Danfoss EXD 316 Data sheet
Data sheet
Superheat Controller
Type EXD 316
EXD 316 is a superheat controller for the stepper
motor valve that can be used where there are
requirements for accurate control of superheat in
connection with refrigeration.
The controller and valve can be used where
there are requirements for accurate control of
superheat in connection with refrigeration.
Applications:
• Processing plant (water chillers)
• Cold store (air coolers)
• A/C plant
• Heat pumps
• Air conditioning
Benets • The superheat is regulated to the lowest
possible value.
• The evaporator is charged optimally – even
when there are great variations of load and
suction pressure.
Main features
• Regulation of superheat
• MOP function
• ON/OFF input for start/stop of regulation
• Relay output to alarm
• Energy savings – the adaptive regulation of
the refrigerant injection ensures optimum
utilisation of the evaporator and thus a high
suction pressure.
• CANbus communication
• Safety features and
• Alarm indications
© Danfoss | DCS (sw) | 2017.01
DKRCC.PD.RT0.A1.02 | 1
Data sheet | Superheat controller type EXD 316
Contents Pages
Applications..................................................................................................................................................3
Function overview ..........................................................................................................................................3
Data ...........................................................................................................................................................4
Accessories ...................................................................................................................................................4
Ordering ......................................................................................................................................................4
Dimensions ..................................................................................................................................................4
Connections .................................................................................................................................................5
Conguration ................................................................................................................................................6
Installation ...................................................................................................................................................7
Data communication .......................................................................................................................................7
Installation sensors ..........................................................................................................................................8
Start of controller............................................................................................................................................9
Settings and checks to be made before start ............................................................................................................9
Op ........................................................................................................................................................... 10
Operation .................................................................................................................................................. 11
Types of regulation ........................................................................................................................................ 12
Manually operating the valve ............................................................................................................................ 13
Finding the optimum settings ........................................................................................................................... 14
If the superheat uctuates ............................................................................................................................... 14
Troubleshooting ........................................................................................................................................... 15
Alarms ...................................................................................................................................................... 15
Appendix I.................................................................................................................................................. 16
- Menu survey ............................................................................................................................................ 16
- Survey of functions .................................................................................................................................... 18
Appendix II ................................................................................................................................................. 21
- General information to CANbus communication via a PLC etc. ................................................................................. 21
- EXD 316 – Parameter identication (CANbus) ..................................................................................................... 22
Installation considerations ............................................................................................................................... 23
List of literature ............................................................................................................................................ 23
Acronyms and abbreviations used in this manual:
LOC Loss of charge indication
SH Superheat
MOP Maximum operating pressure
MSS Minimum stable superheat
PNU Parameter number
Te Saturated suction temperature
Pe Evaporator pressure
S2 Evaporator temperature
S4 Evaporator outlet temperature
OD Opening degree
EEV Electronic expansion valve
∆Tm Temperature dierence between media temperature and evaporating temperature
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EXD 316
Data sheet | Superheat controller type EXD 316
Applications
The following gives an idea of the application scope of the
EXD 316 controller.
Water chiller using direct expansion
The most common application is water chillers using direct
expansion. The regulation can be single loop using an AKS 32R
pressure transmitter to measure evaporator pressure and an S2
sensor to measure superheated gas. If double loop regulation is
used, the S4 sensor should be located at the water outlet pipe to
measure the leaving water temperature. It is recommended to
start with factory settings.
The application diagram shows the use of EXD 316 as a
superheat controller, where temperature sensor AKS 21A and
pressure transmitter AKS 32R have been shown as an example.
Function overview
Minimum Stable Superheat (MSS)
The controller will search for the minimum stable superheat
between an upper and lower boundry. If the superheat has been
stable for a period, the superheat reference is decreased. If the
superheat becomes unstable, the reference is raised again. This
process continues as long as the superheat is within the bounds
set by the user. The purpose of this is to search for the lowest
possible superheat that can be obtained while still maintaining a
stable system. The superheat reference can also be xed, in which
case this function is disabled.
Maximum Operating Pressure (MOP)
In order to reduce the strain of the compressor, a maximum
operating pressure can be set. If the pressure comes above this
limit, the controller will control the valve to provide a lower
pressure instead of a low superheat. The limit for this function
is usually a xed pressure, but it is possible to oset the limit
temporarily.
Stand-alone function
EXD 316 is designed to operate in conjunction with a system
master controller, which will control the EXD 316 via CANBUS or
analog signal. It is however possible to use it in a standalone mode
using one temperature and one pressure transducer.
Danfoss
84N386.10
Manual Control as a valve driver
The valve can be controlled manually by setting the desired
operating degree using CANBUS. Alternatively, the controller may
also be started and stopped externally using the analog signal 4 to
20 mA/0 to 10 V d.c., /1 to 5 V d.c.
Forced opening during startup
In some applications it is necessary to open the valve quickly when
the compressor turns on to prevent suction pressure becoming
too low. This is ensured by setting a xed opening degree and
a startup time for the controller. Note that this will give a xed
opening degree for the duration of the start time, regardless of the
superheat value.
