Nortec Modbus User Manual

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2560599-D| 05 JUN 2014

Modbus

Installation and
Operation Manual

Using Modbus with Nortec
Humidifiers. Includes installation,
operation maintenance and
troubleshooting information.

Nortec Humidity Ltd.

Nortec Humidity Ltd

Nortec Humidity Ltd

Thank you for choosing Nortec.

INSTALLATION DATE (MM/DD/YYYY)

MODEL #

SERIAL #

CYLINDER #

Proprietary Notice

This document and the information disclosed herein are proprietary data of
document nor the information contained herein shall be reproduced, used, or disclosed to others without the
written authorization of
recipient’s equipment.

., except to the extent required for installation or maintenance of

Neither this

Liability Notice

Nortec does not accept any liability for installations of humidity equipment installed by unqualified personnel or
the use of parts/components/equipment that are not authorized or approved by Nortec.

Copyright Notice

Copyright 2014,

. All rights reserved.

Contents

2 Introduction

2 Requirements

2 Wiring Connections
10 Addressing and

Communication

10 NH-EL

15 NHTC

21 GSTC

25 SETC

29 MHTC

33 MES2 and RH2

39 NHRS

42 Troubleshooting

CAUTION: Servicing

CAUTION: Electrical

CAUTION: Installation

• Disconnect main power before any servicing.

• The plumbing and electrical compartments contain high voltage components and

wiring. Access should be limited to authorized personnel only.

• During and following operation of the humidifier, the steam and components in
contact with the steam such as the blower pack, steam lines, steam distributors,
and condensate lines can become hot and can burn if touched.

• Nortec Humidity Ltd does not accept any liability for installations of humidity
equipment installed by unqualified personnel or the use of
parts/components/equipment that are not authorized or approved by Nortec
Humidity Ltd.

• All electrical work should be done according to local and national electrical code.

• Electrical connection to be performed by a licensed electrician.

• Do not mount on hot surfaces.

• Do not mount in area where freezing can occur.

• Do not mount on vibrating surface.

• Do not mount on floor.

• Regardless of selecting on/off or modulating control method, Nortec humidifiers

must have a closed circuit across its on/off security loop control terminal to
operate. Nortec highly recommends the use of a duct high limit humidistat.

Modbus Installation | 1

Part

Number

Required adapter board and terminals for Modbus
connections.

Required TTL converter for NHRS Modbus
connections.

Introduction

Many Nortec humidifiers feature control boards that include Modbus RTU and can connect to
Modbus networks right out of the box. This document describes how to connect these
humidifiers to such a network and defines the parameters that may be monitored.
Please note that there are differences between Modbus RTU and Modbus TCP. Nortec
humidifiers are Modbus RTU capable and require a gateway (by others) for Modbus TCP
networks. Contact the factory for more information on Modbus TCP communications.

Requirements

NH-EL Humidifiers are capable of Modbus RTU and require no additional hardware for this
connection.

Nortec humidifiers that feature that Total Controller (“TC”) control boards are also capable of
Modbus RTU. These include the NHTC, the GSTC, SETC, and MHTC humidifiers.

Additionally, the RH2 and MES-2 models feature a digital control board that supports Modbus,
however these models require an adapter board to provide the Modbus interface. Finally, the
NHRS also supports Modbus communications; however a TTL converter is required for this
functionality. Refer to following table for more information, items described as “optional” are
for convenience (but not required for Modbus), while items listed as required are needed for
Modbus functionality:

Table 1: Modbus Accessories

Kit Name Kit Description

2553787 NHTC, GSTC, SETC Modbus Connection Optional adapter cable for NHTC, GSTC, SETC.

2560630 MHTC Modbus Interface Optional terminal block for MHTC Modbus interface.

2531585 Modbus Option for OEM Digital Board

2560631 NHRS Modbus converter

Please consult your local Nortec representative to orders connection kits.

