. Damper oscillations could also cause network traffic problems if data were sent on every cycle of oscillation. Throttle can prevent network congestion in either of these cases by limiting the number of sends per time interval to a meaningful number. Throttle units are in seconds. The larger the throttle number, the less frequently the network variable is transmitted. You can disable throttle by setting it to zero.

Table 8: Network Inputs

Attribute Description

Heartbeat The Heartbeat effect on a network input is set to the maximum time period

that the network variable waits for a message before entering the heartbeat failure state. When a heartbeat failure state is entered, the value becomes invalid and an alarm is sent.

Persistent When the network variable is marked as persistent, the value is written to

EEPROM. Once written to EEPROM, the network variable value is preserved through power outs and resets. Every time a new network variable value is received, the new value is written into EEPROM.

Because EEPROM can only accept a limited number of data writes, be careful how you use the persistent attribute. See the Persistent Network Variables section for more information.

LX Series Unit Ventilator Controller User's Guide52

Optimum Start

Optimum Start prepares the space for occupancy in advance of the occupied period. If you start heating or cooling at the optimum time before the occupied period begins, the UVC provides a comfortable space that is ready for occupancy without wasting energy. Enable Optimum Start on the Options screen of the Unit Ventilator Controller configuration wizard. Select the boxes labeled Enable Optimum Start for heating and Enable Optimum Start for cooling.

The UVC maintains statistics that compare the outside temperature to the time required for the space to reach the occupied setpoints. The UVC uses the statistics to calculate the length of time required for Optimum Start.

Because the Optimum Start time is calculated every day for the current outside air temperature, it is much more energy efficient than simply starting the occupancy period before the actual arrival of occupants.

Enter a value in the Maximum start time box to limit the Optimum Start time period. Optimum Start begins no sooner than the Maximum start time before the occupancy change. For example, if the space enters the occupied mode at 8:00 A.M. and the Maximum start time is 30 minutes, then Optimum Start does not begin until 7:30 A.M. at the earliest. Of course, Optimum Start can still begin at any time that is less than 30 minutes before 8:00 A.M.; for example, 7:41 A.M.

When statistics are not available, you can choose from two options. The first option starts heating or cooling when the space occupancy changes. The second option allows Optimum Start to use the Maximum start time. To enable this feature, select the box labeled Use maximum time if no statistics on the Options configuration screen or set bit #58 of the network variable to UCPTobjectoptions.

Regardless of which setting you choose, the first samples are saved when the UVC does not have any statistics; these samples include the outside air temperature and the time required to reach the setpoint. Each day, Optimum Start uses the time recorded from the previous day’s sample. For example, if the Unit Ventilator Controller recorded that the space reached occupied setpoint in 25 minutes the first day, then on the second day the UVC would begin Optimum Start 25 minutes before occupancy. If a maximum start time has been entered, the UVC may use a value derived from the samples that is less than the maximum start time. However, the controller does not use a start time that is greater than the maximum start time value.

On the third day, the UVC has two samples stored and uses the two samples to calculate the Optimum Start time given the current outdoor temperature. From this point on, all Optimum Starts are statistically calculated by the UVC using its saved samples.

Requirements for Optimum Start

The next state and time to the mode must be defined in advance. There must be a scheduler and the schedule must be properly bound to the Unit Ventilator Controller using nviOccCmd.

LX Series Unit Ventilator Controller User's Guide 53

The network variable nviOccCmd must be set to SNVT type SNVT_tod_event. You can do this using the Changeable Nv Manager view of the device.

Because the Optimum Start is based on statistics calculated from the room temperature and the outside air temperature, the outdoor temperature must be configured as an input or be received from the network through nviOutdoorTemp.

Emergency Operation

Emergency modes are primarily for situations where the ventilation system may affect the spread of smoke or other contaminants. There are two possible situations:

• You want to keep fresh air from entering the building, such as to slow the spread of a fire.

• You want to allow fresh air into the building.

As a result, the unit ventilator has two emergency modes:

• Emergency Purge: An emergency purge stops the fan, stops any heating or cooling, and fully opens the fresh air damper.

• Emergency Shutdown: An emergency shutdown stops the fan, stops any heating or cooling action, and closes the fresh air damper.

LX Series Unit Ventilator Controller User's Guide54

Emergency Initiation

Emergency modes are initiated by:

• Setting nviEmergCmd to EMERGE_PURGE or EMERG_SHUTDOWN.

• Closing the emergency contact wired to the emergency input. The network variable nviEmergCmd has priority over the emergency contact. The

network variable nviEmergCmd is a SNVT_hvac_emerg (103) type. Invalid value is EMERG_NUL.

The emergency contact input can be configured as emergency pur ge or emer gency shutdown on the General Settings screen of the UV configuration wizard. Otherwise, you can modify UCPTobjectOptions:

• Setting bit 54 to 0 selects emergency purge.

• Setting bit 54 to 1 selects emergency shutdown.

Normal Operation

When there is no emergency and operations are normal, nviEmergCmd is set to EMERG_NORMAL.

The PID Loop

Proportional plus Integral plus Differential (PID) loops provide precise control over space temperature and ventilation.

The control loop modulates its output to drive its input to a setpoint. The control loop inputs are the sensor readings of the temperature. For example, the outputs can be the fan speeds and the heating or cooling outputs.

The difference between the input and the setpoint is called the error . The controller output is a function of the error.

SpaceSensor Output

Input

Controller

Setpoint

Output

Figure 20: PID Controller with Input, Setpoint, and Output

LX Series Unit Ventilator Controller User's Guide 55

The Unit Ventilator Controller provides PID control settings through its configuration wizard. Figure 21 shows the PID screen.

Figure 21: PID Screen of the Unit Ventilation

Controller Configuration Wizard

For space temperature, discharge temperature, CO2, and humidity levels, there are settings for proportional, integral, and derivative gains. Each of these gains

contributes to the final output as shown in Figure 22. They are discussed separately in the following sections.

Proportional

Figure 22: Total Output Composed of P, I, and D Components

++ =

Integral

Derivative

Tota l O u tp ut

Proportional

Proportional control provides an output that is proportional to the error. The error is multiplied by a number called the gain. The result is used to produce the output.

For example, if the room temperature is 69°F and the setpoint is 72°F, then the error is 3F°. If the gain is equal to 10% per °F, then the output is 30% of the maximum output value.

Integral

The integral component has a gain and time setting. These work together to remove errors that accumulate over time.

LX Series Unit Ventilator Controller User's Guide56

Gain

Gain is a multiplication factor that adds weight to the integral part of the PID loop. The integral gain is similar to the proportional gain. The error is multiplied by the value you entered as integral gain. If the gain is equal to 5% per °F and the error is 2F°, the integral output is 10% of the maximum possible output signal.

The integral gain differs from the proportional gain in that the output is increased the longer that the error persists. This situation occurs because the product of the error multiplied by the integral gain is periodically added to the output. When you enter the time, you are entering the length of the time period over which the error is added.

Time

Time is the cycle period for the integral part of the PID loop. The cycle period is the time necessary for the integral error to attain the same value as the proportional error.

How It Is Used

Imagine a building in a cold climate where the temperature of a certain space is never quite warm enough. A log of the temperature of this space would produce a graph such as Figure 23.

Heat is OFF.

Setpoint

Heat is ON

Temperature

8:00 8:30 9:0010:00

Time

Figure 23: Never Quite Warm Enough:

Using Only a P Controller

Space Temperature

In Figure 23, the temperature never quite falls low enough to turn on the proportional heat.

LX Series Unit Ventilator Controller User's Guide 57

However, with a proportional integral controller, the error would accumulate over time. Periodically, a portion of the error would be added back into the error. Error would accumulate and would finally be large enough to turn on the heat. See Figure 24.

Space

Heat is OFF.

Setpoint

Temperature

Heat is ON

Temperature

8:00 8:30 9:0010:00

Time

Figure 24: Heating Using a PI Controller

Heat is ON.

Error accumulates.

Derivative

Derivative control opposes sudden changes in the input value. Whereas integral control is able to correct errors that persist over time, derivative control can respond to sudden changes quickly.

Consider a graph of temperature over time. Because the derivative of a function is the rate of change of the function, the derivative of temperature over time is the rate of change of the temperature per unit time. For example, rate of change could be degrees per minute.

Derivative control opposes the rate of change. For example, consider a hospital lobby in the arctic. Because the lobby changes temperature often, it has its own local heaters that are controlled by a PID loop. Every time the hospital doors open, the temperature in the lobby quickly decreases. This sudden drop in temperature is a considerable rate of change. This considerable rate of change is opposed by the derivative control. The derivative control increases the output of the PID loop that increases the output of the heaters. As the lobby temperature becomes closer to the setpoint, the derivative control output decreases to zero as the lobby temperature reaches its setpoint.

Gain

The derivative gain is the amplification of the derivative output. The gain is measured as a percentage per unit of change where a unit is a Centigrade or Fahrenheit degree. If 50 is entered into the Gain box, then each unit of error causes a 50% increase in derivative control output.

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Time

Derivative control normally responds to measured values rather than the actual direct input. By doing so, the derivative control is prevented from creating large, short spikes in the controller output. The spikes are the derivative control response to sudden increase or decrease in error due to setpoint changes.