Relay
The relay for the alarm function is an alternating relay. In the event
of an alarm, the relay will close, which may, for instance, be used
for an alarm buzzer.
Back-up Battery
For safety reasons the liquid ow to the evaporator must be cut
o if there is power failure for the controller. As the ETS valve is
provided with step motor, it will remain open in such a situation.
When mounting the battery backup, the valve will close in the
event of a power cut.
© Danfoss | DCS (sw) | 2017.01
DKRCC.PD.RT0.A1.02 | 3
Data sheet | Superheat controller type EXD 316
Data
Compatible valves ETS / CCM / CCMT 0 - 42 / CTR / ETS 6
Supply voltage
Power consumption
Input signal
*)Ri: mA: 400 ohm
V: 50 kohm
Sensor input 2 pcs. Pt 1000 ohm
Alarm relay 1 pcs. SPDT
Step motor output Pulsating 30 - 300 mA
Data communication Via CANbus
Environments
Enclosure IP 20
Weight 300 g
Montage DIN rail
Operation Via CANbus
Approvals
24 V AC / DC +/-15% 50/60 Hz, 10 VA
(the supply voltage is not galvanically
separated from the input and output signals)
Controller
ETS step motor
Current signal * 4-20 mA or 0-20 mA
Voltage signal * 0-10 V or 1-5 V
Pressure transmitter AKS 32R
Digital input from external contact function
0 to +55°C, during operations
-40 to +70°C, during transport
20 - 80% Rh, not condensed
No shock inuence/vibrations
EU Low Voltage Directive and EMC demands re.
CE-marking complied with.
LVD-tested acc. to EN 60730-1 and EN 60730-2-9
EMC-tested acc. to EN50081-1 and EN 50082-2
5 VA
1.3 VA
AC-1: 4 A (ohmic)
AC-15: 3 A (inductive)
Ordering
Type Function Code no.
EXD 316
EKA 183A Programming key 084B8582
superheat controller
(with terminals)
084B8042
Dimensions [mm]
Battery backup
Max. distance between
controller and valve
If battery backup is used, the requirements for
the battery are: 18-24 V DC.
30 m
Accessories
Pressure transducer Temperature sensor
AKS 32R, NSK AKS 21, AKS 11
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Data sheet | Superheat controller type EXD 316
Connections
Necessary connections
Terminals:
1-2
3-4 Battery (the voltage will close the ETS valve if the
5-8 Supply to stepper motor
9-13
Supply voltage 24 V AC / DC
controller losses its supply voltage).
The battery voltage must not be connected from terminals 1
and 2.
Operation via data communication from a MCX
controller.
For manual for data communication, please see the
reference list on last page.
A dedicated transformer must be used.
R = 120 Ω
R
Data communication
20-21 Switch function for start/stop of regulation.
Note:
If a switch is not connected, terminals 20 and 21 must be short
circuited.
Application-dependent connections
Superheat control
14-15 Pt 1000 sensor at evaporator outlet (S2)
15-16 Pt 1000 sensor for measuring air temperature (S4)
17-19 Pressure transmitter type AKS 32R
Note:
The signal can not be shared with other controllers
Control of the valves opening degree with analog signal
21-22 Current signal or voltage signal from other regulation
(Ext. Ref.)
24-26 Alarm relay
There is connection between 24 and 26 in alarm
situations. When the controller is o there is connection
between 24 and 25.
Warning
Any external connection with grounding could create a ground
loop through a diode in the rectier bridge which could destroy
the power supply in EXD 316.
1,2 3,4 21,22
Class II
CANH
CANBUS
ETS / KVS / CCMT2 - CCMT42
/ CCM / CTR
White 5
Black 6
Red 7
Green 8
Connections EXD 316
GND
CANL
Connections EXD 316 /
ETS 6 / CCMT 0 - CCMT 1
Orange 5
Yellow 6
Red 7
Black 8
CANbus transmission lines should be terminated in both ends
with a resistor of approximately 120 Ohms.
Connection to earth will destroy the controller
AC / DC
© Danfoss | DCS (sw) | 2017.01
EXD 316
Danfoss
84N387.10
DKRCC.PD.RT0.A1.02 | 5
OD
Data sheet | Superheat controller type EXD 316
Conguration
Independent superheat regulation
The superheat in the evaporator is controlled by one pressure
transmitter P and one temperature sensor S2. This can be done
setting o61 = 2.
Fitting the “S4” temperature sensor is optional, but the regulation
is improved by an “inner loop control” when the sensor is tted.
EXD 316
Function Parameter Value
Application Mode – superheat regulation o61 2
Selection of normal control mode 056 1
Valve driver (Via Analog Signal)
This is where the controller receives signals from another
controller, after which it controls the valve’s opening degree.
The signal can either be a current signal or a voltage signal.
Details can be found on the section “valve overview”.
I/V
EXD 316
Danfoss
84N394.10
I/V
EXD 316
Danfoss
84B2707.10
I/V
Danfoss
84N393.10
EXD 316
Function Parameter Value
Application Mode – superheat regulation o61 2
Selection of inner loop control mode 056 2
We recommend this inner loop control application mode setting, if
the superheating is to be regulated with precision. Here the S4 and
T0 temperature are part of an inner loop control.
