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

Indicates if air

cylinder B

Reads the status

unit

Reads the status

request on the unit

0 = No Service

1 = Service Required

0 = Humidifying

9 = Fault

0 = Humidifying

9 = Fault

Demand Mode:

PID calculation

Demand Mode:

PID calculation

Reads the status

for cylinder A

Reads the status

for cylinder B

Displays the total time

running since last reset

Displays the total time

running since last reset

Reads the

cylinder A

An equated run time

System_Demand_A

Reads the

cylinder B

An equated run time

System_Demand_A

Fan_
Activate_B

Do_Fault_
A

Do_
Service_A

Humidifier
_Status_A

Humidifier
_Status_B

handle or furnace
is activated for

of a fault on the

of a service

Reads the status
of the unit for
cylinder A

Reads the status
of the unit for
cylinder A

30019

30025

30024

30003

30026

Input

Register

Input

Register

Input

Register

Input

Register

Input

Register

Integer 0 or 1 - Read

Integer 0 or 1 - Read

Integer 0 or 1 - Read

Integer 0 - 9 - Read

Integer 0 - 9 - Read

0 = Not Activated
1 = Activated

0 = No Fault
1 = Fault

Required

1 = Idle
2 = Idle Drain
3 = Keepwarm
4 = Filling
5 = Draining
6 = Disabled
7 = Safety Loop
8 = Warning

1 = Idle
2 = Idle Drain
3 = Keepwarm
4 = Filling
5 = Draining
6 = Disabled
7 = Safety Loop
8 = Warning

System_
Demand_A

System_
Demand_
B

Safety_
Loop_A

Safety_
Loop_B

Run_Time
_A

Run_Time
_B

Weighted_
Hours_A

Weighted_
Hours_B

Reads the demand
for cylinder A

Reads the demand
for cylinder A

of the safety loop

of the safety loop

Reads operating
time for cylinder A

Reads operating
time for cylinder B

weighted time for

weighted time for

30006

30016

30007

30017

30010

30020

30011

30021

Input

Register

Input

Register

Input

Register

Input

Register

Input

Register

Input

Register

Input

Register

Input

Register

Integer 0 – 100 % Read

Integer 0 – 100 % Read

Integer 0 or 1 - Read

Integer 0 or 1 - Read

Integer 0 - 5000 Hrs Read

Integer 0 - 5000 Hrs Read

Integer 0 - 5000 Hrs Read

Integer 0 - 5000 Hrs Read

Summation of Input_A1
and Input_A2

RH Mode:

Summation of Input_B1
and Input_B2

RH Mode:

0 = Open
1 = Closed

0 = Open
1 = Closed

cylinder A has been

cylinder B has been

based on Run_Time_A x

based on Run_Time_A x

14 |Modbus Installation

Modbus Address

1
2
3
4
5

Note: Do NOT modify other settings in the Factory settings manual. Adjusting other settings
can cause serious damage to the humidifier.

6

7

NHTC Electrode Steam Humidifiers

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

The default Modbus address for an NHTC is 1. If multiple units were included on an order, the
addresses of individual units may vary. To view or change the unit number:

Press the Menu key to access the menu.
When prompted for a password, enter 0459 using the arrow keys. Press Set to confirm.
Select the Factory Settings menu and press the Set key.
Select the Core Parameters menu and press the Set key.
Select the Modbus Parameters menu and press the Set key.

Select the Address setting and press Set to modify. Enter a value between 1 and 127

inclusive as desired and press Set to confirm the solution. It is recommended to leave the
parity and timeout settings to their factory defaults (Even and 300 respectively) unless
communication problems occur.

Press Esc repeatedly until you return to the home screen.

This procedure is summarized below:

Menu > 0459 > Factory Settings > Core Parameters > Modbus Parameters >

Parity: Even
Addr: 1 (Default, 1 – 127 acceptable)
Timeout: 300 seconds (Default, 5 – 600 acceptable)

Modbus Installation | 15

Control Signal Setting

1
2

3

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

4

By default the humidifier operation is configured 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 interface.