Time refers to the period between measurements of the input. If the time is set to 3 seconds, and the gain is 25%/F°, then the derivative output is 25% of the error for each degree of error and recalculates every 3 seconds.

Deadband

The deadband is a range of input values. The center of the range is the setpoint. While the input lies within the deadband, deviations from the setpoint are not calculated as errors. The deadband is the range of values that are close enough to the setpoint that their effect is unnoticeable.

If the deadband is equal to 1/2 x to the setpoint + 1/2 x, then the deadband extends from the setpoint - 1/2 x to the setpoint + 1/2 x. The maximum amount of deviation allowed is ± 1/2 x. See Figure 25.

Deadband with Value of x

As long as input stays within the deadband, the error will be zero. As long as the error is zero, the PID loop

Deadband Limits

e d u

i n g a

Deadband Limits

0.5x

Setpoint

will not change its output signal.

As soon as the input exceeds the deadband, the PID loop will sense an error at its input. Whatever the PID outputs will do next, depends

Time

on the PID loop settings.

Input

Figure 25: Effect of Deadband upon PID Loop Error

When you use deadbands, it reduces mechanical wear and tear on moving parts because the mechanical parts no longer oscillate to accommodate trivial errors.

LX Series Unit Ventilator Controller User's Guide 59

Alarm Operation

Shown in Figure 26, the Alarm Configuration screen of the Unit Ventilator Controller configuration wizard provides user-set alarms. You can configure and enable these alarms to match the requirements of your current site. User-set alarms are available for the following control points:

• space air temperature

• discharge air temperature

• return air temperature

• mixed air temperature

• space humidity

• auxiliary alarm

• fan alarm

• pump alarm

In addition to the preceding user-set alarms, other alarms are provided. These include:

• heartbeat alarms for network inputs

• disconnect alarms for sensor points

• emergency mode alarm

Figure 26: Alarm Configuration Screen

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Alarm Features

UVC alarms have a number of features that enable you to automatically and carefully monitor critical system information. Many of these features are visible in Figure 27. Table 9 describes alarm features.

Features of a Deviation Alarm

Space Temp C°

Offset = 2C° Alarm Delay = 10 minutes

10.0 min

Monitored Variable

Setpoint

22 20

Time

Monitored variable exceeds value of offset + setpoint at this time.

An alarm message is not sent as the monitored variable is in the alarm state for less time than the value of the alarm delay.

2.0 C°

10.0 min

Monitored variable enters alarm state at this time.

Alarm message is sent here after the expiration of the alarm delay.

Upper limit of Offset

Lower limit of Offset

Figure 27: Space Temperature Alarm

Table 9: Alarm Features (Part 1 of 2)

Feature Description

Monitored Variable Displays the network variable or control point that is monitored by the

Alarm State Enables when a monitored variable has a value that causes an alarm. Alarm Offset Displays the amount that the monitored variable can deviate from the

Alarm Delay Displays the period of time that the monitored variable must be in the

alarm. For example, if you have an alarm that sends a message whenever a space temperature deviates too far from the setpoint, then the monitored variable is the space temperature.

setpoint before entering the alarm state. See Figure 27. An offset causes the alarm to become active when the value of the monitored variable is greater than or less than the range of values equal to the setpoint plus or minus the offset. Alarms that use an alarm offset are often called deviation alarms.

alarm state before an alarm message is generated. See Figure 27 and Figure 28.

LX Series Unit Ventilator Controller User's Guide 61

Table 9: Alarm Features (Part 2 of 2)

Feature Description

Alarm Low Limit Displays a value that is less than the setpoint. When the monitored

Alarm High Limit Displays a value that is greater than the setpoint. When the monitored

variable becomes equal to or less than the alarm low limit, an alarm message is transmitted over the network. Alar ms tha t use a low limit are often called low limit alarms. See Figure 28.

variable becomes equal to or more than the alarm high limit, an alarm message is transmitted over the network. Alarms using high limits are often called high limit alarms. See Figure 28.

Alarms are transmitted using the network variables nvoUValarm and nvoUnitStatus.

A number of alarms respond to the timing of network variables. Some of these are called heartbeat alarms because they respond to the heartbeat value. The heartbeat is the maximum length of time that can occur between transmissions of a variable on the network. If this time is exceeded, an alarm sounds.

Alarm Types

The UVC uses four types of alarms. Table 10 describes these alarm types.

Table 10: Alarm Types

Alarm Type Description

Digital Alarms Monitors the state of digital network variables or hardware inputs. Digital

High Limit Alarms Reports when an analog network variable or hardware input is greater

Low Limit Alarms Reports when an analog netw ork variable or hardware input is less than

Deviation Alarms Reports when a monitored analog value deviates from its setpoint by

alarms can also indicate when digital network variables differ in state. For example, the fan output and the fan state should always be the same. If they differ, a digital alarm transmits a message on the network.

than a user-set value called a high limit.

a user-set value called a low limit.

more than a user-set value known as an alarm offset.

Alarm Procedure

When an alarm condition occurs, the following changes take place:

• The appropriate bits of nvoStatus and nvoUValarm are set.

• The in_alarm field of nvoUnitStatus is set to 1.

• The network variable nvoUnitStatus transmits information about the unit ventilator object.

The following text sorts the alarms by type, describes the conditions that generate an alarm, and organizes the associated bits of the nvoStatus and nvoUValarm into a table.

LX Series Unit Ventilator Controller User's Guide62

The alarm types are:

• heartbeat alarms

• disconnect alarms

• status alarms

• user-set alarms

Features of an Alarm Using High and Low Limits

Lower Alarm Limit = 18°C

Supply Temp C°

Upper Alarm Limit = 24°C Alarm Delay = 10 minutes

10.0 min

Setpoint

Time

Monitored variable falls below lower limit. An alarm message is not sent as the monitored

variable is in the alarm state for less time than the value of the alarm delay.

Heartbeat Alarms

Monitored Variable

10.0 min

Monitored variable enters alarm state at this time.

Alarm message is sent at this time after the expiration of the alarm delay.

Figure 28: Discharge Temperature Alarm

Upper Alarm Limit

Lower Alarm Limit

Heartbeat time values are set on the Network Input screens of the Unit Ventilator Controller configuration wizard or by modifying SCPTmaxRcvTime.

The column heading Bit # refers to the Bit Number of nvoUValarm. The column programmatic name refers to the programmatic name of nvoUValarm with the format type UNVT_uv_alarms that relays the status of the object. If a heartbeat alarm comes ON, a communication failure alarm sounds. The Bit #13 of nvoStatus, programmatic name comm_failure, turns ON. Table 11 describes Heartbeat Alarms.

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Table 11: Heartbeat Alarms

Monitored Point

Application Mode CO2

Concentration Discharge

Temperature Economizer

Enable Fan Speed

Command Fan State Hardware Output

Value

Mixed Air Temperature

Occupancy Command

Outdoor Enthalpy Outdoor Humidity Outdoor

Temperature Return

Temperature Setpoint Offset Shedding

Command Slave Input Space Enthalpy Space Humidity Space

Temperature Water

Temperature St ate (Hot/Cold)

Monitored Variable

nviApplicMode SCPTmaxRcvTime 1 nviApplicModeHeartBeat nviCO2 SCPTmaxRcvTime 14 nviCO2HeartBeat

nviDischargeTemp SCPTmaxRcvTime 6 nviSupplyTempHeartBeat

nviEconEnable SCPTmaxRcvTime 8 nviEconoHeartBeat

nviFanSpeedCmd SCPTmaxRcvTime 19 nviFanSpeedCmdHeartBeat

nviFanState SCPTmaxRcvTime 7 nviFanStateHeartBeat nviExtCmdOutput(x)SCPTmaxRcvTime 20

nviMixAirTemp SCPTmaxRcvTime 16 nviMixedAirTempHeartBeat

nviOccCmd SCPTmaxRcvTime 3 nviOccCmdHeartBeat

nviOutdoorEnth SCPTmaxRcvTime 18 nviOutdoorEnthHeartBeat nviOutdoorRh SCPTmaxRcvTime 13 nviOutddoorRhHeartBeat nviOutdoorT emp SCPTmaxRcvTime 11 nviOutdoorTempHeartBeat

nviReturnTemp SCPTmaxRcvTime 15 nviReturnTempHeartBeat

nviSetptOffset SCPTmaxRcvTime 2 nviSetPtOffsetHeartBeat nviShedding SCPTmaxRcvTime 9 nviSheddingHeartBeat

nviSlave SCPTmaxRcvTime 10 nviSlaveHeartBeat nviSpaceEnth SCPTmaxRcvTime 17 nviSpaceEnthHeartBeat nviSpaceRH SCPTmaxRcvTime 12 nviSpaceRHHeartBeat nviSpaceTemp SCPTmaxRcvTime 0 nviSpaceTempHeartBeat

nviWaterTemp SCPTmaxRcvTime 4 nviWaterTempHeartBeat

nviHotWater SCPTmaxRcvTime 5 nviHotWaterHeartBeat

Delay Time Bit#Programmatic Name

nviExtCmdOutputxHeartBeat

LX Series Unit Ventilator Controller User's Guide64

Disconnect Alarms

The column heading Bit # refers to the Bit Number of nvoUValarm. The column programmatic name refers to the programmatic name of nvoUValarm with the format type UNVT_uv_alarm that relays the status of the object. If a heartbeat alarm comes ON, an electrical fault alarm sounds. The Bit #11 of nvoStatus, programmatic name electrical_fault, turns ON. Table 12 describes disconnect alarms.