Wiring Connections

Using the correct wiring between the humidifier and the Modbus network is important to ensure
reliable communications and reduce the impact of electrical interference. The recommended
wire type is 18 -24 AWG, shielded twisted pair wire with 120 Ohm characteristic impedance. As
an alternative, CAT-5 (“Ethernet”) cable exceeds these specifications and may be used. In this
case, only two of the conductors and the wire shield will be used; care must be taken to isolate
any unused conductors.

Regardless of which wire type is used ensuring the correct shield terminations is necessary to
prevent electrical interference. The wire shield should be terminated at either the humidifier or
the Modbus system, but not both. This allows induced current to “drain”; if the shield is
terminated at both ends it will function as a conductor and can actually increase electrical
interference. To minimize signal loss a wire run should not exceed 2000 feet. Additionally, to
ensure communication reliability, it is recommended that no more than 8 humidifiers are

2 |Modbus Installation

connected to a single chain/bus. The humidifiers should be the same type but do not need to
be the same capacity. For example it is not recommended to have an NHTC and a GSTC as part
of the same chain, but it is acceptable to have an NHTC-200 and an NHTC-30 as part of the
same chain. Connecting additional non-Nortec equipment into a Modbus chain is possible;
however it is important to ensure that all devices are operating with identical baud rate, parity,
and stop bits, and that each device has a unique Modbus address.

Figure 1: Example Daisy Chain Diagram for NH-EL, NHTC, GS, SE

Modbus Installation | 3

NH-EL Models

The NH-EL models use a 3 pole connector on the main processor card for Modbus connection.
This 3 pole connector is provided with all NH-EL and connections can be made directly to this
plug. Refer to Figure 2 and Figure 3 for connection location and wiring.

Please note: there is a 120 Ohm termination resistor available on board. When the jumper J4
is on, 120 Ohm is enabled. When the jumper J4 is off, 120 Ohm is disabled.

4 |Modbus Installation

Figure 2: NHEL Modbus 3 Pole Plug Location

Note

NHTC, GSTC, SETC, and MHTC Models

The NHTC, GSTC, SETC, and MHTC models use a multifunction RJ45 plug on the mainboard to
provide Modbus communications. Connections can be made directly to this plug or,
alternatively, using one of accessories listed above.

Refer to figure 4 for information on the wiring connections for these units.

: This instruction manual covers the connections and points for the GSTC B+ and SETC B+
models only. Older models, manufactured pre-2009 do not include the RJ45 plug and require
an additional interface cable. Contact Nortec for information on connecting these units.

MES2 and RH2 Models

The MES2 and RH2 models require a Modbus support board to provide a connection point. This
board can be factory installed if indicated at time of order, or retrofit to existing units in the field.

Refer to Figure 5 for information on the wiring connections for these units.

NHRS Models

The NHRS models require a Modbus kit to translate information from the processor board into
Modbus RTU information. This kit can be factory installed if specified at time of order or retrofit
to existing units in the field. Refer to figure 6 for information on the wiring connections for these
units.

Modbus Installation | 5

6 |Modbus Installation

Figure 3: NH-EL Modbus Wiring Diagram

Figure 4: TC Modbus Wiring Diagram

Modbus Installation | 7

8 |Modbus Installation

Figure 5: MES2 and RH2 Modbus Wiring Diagram

Figure 6: NHRS Modbus Wiring Diagram

Modbus Installation | 9

Modbus Communication Set-up

1
2

3
4
5

Note: By default, Modbus is disabled. To enable Modbus, select

Modbus

under

Modbus

Parameters

. Select ON and confirm the selection by pressing the

Check Mark

button.

6

7

Addressing and Communications

Once the humidifier has been wired to the network, control variables must be mapped to allow
for control of the humidifier. The specific variables and communications requirements for each
humidifier are described in the following sections.

NH-EL Electrode Steam Humidifiers

After wiring connections have been completed, the humidifier needs to be setup to operate and
communicate either through the Modbus or BACnet interface.

The default Modbus address for an NH-EL is 10. If multiple units were included on an order, the
addresses of individual units may vary. To view or change the Modbus address:

Press the Menu icon on the lower left corner of the screen, to access the menu.
When prompted for a password, enter 0335 using the number pad. Press the Check Mark

icon to confirm.