To adjust this setting:

Press the Menu key to access the menu.
When prompted for a password, enter 0335 using the arrow keys. Confirm the password

with set.

Select the Control Settings menu and press the Set key. The following settings can be

adjusted:

Source

REG Mode

MOD Mode

CNT Type Setting not relevant when writing control signal through Modbus.

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

Demand: Use a demand control signal
RHp: Use a sensor value and proportional
RHpi: Use a sensor value and proportional-integral control band

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

Press Esc repeatedly to return to the home screen when complete.

This procedure is summarized below:

Menu > 0335 > Control Settings >

Source: Analog or Digital
Reg Mode: Demand, RHp, or RHpi
Mod Mode: Single CH or Dual CH
CNT Type: As required

16 |Modbus Installation

Modbus Parameters

Address / Unit Number

1*

The NHTC uses the following parameters for communication:

Signaling Type EIA-485

Transmission Mode RTU

Baud Rate 9600

Data Bits 8

Stop Bits 1

Parity Even

*Default, may vary for multi-unit orders.

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

Modbus Installation | 17

Variable Name

Description

Addr.

Type

Format

Range

Uni

t

R/W

Details

Sets a

cylinder 1.

Sets a

present).

Write RH or

cylinder 1

Write RH or

cylinder 2

Requires network controls

mode

Write RH or

cylinder 1

Requires network controls

mode

Writes the

cylinder 1

Writes the

cylinder 2

Use only with NHTC-150

mode

Writes the

cylinder 1

The following points may be mapped for control:

CapLimitCyl1

CapLimitCyl2

RHDemCyl1

RHDemCyl2

RHDem2Cyl1

manual
capacity
restriction for

manual
capacity
restriction for
cylinder 2 (if

Demand
signal value
to control
channel 1 for

Demand
signal value
to control
channel 1 for

Demand
signal value
to control
channel 2 for

40026

41026

40264

41264

40265

Holding

Register

Holding

Register

Holding

Register

Holding

Register

Holding

Register

Integer

Integer

Integer 0 - 100 % Write

Integer 0 - 100 % Write

Integer 0 - 100 % Write

50-

100

50-

100

% Write

% Write

Limits output to
percentage of total
cylinder capacity

Limits output to
percentage of total
cylinder capacity for
cylinder 2 (NHTC-150 and
NHTC-200 models only)

Requires network controls
(NetSensor = 1), for most
common configurations
this is the primary control
signal

(NetSensor = 1), only
applies to NHTC-150 and
NHTC-200 with cylinders
in independent operation

Requires network controls
(NetSensor = 1), only
applies to NHTC-150 and
NHTC-200 with dual
channel control enabled

RHDem2Cyl2

Set1Cyl1

Set1Cyl2

Set2Cyl1

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

desired space
setpoint for
control
channel 1 for

desired space
setpoint for
control
channel 1 for

desired space
setpoint for
control
channel 2 for

41265

40024

41024

40010

Holding

Register

Holding

Register

Holding

Register

Holding

Register

Integer 0 - 100 % Write

Integer 30-95 % Write

Integer 30-95 % Write

Integer 30-95 % Write

(NetSensor = 1), only
applies to NHTC-150 and
NHTC-200 with cylinders
dual channel control
enabled and cylinders in
independent operation

Use only when sending RH
value to RHDem1, for
most common
configurations this is the
primary space setpoint

and NHTC-200 models
when sending RH value to
RHDem1 and cylinders are
in independent operation

Use only when sending RH
value to RHDem2 with
dual channel control
enabled

18 |Modbus Installation

Use only with NHTC-150

mode

Remotely

cylinder 1

Used only for NHTC-150

255 = Disabled

Switches

control signal

Displays

cylinder 1

Displays channel 1

cylinder 1

Displays channel 1

200 models only)