Table 12: Disconnect Alarms

Sensor Time

Disconnected

Space Temperature Sensor

Discharge Air Temperature Sensor

Return Air Temperature Sensor

Mixed Air Temperature Sensor

Outdoor Air T emperature Sensor

Water Temperature Sensor 30 seconds 37 WaterTempSensorFault Setpoint Offset 30 seconds 38 SetpointOffs et El ecF a ul t

30 seconds 32 SpaceTempSensorFault

30 seconds 33 DischargeTempSensorFault

30 seconds 34 ReturnTempSensorFault

30 seconds 35 MixedAirTempSensor

30 seconds 36 Out doorTempSensor

Bit # Programmatic Name

Emergency Mode Alarms

Emergency mode is described in the Emergency Operation section. Emergency mode alarm begins when the emergency mode begins. In Table 13, the column programmatic name refers to the programmatic name of nvoUValarm with the format type UNVT_uv_alarm, which relays the status of the object.

Table 13: Emergency Mode Alarm

Monitored State Bit # Programmatic Name

Emergency Mode 48 Emergency

User-Set Alarms

The column heading Bit # refers to the Bit Number of nvoUValarm. The column programmatic name refers to the programmatic name of nvoUValarm with the format type UNVT_rt_alarm that relays the status of the object. If a user-set alarm comes ON, an out of limits alarm sounds. The Bit #4 of nvoStatus, programmatic name out_of_limits, turns ON.

LX Series Unit Ventilator Controller User's Guide 65

These settings can be entered on the Alarm screen of the Unit Ventilator Controller configuration wizard (Figure 26). Table 14 describes the configuration variables for user-set alarms.

Table 14: Configuration Variables for User-Set Alarms

Monitored Point

Space Temperature

Discharge Air Temperature

Return Air Temperature

Mixed Air Temperature

Space Humidity

CO2 Concentration

Fan State

Auxiliary Alarm Input

Alarm Type

Deviation Active heating

Low Low limit setpoint 41 LowDischargeTemp UCPTsupplyTempA

High High Limit

Deviation active heating

Low low limit setpoint 45 LowMixedAirTemp UCPTmixAirTemp

Deviation setpoint - offset 46 LowSpaceRH UCPThumidity

High CO2 Limit +

Digital Fan input differs

Low lower than low

High higher than high

Setpoints Bit#Programmatic

Name

setpoint-offset Active cooling

setpoint+offset

setpoint

setpoint-offset active cooling

setpoint+offset

setpoint + offset 47 HighSpaceRH

offset

from state of fan output

limit setpoint

39 LowSpaceTemp UCPTspaceTemp

40 HighSpaceTemp

42 HighDischargeTemp UCPTsupplyT empA

43 LowReturnT emp UCPTreturnTemp

44 HighReturnT emp

48 HighCO2Level UCPTCO2Alarm

49 FanStateMismatch UCPTFanCurrent

50 AuxiliaryLowAlarm UCPTauxiliary

51 AuxiliaryHighAlarm UCPTauxiliary

Setpoints/Delta Location

AlarmDelta Field

larmLoLimit Field

larmHiLimit Field

AlarmDelta Field

Alarm LoLimit Field

AlarmDelta Field

Delta Field

Threshold

AlarmLoLimit field

AlarmHiLimit field

Time Delay Location

UCPTspaceTemp AlarmTime Field

UCPTsupplyTemp AlarmTime Field

UCPTreturnTemp AlarmTime Field

UCPTmixAirTemp AlarmTime Field

UCPThumidity AlarmTime Field

UCPTfanAlarm Time

UCPTauxiliary Alarmtime field

Setting up the Unit Ventilator Controller

This section provides you with step-by-step instructions for setting up the Unit Ventilator Controller using the configuration wizard. The definition of the terms used in the configuration wizard and a short explanation of how to use each section of the configuration wizard are provided.

Each screen of the configuration wizard is discussed under its own heading (for example, Heating-Cooling Configuration) and introduced by a large graphic of that screen.

The following information is in the same order as it appears in the Unit Ventilator Controller configuration wizard.

Persistent Network Variables

Note: Read this section about how to make network variables persistent. This

information could save you a great deal of time.

LX Series Unit Ventilator Controller User's Guide66

When the network variable is marked as persistent, the network variable value is written to Electronically Erasable Programmable Read-Only Memory (EEPROM). Once written to EEPROM, the network variable value is preserved through power outs and resets. Every time it receives a new network variable value, the new value is written into EEPROM.

However, EEPROM only accepts a limited number of data writes. The number of writes that EEPROM accepts is large, but it is still limited. If the network variable input is constantly changing, the network variable could exhaust the ability of the EEPROM to store it in permanent memory.

If the value of the network variable is constant, and if it is received on the network input at a fixed time interval, this does not cause the EEPROM to write new data. The EEPROM only writes new data when the data value changes.

For these reasons, network variables that change infrequently (for example, nviSetPoint network variables) are better candidates for persistence than others.

Setting Units

Measurement units are shown at the bottom of the Unit Ventilator Controller configuration wizard menu. Select measurement units before you perform any other tasks. When you change the measurement units, all unsaved information you have entered into Unit Ventilator Controller configuration wizard is lost.

If you are using Imperial units of measure (such as degrees Fahrenheit, inches of water, and Btu), see the Units in LONWORKS Networks section.

However, if you change your system measurement unit, all the SNVT format types also change. The measurement unit you select in the wizard, either SI or Imperial, has an effect on the nvoHwInputx SNVT format type. Once you configure an input through the wizard and select a SNVT Type, the format type is written in the database and a change of the system measurement unit no longer has an effect on that network variable.

Note: To prevent accidental loss of information, click Apply frequently as you

move through the setup procedure. Clicking OK saves the information, but closes the wizard window.

Input Configuration

When you configure inputs, you set the signal type, signal interpretation, and the SNVT that transmits the information over the network. You can configure inputs through the sensor configuration wizard. The sensor configuration wizard can be launched from both the Unit Ventilator Controller configuration wizard and the Hardware Input functional block.

LX Series Unit Ventilator Controller User's Guide 67

Output Configuration

When you configure outputs, you define the function, override value, and signal type. You can configure outputs with the Hardware Output wizard and launch them from the Unit Ventilator Controller configuration wizard Object Outputs Configuration screen (Figure 29). Table 15 describes all possible outputs that you can select from the Object Outputs Configuration screen.

Figure 29: Object Outputs Configuration Screen

Table 15: Output Selection and Description (Part 1 of 2)

Selection Output Description

FAN_SPEED_1 Fan control output, speed 1 FAN_SPEED_2 Fan control output, speed 2 FAN_SPEED_3 Fan control output, speed 3 LOCAL_HEATING_1 Heating control output, stage 1 LOCAL_HEATING_2 Heating control output, stage 2 LOCAL_HEATING_3 Heating control output, stage 3 LOCAL_HEATING_4 Heating control output, stage 4 LOCAL_COOLING_1 Cooling control output, stage 1 LOCAL_COOLING_2 Cooling control output, stage 2 LOCAL_COOLING_3 Cooling control output, stage 3 LOCAL_COOLING_4 Cooling control output, stage 4 REVERSING_VALVE Two state (opened or closed) reversing valve output HUMIDIFIER_ON_OFF Humidifier control output DEHUMIDIFIER_ON_OFF Dehumidifier control output

LX Series Unit Ventilator Controller User's Guide68

Table 15: Output Selection and Description (Part 2 of 2)

Selection Output Description

MIN_FRESH_AIR_ENABLE Minimum fresh air intake enable output ECONOMIZER_ENABLE Eco nomizer enable output HEAT_VALVE_OPEN Heating floating valve output, open command HEAT_VALVE_CLOSE Heating floating valve output, close command COOL_VALVE_OPEN Cooling floating valve output, open command COOL_VALVE_CLOSE Cooling floating valve output, close command HEA T_COOL_VALVE_OPEN Heating/cooling floating valve output, open command HEA T_COOL_VALVE_CLOSE Heating/coolin g floating valve output, close command FAN_SPEED_MOD Fan control output, variable speed HEATING_MOD Modulated heating control output HEATING_VALVE_MOD Modulated heating valve output COOLING_VALVE_MOD Modulated cooling valve output HEA T_COOL_VALVE_MOD Modulated heating/cooling valve output HUMIDIFIER_MOD Modulated humidifier control output DEHUMIDIFIER_MOD Modulated dehumidifier control output FRESH_AIR_DAMPER_MOD Modulated fresh air (economizer) damper control output FRESH_AIR_DAMPER_OPEN Fresh air damper output, open command FRESH_AIR_DAMPER_CLOSE Fresh air damper output, close command

The Output wizard can be launched from both the Unit Ventilator Controller configuration wizard and from the Hardware Output Functional Block. Hardware output could be used to control any equipment that is not related to the Unit Ventilator Controller. To do so, configure the output with the actuator wizard launched from the hardware output functional block. In the Unit Ventilator Configuration wizard, leave the corresponding output UNASSIGNED. To control that output, use the nviExtCmdOutputx.