Select the Configuration menu.
Select the Comms. menu.
Using the navigation buttons on the top right of the screen, scroll down to the Modbus

Parameters.

Select the Modbus Address setting. Using the Up and Down arrows, select a value between

1 and 247 inclusive as desired and press the Check Mark button to confirm the selection. It
is recommended to leave the parity and baud rate settings to their factory defaults (Even
and 9600 respectively) unless communication problems occur.

Press Back repeatedly until you return to the home screen.

This procedure is summarized below:

Main Menu > 0335 > Configuration > Comms. Menu > Modbus Parameters >

Addr: 10 (1 – 247 acceptable)
Parity: Even (None, Even, Odd)
Baud Rate: 9600 (9600, 19200, 38400, 115200)

10 |Modbus Installation

Control Signal Setting

1
2

3
4

Note: Refer to the CONTROL SETTING section of the NH Series Installation and Operation
Manual for more information on the above settings.

5

Modbus Parameters

By default the humidifier is configured operate on a hardwired control signal supplied through
the unit terminal strip. This can be changed to allow the humidifier to function entirely through
its Modbus or BACnet interface.

To adjust this setting:

Press the Menu icon on the lower left corner of the screen, to access the menu.
When prompted for a password, enter 0335 using the number pad. Press the Check Mark

icon to confirm.

Select the Configuration menu.
Select the Control Settings menu. The following settings can be adjusted:

Source

Control Mode

Control Channels

Analog: Use hardwired control signal
Modbus: Write control signal through Modbus interface

Demand: Use a demand control signal
RH P: Use a sensor value and proportional
RH PI: Use a sensor value and proportional-integral control band

Single: Use a signal channel control signal
Dual: Use a dual channel control signal

Press Check Mark to confirm choice and then Back repeatedly to return to the home screen

when complete.

This procedure is summarized below:

Main Menu > 0335 > Configuration > Control Settings >

Source: Analog, Modbus,
Control Mode: Demand, RH P, or RH PI
Control Channels: Single or Dual

The NH-EL uses the following parameters for Modbus communication:

Signaling Type EIA-485

Transmission Mode RTU

Baud Rate 9600

Data Bits 8

Stop Bits 1

Parity Even

Address / Unit Number 10*

*Default, may vary for multi-unit orders.

It is important to note that the signaling type, transmission mode, data bits and stop bits cannot
be modified. Parity, baud rate and unit address can be modified as required.

Modbus Installation | 11

Parameter

Name

Description

Modbus

Addr.

Type

Format

Range

Unit

R/W

Details

Write RH or

cylinder A

Requires Modbus or

primary control signal

Requires Modbus or

operation mode

Requires Modbus or

enabled

Requires Modbus or

operation mode

Limits output to

only)

Limits output to

only)

BMS timeout

BACnet

It is recommend to not

the factory default (300)

Remotely disable

for the unit

Writes the

for cylinder A

Use only when sending

primary space setpoint

Writes the

for cylinder A

The following points may be mapped for control:

Dinput_A1

Dinput_A2

Dinput_B1

Dinput_B2

Manual_
Capcity_A

Demand signal
value to control
channel 1 for

Write RH or
Demand signal
value to control
channel 2 for
cylinder A

Write RH or
Demand signal
value to control
channel 1 for
cylinder B

Write RH or
Demand signal
value to control
channel 2 for
cylinder B

Sets a manual
capacity limit
restriction for
cylinder A

40005

40006

40010

40011

40002

Holding

Register

Holding

Register

Holding

Register

Holding

Register

Holding

Register

Integer 0 - 100 % Write

Integer 0 - 100 % Write

Integer 0 - 100 % Write

Integer 0 - 100 % Write

Integer 0 - 100 % Write

BACnet to be enabled.
For most common
configurations, this is the

BACnet to be enabled.
Only applies to NH-EL­150 and NH-EL-200 with
cylinders in independent