Displays

cylinder 1

Displays channel 2

cylinder 1

Displays channel 2

200 models only)

Reads fault
status

Input

Register

0 or
255

0 = No Fault
255 = Fault Warning

Reads service

status

0 = Idle / Standby

Humidifying

Reads operating time for

hours = (Value x 5)/60

Writes the
desired space

Set2Cyl2

DisableCyl1

DisableCyl2

NetSensor

setpoint for
control
channel 2 for
cylinder 2

disable steam
production for

Remotely
disable steam
production for
cylinder 2

between hard
wired or
network

41010

40262

41262

40226

Holding

Register

Holding

Register

Holding

Register

Holding

Register

Integer 30-95 % Write

Integer

Integer

Integer 0 or 1 - Write

0 or

255

0 or

255

- Write

- Write

and NHTC-200 models
when sending RH value to
RHDem2 with dual
channel control enabled
and cylinders are in
independent operation

0 = Normal operation
255 = Disabled

and NHTC-200 models.
Both cylinder 1 and 2
must be disabled to
completely disable
humidifier.
0 = Normal operation

1= Network sensor or
demand
0 = Wired sensor or wired
demand

Ch1DemCyl1

Ch1DemCyl2

Ch2DemCyl1

Ch2DemCyl2

Fault Warning

Service Warning

channel 1
demand for

Displays
channel 1
demand for
cylinder 2

channel 2
demand for

Displays
channel 2
demand for
cylinder 2

warning

30348

31348

30349

31349

30301

30300

Input

Register

Input

Register

Input

Register

Input

Register

Input

Register

Integer

Integer

Integer

Integer

Integer

Integer

0 -

100

0 -

100

0 -

100

0 -

100

0 or

255

% Read

% Read

% Read

% Read

- Read

- Read

demand as a percentage
of cylinder capacity for

demand / output as a
percentage of cylinder
capacity for cylinder 2
(NHTC-150 and NHTC-

demand as a percentage
of cylinder capacity for

demand / output as a
percentage of cylinder
capacity for cylinder 2
(NHTC-150 and NHTC-

0 = No Service Warning
255 = Service Warning

Unit Status

Cyl1OpTime

Reads unit
status

Reads
operating
time for
cylinder 1

30312

30213

Input

Register

Input

Register

Integer

Integer

0 or

255

0 -

65535 5 min

- Read

255 = Active /

cylinder 1. Each number

Read

Modbus Installation | 19

is equivalent to 5 minutes
of operation. Time in

Reads operating time

5)/60

11 = Security loop open

run for 72hrs

Unit will not run until

fault

Displays the

cylinders)

Cyl2OpTime

UnitStatus

Reads
operating
time for
cylinder 2

Displays
status
warnings

31213

31385

Input

Register

Input

Register

0 -

Integer

Integer 0-99 - Read

6553

5

5

min

Read

for cylinder 2 (NHTC­150 and NHTC-200
only). Each number is
equivalent to 5 minutes
of operation.
Time in hours = (Value x

19 = Cylinder spent
warning
If status 19, unit will
have yellow service light
on and will continue to

CylSpent

SysTotalDem

Displays
cylinder end
of life fault

total demand
on system
(sum both

30378

30251

Input

Register

Input

Register

Integer 0-99 - Read

Integer

0 -

100

% Read

cylinder is replaced
19 = Cylinder spend

Sum of Steam Output
Cyl-1 and Cyl-2 in
percentage

20 |Modbus Installation

Modbus Address

1
2
3
4
5

6

Control Signal Setting

GSTC Gas Fired Steam Humidifiers

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

The default Modbus address for a GSTC is 1. If multiple units were included on an order, the
addresses of individual units may vary.