Output Signal Types

Three possible output signals are available; output types are dependent upon which output signals you select. A brief description of each of the types follows:

Digital - A signal that has only two states: ON and OFF. Pulse Width Modulation (PWM) - A pulsed signal where the time duration of the

pulse, called the duty cycle, varies proportionally to the value transmitted. For example, a larger duty cycle is translated as a larger value.

Analog - A signal that is continuous over its entire range of 0 to 10 volts.

Configuring an Output

To select and configure an output:

1. On the Output screen, numbers in the column Control Output correspond to the

output numbers. Click the drop-down arrow next to the control output number that you want to configure.

LX Series Unit Ventilator Controller User's Guide 69

2. Select an output type. See Table 15 for a brief definition of the possible selections.

3. If you want to assign an override value, select the box labeled Permit Override and then enter an override value as a percentage of the total output value. If you have chosen a digital output, such as FAN_SPEED_1, then the override box changes to provide you with the option of ON or OFF for your override.

Note: Outputs are overridden by use of the Unit Ventilator Controller LONMARK

Object command. This command is available from the Object Manage screen of the Unit Ventilator Controller configuration wizard. Click Override ON to enable the override, and Override OFF to disable it.

4. Select the Local Hardware box if the output is connected to a physical actuator such as a motor or valve.

5. Click Configure.

6. In the Output Type box (Figure 30), click the drop-down arrow and select the output signal appropriate for your application. The output signal selection presented to you is dependent upon the choice you made in Step 2. See the Output Signal Types section for more information.



Figure 30: Hardware Output1

Note: Reverse Output - Normally , an output is ON when the output components

are supplying 100% of the rated voltage. If you want the output to supply 0% of the rated voltage when ON, select the Reverse box. For a digital output, the output is normally ON when the contacts are closed. When you reverse a digital output, the output is ON when the contacts are open.

You have now configured an output.

LX Series Unit Ventilator Controller User's Guide70

Configuring an Output Represented as a Functional Block

To configure an output represented as a functional block:

1. Select the Hardware Output in the LX-UVL wizard and click the Launch

button. The Actuator wizard opens (Figure 31).

Figure 31: Hardware Output Configuration

2. In the Output Type box, select the type of output signal. See the Output Signal

Types section for more information.

Note: Reverse Output - Normally , an output is ON when the output components

are supplying 100% of the rated current and voltage. For a digital output, the ON state occurs when the contacts are closed. If you want the output when ON to supply 0% of the rated current and voltage or for the digital contacts to be open, then select the Reverse box.

3. Enter an override value as a percentage of the total output to assign an override

value.

Note: Normally, digital outputs are closed at 100% and open at 0%. See the

preceding Reverse Output note. Outputs are overridden by use of the actuator LONMARK Object command. This command is available from the Object screen of the actuator wizard.

4. Enter a default value in the Default Value box. The default values are used when the Unit Ventilator Controller is in the default

state. The Unit Ventilator Controller may enter the default state at startup. The state that the Unit Ventilator Controller enters at startup is selected during commissioning.

LX Series Unit Ventilator Controller User's Guide 71

Heating-Cooling Configuration

On the heating-cooling configuration screen, you define:

• occupied, standby, and unoccupied setpoints in both heating and cooling mode

• maximum and minimum discharge temperatures

• economize maximum outdoor temperature and enthalpy

• change over delay

• mechanical cooling minimum operating times (Figure 32)

LX Series Unit Ventilator Controller User's Guide72

Optimum Start

Optimum Start prepares the space for occupancy in advance of the occupied period. The Unit Ventilator Controller uses stored daily statistics to calculate the length of time required each day to reach the occupied setpoints just as actual occupancy begins.

See the primary Optimum Start section for more information. Note: For Optimum Start to work, the network variable nviOccCmd must be set

to SNVT type SNVT_tod_event. You can set this using the Changeable Nv Manager view of the device in FX Workbench.

Figure 32: Heating-Cooling Configuration Screen

Table 16: Heating-Cooling Configuration Parameters

Field Description

Heating Occupied/Bypass Standby Unoccupied Maximum Discharge

Temperature Minimum Heating

Time

LX Series Unit Ventilator Controller User's Guide 73

Displays the heating setpoint for the occupied and bypass states. Displays the heating setpoint for the standby state. Displays the heating setpoint for the unoccupied state. Displays the highest discharge air temperature you allow during the

heating state. Displays the length of time that the duct and perimeter heating must stay

ON once it has turned ON, and the length of time that the heating must stay OFF once it has turned OFF. Minimum heating time affects duct heating, perimeter heating, and staged outp ut s. Once a st ag ed outp ut has changed state, the next staged output cannot change state until the minimum heating time has passed.

Note:

Minimum Heating Time does not apply to modulated heating.

Table 16: Heating-Cooling Configuration Parameters

Field Description

T urn ON Heat Stage 1 before using Modulated Heating

Cooling Occupied/Bypass Standby Unoccupied Minimum Discharge

Temperature Mechanical Minimum Time ON Minimum Time OFF Minimum Outdoor

Temperature

Switch Over Delay

Economizer Maximum Outdoor

Temperature

Maximum Outdoor Enthalpy

Heat/Cool Change Over Heat/Cool Change

Over

This option normally applies to a situation where a gas-heating system needs to energize a contact before modulating the gas-heating valve.

Enter the cooling setpoint for the occupied and bypass states. Enter the cooling setpoint for the standby state. Enter the cooling setpoint for the unoccupied state. Enter the minimum temperature of the discharge air that you allow during

the cooling state.

Enter the minimum ON time for both heating and mechanical cooling. Enter the minimum OFF time for mechanical heating and cooling. Enter the minimum outdoor air temp erature at w hich mechanical co oling is

allowed. Mechanical cooling disables when the outdoor air temperature is less than this value.

The time interval that must pass before m echanical cooling ca n occur after free cooling or free cooling can occur after mechanical cooling.

Enter the value below which free cooling is permitted when only the outdoor air temperature is available and not the outdoor humidity or enthalpy.

Enter the value below which free cooling is permitted when only the outdoor air enthalpy, and not the indoor air enthalpy, is available.

The time interval that must pass before heating can occur after cooling or cooling can occur after heating.

Fan-Valve Configuration

On this screen, you select the type of fan input, fan operation, and floating valve operating properties (Figure 33).

LX Series Unit Ventilator Controller User's Guide74

Figure 33: Fan-Valve Configuration Screen

Table 17: Fan-Valve Configuration Parameters

Field Description

Fan Fan Speed Allows your sensor to measure the fan speed. Fan Current Allows your sensor to measure the current

drawn by the fan.

Current Threshold Sets the current at which you consider the fan

Minimum Speed Displays the fan minimum speed. ON/OFF Period Displays the period of time that must pass

Always ON in Occupied Mode Forces the fan to run continuously during

Digital Valves Minimum ON/OFF Period Displays the period of time that must pass

Valve Minimum Position Displays the valves, minimum position when

Drive Time for Floating Valves Displays the period of time required for the

to be ON. This affects the alarm that compares the states of the fan input and fan output.

before the fan can turn ON after turning OFF; or the fan can turn OFF after turning ON.

occupied mode. If this box is not checked, the fan runs only when there is a heating or cooling demand.

before the fan can turn ON after turning OFF, or the fan can turn OFF after turning ON.

there is a heating or cooling demand. The valves are fully closed when there is no heating or cooling demand.

valve to move from the fully closed to the fully open position.

LX Series Unit Ventilator Controller User's Guide 75

PID Configuration

The Unit Ventilator Controller uses as many as five PID Loops to control the space temperature, discharge temperature, CO2 level, and humidity.

Figure 34: The PID Configuration Screen

Table 18 applies to the space temperature, discharge temperature, CO2 level, and humidity loops.

Table 18: PID Configuration Parameters

Field Description

Proportional Gain Enter the gain per unit of the error. Integral Gain Enter the gain per unit of the error. Integral Time Enter the error repetitively sampled, and the integral gain is added to the

output. The period of time between samples is the integral time. Enter the integral time for your process.

Derivative Gain Enter the gain per unit of the error. Derivative Time Enter the derivative time–the time between two samples of the error. The

Deadband Enter a number to define the size of the deadband. The deadband is a

Use Supply Air Temperature Only for Limitation

two samples are compared to find the change in the error.

range of values symmetrical about the setpoint. See the Deadband section for more information.

Allows the Unit Ventilator Controller to control the unit with the room demand, and limits the discharge temperature between the minimum and maximum discharge temperature.

If this option is unchecked, the Unit Ventilator Controller tries to maintain the calculated discharge temperature setpoint. The discharge setpoin t is calculated with a linear equation between the minimum and maximum discharge air temperature and the space PID loops.

LX Series Unit Ventilator Controller User's Guide76

Alarm Configuration

On this screen, you can set the alarm high and low limits, offset, and alarm delays (Figure 35).

Figure 35: Alarm Configuration

Alarms monitor network variables or control points. These variables or points are called monitored variables. When a monitored variable has a value that causes an alarm message to be transmitted, then the monitored variable is in the alarm state.

Table 19 describes the alarm configuration parameters.