The regulation algorithms require that a temperature sensor be
tted in the chilled medium.
The temperature sensor is connected to input "S4" and mounted
in the chilled medium after the evaporator. (Danfoss calls a sensor
S4 when it is mounted in the refrigerant after the evaporator).
External start/stop of regulation
The controller can be started and stopped externally via a contact
function connected to input terminals 20 and 21. Regulation is
stopped when the connection is interrupted. The function must
be used when the compressor is stopped. The controller then
closes the ETS valve so that the evaporator is not charged with
refrigerant.
Parameter Value Function
o61 1 Application Mode - control via analog signal
Relays
The relay for the alarm function is an alternating relay.
In the event of an alarm the relay will close to connect terminals 24
and 26. This can, for instance, be used for an alarm buzzer. When
there is no alarm or the controller is o, terminals 24 and 25 are
connected.
Parallel Evaporators with common suction line
Since the introduction of EEV, it has been observed the
phenomena the so-called Sleeping Evaporators phenomena have
been observed. This happens when the outlet of the evaporators
has a common suction line.
This is seen when using the Adaptive superheat Mode in some of
the controllers. What happens is that by controlling using the same
superheat reference in both controllers, evaporator No. 1 might be
controlling in the correct manner, but the EEV for evaporator No. 2
might be closed.
However, the measured superheat of controller No. 2 will be the
same as No. 1 because both S2 sensors will measure the same
temperature.
In other words, the open degree of the EEV integrates down to 0%
but, the measured superheat complies with the reference valve.
One solution is to use the Load-dened superheat Mode in the
controller because the measured superheat governs the opening
degree of the connected EEV.
EXD 316
Battery
For safety reasons the liquid ow to the evaporator must be cut
o if there is a power failure to the controller. As the ETS valve
is provided with a stepper motor, it will remain open in such a
situation. When mounting the battery backup, the valve will close
in the event of a power cut.
© Danfoss | DCS (sw) | 2017.01
EXD 316
Danfoss
84N391.10
DKRCC.PD.RT0.A1.02 | 6
84N390.10
EXD 316
EXD 316
84N389.10
Data sheet | Superheat controller type EXD 316
Installation
The EXD 316 is normally mounted on a DIN rail, and the necessary
connections are shown in the diagram. If the sensor S4 is not
used to measure air temperature in connection with thermostat
function or as part of the controlling loop, then it is not necessary
to connect the S4 sensor. The 18-24 V battery input at terminals 15
and 16 is not required if battery back-up is not needed.
Power supply considerations
The terminals 1 and 2 for the voltage supply are not isolated
from the rest of the controller terminals. This means care should
be taken when connecting two or more controllers to the same
voltage supply. In the example below, the two controllers are
connected to the same voltage supply and on the input side,
terminals 21 (Analogue Input) are connected to each controller
and similarly terminals 22 (GND).
This way of connecting the controllers can cause damage and
should be avoided.
Note:
The same applies to other signal inputs e.g. terminals 2 and 4.
See warning page 5.
Danfoss
EXD 316
Stepper motor output
After installation the following checks can be made to the
connection between the EXD 316 controller and the stepper
motor of the valve.
With the power o, check that resistance between terminals 5 and
6 and terminals 7 and 8 is approximately:
ETS 6 / CCMT 0 : 46 Ohm
CCMT 1 : 31 Ohm
ETS / KVS / CCMT 2 - CCMT 8 / CCM / CTR : 53 Ohm
CCMT 16 - CCMT 42: 29 Ohm
Make slight allowances for cable resistance.
If resistance values dier from above, ensure that the cable is
properly connected to the actuator of the stepper motor valve.
1. With the power on and parameter o18 set to 1, measure the
phase current from terminal 5 (or 6) and terminal 7 (or 8 ) with
a true RMS multimeter when the valve is operating. The valve
can be driven from 0% to 100% and vice versa by changing
the valve opening percentage in parameter o45. The phase
current should be 100 mA rms (for ETS) when operating.
2. If this not the case and the cable connections are correct, then
the stepper motor driver in the EXD 316 might be damaged.
Remember to set o18 back to 0 after checks. If checks 1) and
2) are not correct, ensure that motor cable corrections are
correct and the cable length is less than 30 meters.
Output relay contact
The contact of the alarm relay will be made when there is an alarm.
Battery back-up
A battery back-up can be connected to terminals 3 (+) and 4 (-).
It is recommended to use 24 V DC 100 mAh UPS. The voltage
should be at least 18 V and this can be achieved by using two 9 V
100 mAh batteries in series, if temporary solution is to be used.
EXD 316
Data communication
EXD316 can be operated in connection with MCX controllers.
An MCX application software library and several complete
application software packages are available for managing the
valve controller.
Danfoss
In standalone applications EXD316 can be congured by running
an application software on MMIMYK that transfers the setup data.
For EXD conguration manual, please see the reference list on last
page.
© Danfoss | DCS (sw) | 2017.01
DKRCC.PD.RT0.A1.02 | 7
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