To view or change the unit number:

Press the Menu key to access the menu.
When prompted for a password, enter 0335 using the arrow keys. Press Set to confirm.
Select the Control Settings menu and press the Set key.
Select the Modbus Parameters menu and press the Set key.
Select the Address setting and press Set to modify. Enter a value between 1 and 127

inclusive as desired and press Set to confirm the solution. It is recommended to leave the
parity and timeout settings to their factory defaults (None1 and 300 respectively) unless
communication problems occur.

Press Esc repeatedly until you return to the home screen.

This procedure is summarized below:

Menu > 0335 > Control Settings > Modbus Parameters >

Parity: None1
Addr: 1 (Default, 1 – 127 acceptable)
Timeout: 300 seconds (Default, 5 – 600 acceptable)

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 interface.

Modbus Installation | 21

1
2

3

Note: Refer to the

GSTC Total Controller Flow Chart

section of the GS Series Installation and

Operation Manual for more information on the above settings.

4

Modbus Parameters

Signaling Type

EIA-485

Transmission Mode

RTU

Baud Rate

9600

Data Bits

8

Stop Bits

1

Parity

None

Address / Unit Number

1*

To adjust this setting:

Press the Menu key to access the menu.
When prompted for a password, enter 0335 using the arrow keys. Confirm the password

with set.

Select the Control Settings menu and press the Set key. The following settings can be

adjusted:

Source:

REG Mode:

MOD Mode:

CNT Type: Setting not relevant when writing control signal through modbus.

Analog: Use hardwired control signal
Digital: Write control signal through modbus interface

Demand: Use a demand control signal
RHp: Use a sensor value and proportional
RHpi: Use a sensor value and proportional-integral control band

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

Press Esc repeatedly to return to the home screen when complete.

This procedure is summarized below:

Menu > 0335 > Control Settings >

Source: Analog or Digital
Reg Mode: Demand, RHp, or RHpi
Mod Mode: Single CH or Dual CH
CNT Type: As required

The GSTC uses the following parameters for communication:

*Default, may vary for multi-unit orders.

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

22 |Modbus Installation

Variable

Name

Description

Addr

Type

Format

Range

Unit

R/W

Additional Details

Write RH or

channel 1

Write RH or

channel 2

Writes the

control channel 1

Writes the

control channel 2

Remotely

humidifier

0 = Demand Signal

Integral Control)

0 = Hard wired

value

Read RH or

1

Read RH or

2

Read space

control channel 1

Read space

control channel 2

Confirms remote
disable status

Input

Register

0 = Run
255 = Disable

The following points may be mapped for control:

RHDem1

RhDem2

Set1

Set2

Disable

InputType

Demand signal
value to control

Demand signal
value to control

desired space
setpoint for

desired space
setpoint for

disables the

Selects the
control type that
the humidifier
operates on

40264

40265

40024

40025

40262

40007

Holding

Register

Holding

Register

Holding

Register

Holding

Register

Holding

Register

Holding

Register

Analog 0-100 % Write

Analog 0-100 % Write

Analog 30-95 % Write

Analog 30-95 % Write

Analog 0, 255 - Write

Analog

0,1,2,3

,

- Write

Requires network
controls
(NetSensor = 1)

Requires network
controls
(NetSensor = 1)

Use only when
sending RH value
to RHDem1

Use only when
sending RH value
to RHDem2

0 = Run
255 = Disable

1 = On/Off Signal
2 = RH Sensor
Value (Use
Proportional
Control)
3 = RH Sensor
Value (Use
Proportional-

NetSensor

RHDem1

RHDem2

Set1

Set2

Disable

Switches
between hard
wired or network
control signal

Demand signal
value from
control Channel

Demand signal
value from
control Channel

setpoint for

setpoint for

40226

30348

30349

40024

40025

30989

Holding

Register

Input

Register

Input

Register

Input

Register

Input

Register

Binary 0,1 - Write

Analog 0-100 % Read

Analog 0-100 % Read

Analog 30-95 % Read

Analog 30-95 % Read

Analog 0, 255 - Read

control signal
1 = Use Modbus to
write control signal

Displays signal
value as a
percentage

Displays signal
value as a
percentage

Only available for
InputType 2 or 3

Only available for
InputType 2 or 3

Modbus Installation | 23

0 = Demand Signal

Integral Control)