Table 19: Alarm Configuration Parameters

Field Description

Alarm Delay Enter the length of time that an input must be in the alarm state before an alarm

sounds.

Alarm Offset Enter the amount of deviation from the setpoint that causes an alarm to sound. Alarm Low

Limit Alarm High

Limit

Enter a value at which the alarm becomes active. The alarm becomes active when the monitored variable falls below this value.

Enter a value at which the alarm becomes active. The alarm becomes active when the monitored variable rises above this value.

Space and Return Temperatures and Humidity

Space and Return Temperature and Humidity alarms have an alarm delay and an alarm offset only. In this case, the alarm becomes active when both of the following conditions are present:

• The monitored temperature is outside of the range bounded by the setpoint plus

or minus the alarm offset.

LX Series Unit Ventilator Controller User's Guide 77

• This preceding condition exists for a length of time greater than the alarm delay.

CO2 Levels

While this alarm uses an offset, the alarm only sounds when the following conditions are present:

• The CO2 concentration is greater than the setpoint + the offset.

• This preceding condition persists for a length of time greater than the alarm delay.

An alarm does not sound when the CO2 concentration is less than the setpoint - the offset.

Discharge Temperature and Auxiliary Alarm

Both the Discharge Temperature and Auxiliary alarms have an alarm delay and high and low limit. In this case, the alarm becomes active when both of the following occur:

• The monitored temperature is outside of the range marked by the high and low limits.

• This preceding condition exists for a length of time greater than the alarm delay.

Mixed Air Temperature

Mixed air temperature alarm protects the cooling coils from freezing. The alarm becomes active when both of the following conditions are present:

• The monitored temperature is less than the low limit.

• This condition exists for a length of time greater than the alarm delay.

Fan Alarm

The Fan alarm applies to the fan state only. The fan alarm becomes active when one of following conditions occurs for a time period greater than the alarm delay:

• The fan command is ON, and the fan input differs from the fan output, or the fan current is lower than the fan current threshold, or

• The fan command is OFF, and the fan input differs from the fan output, or the fan current is higher than the fan current threshold.

Whether a digital fan speed is ON or OFF, a decision is made by monitoring the fan speed or fan current. The alarm delay must be long enough to allow the fan to reach the ON or OFF stage. The fan speed or fan current level is set in the Fan-Valve Configuration screen.

LX Series Unit Ventilator Controller User's Guide78

Similarly, a variable speed fan requires time to speed up or slow down so that its speed matches the output. The alarm delay must be long enough to allow the fan to reach its commanded speed; otherwise, false alarms generate.

General Settings Configuration

Figure 36 shows the General Settings Configuration screen.

Figure 36: General Settings Configuration Screen

Table 20: General Settings Parameters

Field Description

Fresh Air Minimum Input

Damper Position Select the Damper Position and enter a percentage value in the box

Air Volume Select Air Volume and enter a percentage to for a minimum amount

Damper Drive Time Enter the time required for the damper drive to move the damper

Select either Damper Position or Air Volume. If you are not using the fresh air damper, the minimum input area is not applicable and remains in gray text.

below Minimum Input. The percentage value sets the minimum fresh air intake. The damper opens as least as much as that value during occupied mode. Fully open is 100% and fully closed is 0%.

of fresh air. The fresh air minimum is calculated using return air temperature, mixed air temperature, and outside air temperature.

from fully open to fully closed.

LX Series Unit Ventilator Controller User's Guide 79

Table 20: General Settings Parameters

Field Description

Terminal Load Output Type

Bypass Time Enter the bypass time. Bypass time is the duration of bypass mode

Limit Enter the maximum CO2 concentration that will occur before the UV

Emergency Contact Input Action

Mixed Air Temperature Low Limit

Select either option to include or exclude the economizer in the terminal load calculations. If the economizer is not included, the fresh air dampers modulate first; and when they are fully open, the terminal load is calculated from 0. This is used for power consumption monitoring. See Terminal Load section.

which begins when the bypass button is pressed in unoccupied or standby mode. Remember that bypass time does not limit a bypass period commanded by nviOccCmd.

allows fresh air into the duct . Select the action to occur when the emergency contact is closed-

emergency purge or emergency shutdown. See the Emergency Operation section for more information on these modes.

Enter the lowest temperature that you allow the mixed air to reach. Mixed air temperature low limit is used to control the fresh air damper.

If a CO works to maintain low CO minimum temperature. For more information see Figure 15.

sensor is used to control the fresh air damper, the controller

concentrations while keeping the

Radiation Heating

Radiation heating provides you with the ability to start heating outputs without starting the heat pump fan. Hot air mixes with the room air by natural convection. When you are not using the heating outputs, the option appears as gray text. Table 21 provides further information on Radiation Heat parameters.

Table 21: Radiation Heat Parameters

Field Description

Permit Valve Radiation Heating

Permit Local Radiation Heating

Heat Order During Unoccupied Mode

When selected, it enables the valve heating outputs to start on a heating demand before the fan starts. If this option is not selected, and the fan is not ON, the valve heating outputs remain OFF.

When selected, it enables the local heating outputs to start on a heating demand before the fan starts. If this option is not selected, and the fan is not ON, the local heating outputs remain OFF.

This enables you to select your unoccupied heating order: Radiation First, Ventilation Only.

If you select Radiation First, the valve and/or heating outputs start first on a heating demand. If the option Ventilation Only is selected, the fan must be ON in order to start any heating outputs.

LX Series Unit Ventilator Controller User's Guide80

Options Configuration

On the Options Configuration screen (Figure 37) you can perform the following tasks:

• Configure Optimum Start

• Configure Humidity Control

• Enable Frost Protection

Figure 37: Options Configuration Screen

Optimum Start

Optimum Start prepares the space for occupancy in advance of the occupied period. The UVC uses stored daily statistics to calculate the length of time required each day to reach the occupied setpoints just as actual occupancy begins.

Optimum Start is described in the Optimum Start section. Note: For Optimum Start to work, the network variable nviOccCmd must be set

to SNVT type SNVT_tod_event. Use the Changeable Nv Manager view of the device in FX Workbench to change the SNVT type.

LX Series Unit Ventilator Controller User's Guide 81

Table 22: Options Configuration

Field Description

Maximum Start Time Set the maximum length of time before the start of occupancy

Enable Optimum Start for Heating

Enable Optimum Start for Cooling

Use Maximum Start Time if No Statistics

mode that the Unit Ventilation Controller can start to heat or cool the space.

Allow the Unit Ventilation Controller to heat the space so that the space temperature is within the occupied setpoints when the occupied period begins.

Allow the Unit Ventilation Controller to cool the space so that the space temperature is within the occupied setpoints when the occupied period begins.

Allow the Unit Ventilation Controller to use the maximum start time as the length of time needed to heat or cool the space before occupancy. Once Optimum Start statistics have been recorded, the LX-UVL Controller uses Optimum Start time periods calculated from the statistics. The Maximum Start Time is only used to limit the length of the Optimum Start Time.

Bit 58 of the UCPTobject Options when set enables this option. If this box is not selected, the Unit Ventilation Controller begins to heat or cool the space at the beginning of the occupied period.

After the first start, it heats or cools the space at the recorded Optimum Start time. After the second start, it heats or cools the space at the calculated Optimum Start time.

Frost Protection

Select the Frost Protection box to have the heat turned ON at a space temperature of 43°F (6°C) and turned off at 46°F (8°C). The heat can turn ON independently of the temperature control. For example, the heat turns ON when nviApplicMode is set to HVAC_OFF.

The heat turns ON in the order determined by the heating order.

Humidity Control

You can control Humidity many ways in the Unit Ventilation Controller; with a cooling coil, a humidifier or a dehumidifier. Table 23 describes the Humidity Control.

Table 23: Humidity Control

Field Description

Setpoint Enter the space humidity setpoint in percent. Humidifier/Dehumidifier

Minimum ON/OFF Time

Enable Dehumidifying Cycle Enables the dehumidifier using the cooling coil. Disable in Heating Mode Disables the dehumidifier using the cooling coil in heating

Enter the period of time that must pass before the humidifier or dehumidifier can turn ON after turning OFF, or turn OFF after turning ON. Note: Humidifier/Dehumidifier ON/OFF time does not apply to

modulated humidifier and dehumidifier outputs.

mode.

LX Series Unit Ventilator Controller User's Guide82

Table 23: Humidity Control

Field Description

Cooling Override Valu e Enter the minimum value for the cooling internal control loop. In

Fan Speed Override Value Enter the value for the fan speed in dehumidification mode. If

dehumidification process, this is the smallest value for the cooling outputs. For example, if you have one modulating cooling valve and the value for the cooling override is 55%, the valve always opens at 55% or more in dehumidification mode.

you have 3 fan speeds, and you want speed 2 to be open, enter the value 66.66%, which corresponds to 2 fan speeds on a 3 fan speed possibility (2/3).

Network Input Configuration

Figure 38 shows the network input configuration screen. Table 24 describes the parameters.

Figure 38: Network Input Configuration Screen

Table 24: Network Input Parameters

Field Description

Heartbeat Sets the maximum time between updates for the associated network input.

Persistent Allows the network variable to remain in memory after a power failure and/or

When the heartbeat interval has passed without an update, the network input enters the heartbeat failure state, and its value becomes invalid.

reset. Do not make frequently changing network variables persistent.