BACnet to be enabled.
Only applies to NH-EL­150 and NH-EL-200 with
dual channel control

BACnet to be enabled.
Only applies to NH-EL­150 and NH-EL-200 with
cylinders dual channel
control enabled and
cylinders in independent

percentage of total
cylinder capacity for
cylinder A (NH-EL-150
and NH-EL-200 models

Manual_
Capcity_B

BMS_
Timeout

Remote_
Disable

SP_Chan_A
1

SP_Chan_A
2

Sets a manual
capacity limit
restriction for
cylinder B (if
present)

for Modbus and

steam production

desired space
setpoint for
control channel 1

desired space
setpoint for
control channel 2

40007

40013

40001

40003

40004

Holding

Register

Holding

Register

Holding

Register

Holding

Register

Holding

Register

Integer 0 - 100 % Write

Integer 0 - 300 s Write

Integer 0 or 1 - Write

Integer 0 - 95 % Write

Integer 10 - 95 % Write

percentage of total
cylinder capacity for
cylinder B (NH-EL-150
and NH-EL-200 models

change the value from

0 = Idle/Humidify
1 = Disable

RH values to Dinput_A1.
For most common
configurations this is the

Use only when sending
RH value to Dinput_A2
with dual channel control
enabled

12 |Modbus Installation

Use only with NH-EL-

mode

Use only with NH-EL-

mode

0 = Analog

4 = LonWorks

1 = Demand

3 = RH PI

Selects method

channels

Displays channel 1

capacity for cylinder A

Displays channel 2

capacity for cylinder A

Displays channel 1

200 models only)

Displays channel 2

200 models only)

Reads the status

A

Reads the status

B

SP_Chan_B
1

SP_Chan_B
2

Signal_
Source

Control_
Mode

Control_
Channel

Writes the
desired space
setpoint for
control channel 1
for cylinder B

Writes the
desired space
setpoint for
control channel 2
for cylinder B

Selects signal
source to control
unit

Selects method
to control unit

to control

40008

40009

40014

40015

40016

Holding

Register

Holding

Register

Holding

Register

Holding

Register

Holding

Register

Integer 0 - 95 % Write

Integer 10 - 95 % Write

Integer 0 - 4 - Write

Integer 1 - 3 - Write

Integer 0 - 1 - Write

150 and NH-EL-200
models when sending
RH value to Dinput_B1
and cylinders are in
independent operation

150 and NH-EL-200
models when sending
RH value to Dinput_B2
with dual channel
control enabled and
cylinders are in
independent operation

1 = Modbus
2 = BACnet/IP
3 = BACnet/MS

2 = RH P

0 = Single Channel
1 = Dual Channel

Input_A1

Input_A2

Input_B1

Input_B2

Blower_
Pack_A

Blower_
Pack_B

Displays channel
1 demand for
cylinder A

Displays channel
2 demand for
cylinder A

Displays channel
1 demand for
cylinder B

Displays channel
2 demand for
cylinder B

of the blower
pack for cylinder

of the blower
pack for cylinder

30004

30005

30014

30015

30008

30018

Input

Register

Input

Register

Input

Register

Input

Register

Input

Register

Input

Register

Integer 0 - 100 % Read

Integer 0 - 100 % Read

Integer 0 - 100 % Read

Integer 0 - 100 % Read

Integer 0 or 1 - Read

Integer 0 or 1 - Read

demand/sensed RH as
a percentage of cylinder

demand/sensed RH as
a percentage of cylinder

demand/sensed RH as
a percentage of cylinder
capacity for cylinder B
(NH-EL-150 and NH-EL-

demand/sensed RH as
a percentage of cylinder
capacity for cylinder B
(NH-EL-150 and NH-EL-

0 = Open
1 = Closed

0 = Open
1 = Closed

Fan_
Activate_A

Indicates if air
handle or
furnace is
activated for
cylinder A

30009

Input

Register

Integer 0 or 1 - Read

Modbus Installation | 13

0 = Not Activated
1 = Activated