Heartbeat Alarms

An alarm occurs if the period between received values of these variables exceeds the value you enter into the Heartbeat column. For more information, see the

Alarm Operation

LX Series Unit Ventilator Controller User's Guide 83

section.

Network Output Configuration

The network outputs screen enables you to control network traffic to reduce network congestion while transmitting data as quickly as is necessary for your application.

The network outputs screen enables you to control the frequency of network variable transmissions through several different parameters. On the Network Outputs Configuration screen, you can configure:

• heartbeat period for network outputs

• Send on Delta quantity

• throttle settings for several network outputs

You can also set the maximum send time and minimum send time for all other network variables (Figure 39).

Figure 39: Network Output Configuration Screen

LX Series Unit Ventilator Controller User's Guide84

Table 25: Network Output Configuration Parameters

Field Description

Heartbeat The maximum time period betwee n transmissions of the network

Send on Delta Enter the amount of change of the value of the network variable that

Throttle Enter the minimum time period that must pass before a network variable

General The values entered in the General box affect all other network variables

Maximum Send Time Enter the maximum time between transmissions of network variables. Minimum Send Time Enter the minimum time between transmissions of network variables.

variable.

must occur before the variable is transmitted. The network variable is transmitted whenever this much change occurs.

is transmitted.

not listed here.

Object Manage

The Object Manage screen enables you to view the status of the LONMARK object and to use the LONMARK commands. To use the Object Manage screen, you must configure the Unit Ventilator Controller and have it online and in communication with the FX supervisory controller (Figure 40). Table 26 describes the parameters.

Figure 40: Object Manage

Object Status

Object Status messages are listed in the following sections with references to tables describing the causes.

LX Series Unit Ventilator Controller User's Guide 85

Table 26: Object Manage Parameters

Field Description

Device State Displays the current state of the LONMARK object. Object Status Displ ays information from nvoUnitStatus. Messages, such as

Display Active Only If the box Display Active Only is selected, only the red active status

Get Status Refreshes status information for devices in the Object Status pane. Clears Status Clears all status flags. This removes all messages. Clicking Get Status

Override ON Places the Unit Ventilator Controller into the override state. Control

Override OFF Ends controller override. Enable Enables the controller after an override. Disable Sets the L

Request Allows advanced users to query the LONMARK using the LONMARK

Communications Failure or Electrical Fault, may be displayed here. A red icon indicates an active state and a gray icon indicates an inactive state.

flags are shown. The Object Status area is blank when the UV is in its normal state.

For a description of each of the Object Status pane messages, see

Object Status

retrieves new information. This can be used to check if a problem condition is solved.

outputs including the network variables and linked hardware outputs are set to their configured override value or state.

control outputs are at their configured disabled state.

object and commands. To query the L Select a command from the drop-down list beside the request button. Click the Request button. Requests are handled by SNVT_obj_request. Values for this SNVT

are given in Table 27.

ONMARK object to the disabled mode. In the disabled mode,

ONMARK object:

Table 27: Values for SNVT_obj_request

Value Identifier Meaning

0 RQ_NORMAL Enable object and remove override. 1 RQ_DISABLED Disable object. 2 RQ_UPDATE_STATUS Report object status. 3 RQ_SELF_TEST Perform object self test. 4 RQ_UPDATE_ALARM Update alarm status. 5 RQ_REPORT_MASK Report status bit mask. 6 RQ_OVERRIDE Override object. 7 RQ_ENABLE Enable object. 8 RQ_RMV_OVERRIDE Remove object override. 9 RQ_CLEAR_STATUS Clear object status. 10 RQ_CLEAR_ALARM Clear object alarm. 11 RQ_ALARM_NOTIFY_ENABLED Enable alarm notification. 12 RQ_ALARM_NOTIFY_DISABLED Disable alarm notification.

LX Series Unit Ventilator Controller User's Guide86

Table 27: Values for SNVT_obj_request

Value Identifier Meaning

13 RQ_MANUAL_CTRL Enable object for manual control. 14 RQ_REMOTE_CTRL Enable object for remote control. 15 RQ_PROGRAM Enable programming of special configuration

16 RQ_CLEAR_REST Clears the bit that indicates that the object has

17 RQ_RESET Resets the object.

1. Not all commands are available in the Unit Ventilator Controller.

properties.

been previously reset.

Communication Failure

This message results from a heartbeat failure on a network variable input that sets the comm_failure bit of nvoStatus. See Table 11.

Electrical Fault

This message indicates that a local hardware sensor is disconnected. The disconnect condition sets the electrical_fault bit of nvoStatus. See Table 12 for a list of the possible disconnected sensors.

Out of Limits

This message indicates that a monitored point has exceeded limits set by the operator who configured the device. The out-of-limits sets the out_of_limits bit of nvoStatus. See Table 14.

Disabled

Active if you have disabled the device by pressing the Disable button.

In Alarm

Active if a communications failure or electrical fault has occurred or if any of the conditions in the Alarm Configuration window have been met.

In Override

Active if you have placed the device into override by pressing the Override button.

Out of Service

Active when the UV controller cannot control the temperature in the zone of control because it is not receiving a space temperature, or there is no slave input (nviSlave).

Network Variables

The following text describes some of the most commonly used network variables found in the Unit Ventilator Controller.

LX Series Unit Ventilator Controller User's Guide 87

nviApplicMode

You can use this network variable input to coordinate the Unit Ventilator Controller with the following devices:

• air handler controller

• any other supervisory controller

• human interface device

Type: SNVT_hvac_mode (108)

Table 28: nviApplicMode

Value Identifier Notes

0 HVAC_AUTO Controller automatically changes between appl ication

1 HVAC_HEAT Heating only. 2 HVAC_MRNG_WRMUP Application-specific morning warm up. 3 HVAC_COOL Cooling only. 4 HVAC_NIGHT_PURGE Application-specific night purge. 5 HVAC_PRE_COOL

6 HVAC_OFF Controller not controlling outputs. 7 HVAC_TEST

8 HVAC_EMERG_HEAT 9 HVAC_FAN_ONLY Air not conditioned, fan turned on.

10 HVAC_FREE_COOL 11 HVAC_ICE 0xFF HVAC_NUL Value not available.

modes.

Application-specific pre-cool

Equipment being tested Emergency heat mode

Cooling with compressor not running

Ice-making mode

1. Not supported in the Unit Ventilator Controller.

nviCO2

Transmits CO2 level from a network device to the Unit Ventilator Controller. Network values have priority over local sensor values.

Type: SNVT_ppm (29)

nviDischargeTemp

Transmits discharge temperature from a network device to the LX-UVL-1. Network values have priority over local sensor values.

Type: SNVT_temp_p (105)

nviEconoEnable

This network variable input receives the economizer enable demand. When the state and value are not set to zero, the economizer is enabled. When the state or value is set to zero, the water state is disabled.

Type: SNVT_hvac_emerg

LX Series Unit Ventilator Controller User's Guide88

nviEmergCmd

Use this network variable input to command the UVC into different emergency modes. It is typically set by a supervisory node. See Table 29.

Type: SNVT_hvac_emerg (103)

Table 29: nviEmergCmd

Value Identifier Actions

0 EMERG_NORMAL Normal operation.

1 2 3 EMERG_PURGE The damper moves to the fully open posi tion.

4 EMERG_SHUTDOWN Fan, heating, and cooling are turned OFF. 5

0xFF EMERG_NUL Value not available.

1. Not supported in the Unit Ventilator Controller.

EMERG_PRESSURIZE EMERG_DEPRESSURIZE

EMERG_FIRE

The damper moves to the fully open position.

The damper moves to the fully closed position.

Fan, heating, and cooling are turned OFF.

---

nviExtCmdOutputx

These are numbered following the output number. For example,

nvoExtCmdOutput1, nvoExtCmdOutput2,.... These network variable inputs

receive the output signal, whether state and percentage to control any output that is unassigned and configured through the actuator configuration wizard.

Type: SNVT_switch (95)

nviFanSpeedCmd

This network variable input receives the fan speed demand. It receives a value between 0–100% and a state 0–1. If, for example, you have 3 fan speeds, fan speed 1 starts over 33%, fan speed 2 starts over 66% and fan speed 3 starts over 100%. To start, the field state must be ON (1).

Type: SNVT_switch (95)

nviFanState

This network variable input receives the fan state. When state and value are not set to zero, the fan state is considered ON. When state or value is set to zero, the fan state is considered OFF.

Type: SNVT_switch (95)

LX Series Unit Ventilator Controller User's Guide 89

nviHotWater

This network variable input receives the water state. Water state refers to whether the water is hot or cold.

When state and value are not set to zero, the water state is hot. When state or value is set to zero, the water state is cold.

Type: SNVT_switch (95)

nviMixedAirTemp

Used to receive the mixed air temperature. Network values have priority over local sensor values.

Type: SNVT_occupancy (109) or SNVT_tod_event (128)

nviOccCmd and nviOccManCmd

This network variable input is used to command the Unit Ventilator Controller object into different occupancy modes. See the Mode Selection section for more information. Table 30 shows the possible values of nviOccCmd and nviOccManCmd.

Type: SNVT_occupancy (109) or SNVT_tod_event (128)

Table 30: Values of nviOccCmd and Modes

Value Identifier Unit Ventilator Controller Mode

0 OC_OCCUPIED Occupie d Mode 1 OC_UNOCCUPIED Unoccupied mode 2 OC_BYPASS Bypass mode 3 OC_ST ANDBY S tandby mode 0xFF OC_NUL Invalid data

The network variable nviOccCmd commands the Unit Ventilator Unit Controller to change modes according to the value of the variable. The value of nviOccCmd itself can be changed by a network schedule or a manual change.

While in any mode, the UVC can enter a heating or cooling state as required to maintain the space within the limits of the setpoints.

nviOutdoorEnth

Used to receive the outdoor enthalpy. Network values have priority over local sensor values.

Type: SNVT_enthalpy (153)

nviOutdoorRH

Used to receive the outdoor air humidity. Network values have priority over local sensor values.

Type: SNVT_lev_percent (81)

LX Series Unit Ventilator Controller User's Guide90

nviOutdoorTemp

This network variable input receives the outdoor air temperature. Type: SNVT_temp_p (105)

nviReturnTemp

Transmits return temperature from a network device to the UV. Network values have priority over local sensor values.

nviSetPoint

Use this network variable input to change the temperature setpoints for the occupied and standby modes via the network. The individual heating and cooling setpoints for the occupied and standby modes are calculated from nviSetPoint. See the The Effect of nviSetPoint on the Active Setpoints section.

Type: SNVT_temp_p (105)

nviSetPointOffset

Use this network variable input to shift the temperature setpoint by adding the value of nviSetpointOffset to the current setpoint. This network variable operates only on occupied and standby setpoints and does not affect the unoccupied setpoint. See the The Effect of nviSetPoint on the Active Setpoints section.

Type: SNVT_temp_p (105)

nviShedding

Use this network variable input to reduce the Unit Ventilator Controller power consumption. For example, if nviShedding is set to 25%, then heating and cooling do not exceed 75%.

Type: SNVT_lev_percent (81)

nviSlave

Use this network variable input to force the Unit Ventilator Controller to follow the demands of another unit ventilation controller. It is normally bound to the nvoUnitStatus of the other Unit Ventilator Controller.

Type: SNVT_hvac_status (112)

nviSpaceEnth

Transmits space enthalpy from a network device to the UV. Network values have priority over local sensor values.

Type: SNVT_enthalpy (153)

LX Series Unit Ventilator Controller User's Guide 91

nviSpaceRH

This network variable input transmits space humidity from a network device to the UVC. Network values have priority over local sensor values.

Type: SNVT_lev_percent (81)

nviSpaceTemp

Transmits space temperature from a network device to the Unit Ventilator Controller. Network values have priority over local sensor values.

Type: SNVT_temp_p (105)

nviWaterTemp

Transmits water temperature from a network device to the Unit Ventilator Controller. Network values have priority over local sensor values. If both nviHotWater and nviWaterTemp are received from the network, nviHotWater has priority over the nviWaterTemp.

Type: SNVT_temp_p (105)

nvoCtrlOutputx

These are numbered following the output number. For example, nvoCtrlOutput1, nvoCtrlOutput2. These network variable outputs send the output signal, whether state or percentage, to any actuators.

Type: SNVT_switch (95)

nvoDischargeSetPt

This network variable output sends the discharge setpoint in use by the unit ventilator object.

Type: SNVT_temp_p (105)

nvoEconoEnable

This network variable output is used to monitor or send the enable or disable status of the economizer. Economizer control is enabled when st ate and value fields are 1 and 100%, respectively . Economizer control is disabled when state and value fields are set to zero.

Type: SNVT_switch (95)

nvoEffectSetPt

This network variable output sends the effective setpoint in use by the fan coil object.

Type: SNVT_temp_p (105)

LX Series Unit Ventilator Controller User's Guide92

nvoFanSpeed

This network variable output sends the fan speed. Type: SNVT_switch (95)

nvoHwInputx

Numbered following the input number . For example, nviHwInput1, nvoHwInput2. The network variable output sends the input value over the network with their own changeable SNVT type.

Type: Changeable

nvoOccState

This network variable output sends the occupancy state used by the unit ventilator object.

Type: SNVT_occupancy (109)

nvoUValarm

Table 31 describes the nvoUValarm parameters. Type: SNVT_state_64 (165) Format: UNVT_uv_alarms

Table 31: nvoUValarm (Part 1 of 3)

Programmatic Name Bit

Number

nviSpaceTempHeartBeat 0 Heartbeat failure reported from nviSpaceTemp. nviApplicModeHeartBeat 1 Heartbeat failure has occurred in nviApplicMode. nviSetPtOffsetHeartBeat 2 Heartbeat failure has occurred in nviSetPtOffset. nviOccCmdHeartBeat 3 Heartbeat failure has occurred in nviOccCmd. nviWaterTempHeartBeat 4 Heartbeat fa ilure has occurred in nviWaterTemp. nviHotWaterHeartBeat 5 Heartbeat failure has occurred in nviHotWater.

nviSupplyTempHeartBeat 6 Heartbeat failure has occurred in nviSupplyTemp. nviFanStateHeartBeat 7 Heartbeat failure has occurred in

nviEconEnableHeartBeat 8 Heartbeat failure has occured in nviEconEnable. nviSheddingHeartBeat 9 Heartbeat failure has occurred in nviShedding. nviSlaveHeartBeat 10 Heartbeat failure has occurred in nviSlave. nviOutdoorTempHeartBeat 11 Heartbeat failure has occurred in nviOutdoorTemp. nviSpaceRHHeartBeat 12 Heartbeat failure has occurred in nviSpaceRH. nviOutdoorRHHeartBeat 13 Heartbeat failure has occurred in nviOutdoorRH. nviCO2HeartBeat 14 Heartbeat failure has occurred in nviCO2. nviReturnTempHeartBeat 15 Heartbeat failure has occurred in nviReturnTemp. nviMixAirTempHeartBeat 16 Heartbeat failure has occurred in nviMixAirTemp. nviSpaceEnthHeartBeat 17 Heartbeat failure has occurred in nviSpaceEnth.

Meaning When Bit Is Set

This network variable input transmits the water state: hot or cold.

nviFanSpeedCmdState.

LX Series Unit Ventilator Controller User's Guide 93

Table 31: nvoUValarm (Part 2 of 3)

Programmatic Name Bit

Number

nviOutdoorEnthHeartBeat 18 Heartbeat failure has occurred in nviOutdoorEnth. nviFanSpeedCmdHeartBeat 19 Heartbeat failure has occurred in

nviExtCmdOutputxHeartBeat 20-26 Heartbeat failure has occurred in

SpaceTempSensorFault 32 Space temperature sensor is disconnected for

DischargeTempSensorFault 33 Discharge temperature sensor is disconnected for

ReturnTempSensorFault 34 Return temperature sensor is disconnected for

MixedAirTempSensorFault 35 Mixed air temperature sensor is disconnected for

OutdoorTempSensorFault 36 Outdoor temperature sensor is disconnected for

WaterTempSensorFault 37 Water temperature sensor is disconnected for

SetpointOffsetElecFault 38 Setpoint offset is disconnected for longer than

LowSpaceTemp 39 Space temperature is lower than the active heating

HighSpaceTemp 40 Space temperature is higher than the active

LowDischargeTemp 41 The discharge temperature is lower than the low

HighDischargeTemp 42 The discharge temperature is higher than the high

LowReturnTemp 43 The return temperature is lower than the active

HighReturnTemp 44 The return temperature is higher than the active

LowMixedAirTemp 45 The mixed air temperature is lower than the low

LowSpaceRH 46 The space humidity is lower than a setpoint by

HighSpaceRH 47 The space humidity is higher than a setpoint by

Meaning When Bit Is Set

nviFanSpeedCmd.

nviExtCmdOutput.

longer than 30 seconds.

30 seconds.

setpoint by more than the offset for a time period longer than the alarm delay.

heating setpoint by more than the offset for a time period longer than the alarm delay.

limits setpoint for a time period longer than the alarm delay.

heating setpoint by more than the offset and for longer than the time specified in the alarm delay.

cooling setpoint by more than the offset and for longer than the time specified in the alarm delay.

limit setpoints for longer than the time specified in the alarm delay.

more than the humidity offset for a time period longer than the alarm delay.

more than humidity offset for a time period longer than the alarm delay.

LX Series Unit Ventilator Controller User's Guide94

Table 31: nvoUValarm (Part 3 of 3)

Programmatic Name Bit

Number

HighCO2Level 48 The CO2 concentration is higher than the CO2 limit

FanStateMismatch 49 The fan state is different than the fan output for a

AuxiliaryLowAlarm 50 The auxiliary alarm input is lower than the low limit

AuxiliaryHighAlarm 51 The auxiliary alarm input is higher than the low limit

Emergency 52 The Heat Pump Unit Controller is in emergency

Meaning When Bit Is Set

by more than the amount defined in any CO and for longer than the time defined in the alarm

delay.

time period longer than the alarm delay.

setpoint for a time period longer than the alarm delay.

mode.

nvoUVstate

This network variable output sends the unit ventilator status. It provides the configuration errors and mode status.

Type: SNVT_state_64 (165)

offset

Format: UNVT_uv_state

Table 32: nvoHPstate (Part 1 of 2)

Programmatic Name Bit

Number

OutofService 0 The device is out of service. There is no space

EmergencyMode 1 Emergency mode is ON. It is received from the

HotWater 2 The water is hot. EconomizerEnabled 3 Economizer is enabled. This occurs when the

MecCoolingEnabled 4 Mechanical cooling is enabled. This occurs when

CtrlOutputxOverridden 8–14 The unit ventilator object output is overridden. HwOutputxOverridden 15–21 The hardware output is overridden. DupReturnTempCfgError 36 Duplicate return air temperature sensor

DupDischrgTempCfgError 37 Duplicate discharge air temperature sensor

DupOutTempTempCfgError 38 Duplicate outdoor air temperature sensor

DupMixAirTempCfgError 39 Duplicate mixed air temperature sensor

DupWaterTempCfgError 40 Duplicate water temperature sensor configuration

Meaning When Bit Is Set

temperature sensor configured, or nvislave is not bound.

nviEmergCmd or sent by the emergency contact.

outdoor temperature is lower than the economizer maximum outdoor temperature.

the outdoor temperature is higher than the mechanical minimum outdoor temperature.

configuration error.

error.

LX Series Unit Ventilator Controller User's Guide 95

Table 32: nvoHPstate (Part 2 of 2)

Programmatic Name Bit

Number

DupSpaceHumidCfgError 41 D uplicate space humidity sensor configuration

DupOutHumidCfgError 42 Duplicate outdoor humidity sensor configuration

DupSpaceEnthCfgError 43 Duplicate space enthalpy sensor configuration

DupOutEnthCfgError 44 Duplicate outdoor enthalpy sensor configuration

DupCO2LevelCfgError 45 Duplicate CO2 level sensor configuration error. DupAuxAlarmCfgError 46 Duplicate auxiliary alarm sensor configuration

DupFanStateCfgError 47 Duplicate fan state sensor configuration error. DupFanSpdSelCfgError 48 Duplicate fan speed selector sensor configuration

DupModeSelCfgError 49 Duplicate mode selector sensor configuration

DupOccCntctCfgError 50 Duplicate occupancy contact sensor configuration

DupBypassCntctCfgError 51 Duplicate bypass contact sensor configuration

DupWindowCntctCfgError 52 Duplicate window contact sensor configuration

DupEconoCntctCfgError 53 Duplicate economizer enabled contact sensor

DupEmergCntctCfgError 54 Duplicate emergency contact sensor configuration

FanSpeedCfgError 55 Fan speeds configuration error. NoFanOutputCfgError 56 No fan output configuration error. NoHeatOrCoolCfgError 57 No heat or cooling output configuration error. HeatValveCfgError 58 Heating valve configuration error. CoolValveCfgError 59 Cooling valve configuration error. HeatCoolValveCfgError 60 Heating and cooling valve configuration error. HeatStagesCfgError 61 Heating stages configuration error. CoolStagesCfgError 62 Cooling stages configuration error. RevValvWOCoolCfgError 63 Reversing valve without cooling stages

Meaning When Bit Is Set

error.

configuration error.

error.

configuration error.

nvoSpaceTemp

This network variable output sends the space temperature used by the fan coil object.

Type: SNVT_temp_p (105)

LX Series Unit Ventilator Controller User's Guide96

nvoTerminalLoad

This network variable output sends the energy demand of the fan coil in percentage. Positive values are cooling demand and negative values are heating demand.

Type: SNVT_lev_percent (81)

nvoUnitStatus

This network variable output sends the following simultaneously:

• operating mode

• primary heating state as a percentage

• secondary heating state (if relevant) as a percentage

• cooling state as a percentage

• fan state as a percentage

• unit ventilator alarm state Type: SNVT_hvac_status (112)

LX Series Unit Ventilator Controller User's Guide 97

Standard Network Variable Types (SNVTs)

The following are some of the SNVTs more commonly used in the Unit V entilator Controller configuration wizard.

SNVT_hvac_emerg (103)

HVAC Emergency Mode used for heating, ventilating, and air conditioning applications.

Table 33: SNVT_hvac_emerg

SNVT_hvac_emerg Description

SNVT Index 103 Measurement emerg_t Field Type Category Enumeration Type Size 1 byte Valid Type Range emerg_t Type Resolution 1 Units N/A Invalid Value EMERG_NUL Raw Range emerg_t Scale Factor N/A File Name SNVT_EM.H Default Value N/A

SNVT_hvac_mode (108)

Use for heating, ventilating, and air conditioning applications.

Table 34: SNVT_hvac_mode

SNVT_hvac_mode Description

SNVT Index 108 Measurement hvac_t Field Type Category Enumeration Type Size 1 byte Valid Type Range hvac_t Type Resolution 1 Units N/A Invalid Value HVAC_NUL Raw Range hvac_t Scale Factor N/A File Name SNVT_HV.H Default Value N/A

LX Series Unit Ventilator Controller User's Guide98

SNVT_hvac_status (112)

Use for heating, ventilating, and air conditioning applications.

Table 35: SNVT_hvac_status

SNVT_hvac_status Description

SNVT Index 112 Measurement HVAC Status Field Type Category Structure Type Size 12 bytes

Table 36: SNVT_hvac_status Structure

Field Measurement

mode hvac_t heat_output_primary signed long heat_output_secondary signed long cool_output signed long econ_output signed long fan_output signed long in_alarm unsigned short

Table 37: HVAC Status Mode

HVAC Status Mode Description

Field mode Measurement hvac_t Field Type Category Enumeration Type Size 1 byte Valid Type Range hvac_t Type Resolution 1 Units N/A Invalid Value HV_NUL Raw Range hvac_t Scale Factor N/A File Name SNVT_HV.H Default Value N/A

LX Series Unit Ventilator Controller User's Guide 99

Table 38: Primary Heat Output

Primary Heat Output Description

Field Heat_output_primary Measurement Primary Heat Output Field Type Category Signed Long Type Size 2 bytes Valid Type Range -163.840 – 163.830 Type Resolution 0.005 Units Percent of full scale Invalid Value 32,767 (0x7FFF) Raw Range -32,768 – 32,766

0x7FFE

Scale Factor 5, -3, 0

File Name N/A Default Value N/A

S = a*10b*(R+c)

Table 39: Secondary Heat Output

Secondary Heat Output Description

Field heat_output_secondary Measurement Secondary Heat Output Field Type Category Signed Long Type Size 2 bytes Valid Type Range -163.840 – 163.830 Type Resolution 0.005 Units Percent of full scale Invalid Value 32,767 (0x7FFF) Raw Range -32,768 – 32,766

0x7FFE

Scale Factor 5, -3, 0

File Name N/A Default Value N/A

S = a*10b*(R+c)

LX Series Unit Ventilator Controller User's Guide100

Johnson Controls LX Series User Manual

Specifications and Main Features

Frequently Asked Questions

User Manual

Introduction

Sensor Configuration Wizard

Control Features

LONMARK Functional Profile

Units in LONWORKS Networks

Language Selection

Selecting a Measurement System or Selecting a Language

Unit Ventilator Controller Installation Overview

Inputs

10k Ohm or Digital Input

Analog Inputs

4 to 20 mA Analog Input, Externally Supplied

Sensors and Switches

Auxiliary Alarm Input

Bypass Contact Input

CO2 Level Input

Discharge Temperature Input

Economizer Enable Input

Emergency Contact Input

Fan Speed Selector Input

Fan State Input

Mixed Air Temperature Input

Mode Selector

Occupancy Input

Outdoor Enthalpy Input

Outdoor Humidity Input

Outdoor Temperature Input

Return Air Temperature Input

Setpoint Offset Input

Space Enthalpy Input

Space Humidity Input

Space Temperature Input

Water Temperature Input

Window Contact Input

Outputs

Analog Output

Analog Output Protection

Digital Outputs

Staged Outputs

Output Selections

Fan Speed 1–3

Heating Outputs 1–4

Cooling Outputs 1–4

Reversing Valve

Humidifier and Dehumidifier Outputs

Minimum Fresh Air Enable (MIN_FRESH_AIR_ENABLE)

Economizer Enable

Heat Valve ON-OFF

Cool Valve ON-OFF

Heat Cool Valve ON-OFF

Heat Valve Open or Close

Cooling Valve Open or Close

Heat Cool Valve Open or Close

Fan Speed Modulate (FAN_SPEED_MOD)

Heating Modulate (HEATING_MOD)

Heating or Cooling Valve Modulate (HEATING_VALVE_MOD) (COOLING_VALVE_MOD)

Fresh Air Damper Modulate (FRESH_AIR_DAMPER_MOD)

Fresh Air Damper Open or Close

Mode Selection

Network Variables Used for Mode Selection

Occupied Mode

Starting Occupied Mode

Ending Occupied Mode

Unoccupied Mode

Starting Unoccupied Mode

Ending Unoccupied Mode

Bypass Mode

Starting Bypass Mode

Ending Bypass Mode

Standby Mode

Starting Standby Mode

Ending Standby Mode

Slave Mode

St ate Selection and Description

Supervisory Control and Scheduling

Calculating the Space Temperature Setpoint