0 = Hard wired

value

Read fault
status

Input

Register

0 = No Fault
1 = Fault Detected

0 = No Service

Required

Read

status

0 = Idle / Standby

Humidifying

0 = Communication

Communication

Read

hours of unit

Read

at humidifier)

Read 3 day

at humidifier)

SysDemand

Read system

demand

Displays output as

capacity

Read hours

service

Displays hours

next service.

Displays the status

1 = Closed

InputType

Confirms the
control type
that the
humidifier
operates on

40007

Input

Register

Analog 0,1,2,3 - Read

1 = On/Off Signal
2 = RH Sensor
Value (Use
Proportional
Control)
3 = RH Sensor
Value (Use
Proportional-

Confirms the

NetSensor

Fault

Service

Status

Connection

HourOpt

KeepWarm

system control
type

Read service
warning status

humidification

Read
connection
status

operational

keepwarm
option status
(enable/disable

40226

30301

30300

30302

40267

30350

30356

Input

Register

Input

Register

Input

Register

Input

Register

Input

Register

Input

Register

Binary 0,1 - Read

Binary 0,1 - Read

Binary 0,1 - Read

Binary 0,1 - Read

Binary 0,1 - Read

Analog

Analog 0,1 - Read

0 -

Infinity

hrs Read

control signal
1 = Use Modbus to
write control signal

Warning
1 = Service

1 = Active /

Error
1 = Normal

Displays hours of
operation.

Bit0 - KEEPWARM
0 = Disabled
1 = Enabled

3DayDrain

ServHours

SecurityLoop

24 |Modbus Installation

drain option
status
(enable/disable

output /

before next

Displays status
of security loop.

30356

30347

30352

30364

Input

Register

Input

Register

Input

Register

Input

Register

Analog 0,1 - Read

Analog 0-100 % Read

Analog 500-0 hrs Read

Analog 0,1 - Read

Bit1 - 3 DAY DRAIN
0 = Disabled
1 = Enabled

percentage of

remaining until

of the security loop
on terminals 1 and

2. Loop must be
"closed" for
humidifier to
operate.
0 = Open

Modbus Address

1
2
3
4
5

6

SETC Steam Exchange Humidifiers

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

The default Modbus address for a SETC is 1. If multiple units were included on an order, the
addresses of individual units may vary.

To view or change the unit number:

Press the Menu key to access the menu.
When prompted for a password, enter 0335 using the arrow keys. Press Set to confirm.
Select the Control Settings menu and press the Set key.
Select the Modbus Parameters menu and press the Set key.
Select the Address setting and press Set to modify. Enter a value between 1 and 127

inclusive as desired and press Set to confirm the solution. It is recommended to leave the
parity and timeout settings to their factory defaults (None1 and 300 respectively) unless
communication problems occur.

Press Esc repeatedly until you return to the home screen.

This procedure is summarized below:

Menu > 0335 > Control Settings > Modbus Parameters >

Parity: None1
Addr: 1 (Default, 1 – 127 acceptable)
Timeout: 300 seconds (Default, 5 – 600 acceptable)

Modbus Installation | 25

Control Signal Setting

1
2

3

Note: Refer to the

SETC Humidifier Configuration

section of the SE Series Installation and

Operation Manual for more information on the above settings.

1

Modbus Parameters

Signaling Type

EIA-485

Transmission Mode

RTU

Baud Rate

9600

Data Bits

8

Stop Bits

1

Parity

None

Address / Unit Number

1*

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 interface.

To adjust this setting:

Press the Menu key to access the menu.
When prompted for a password, enter 0335 using the arrow keys. Confirm the password

with set.

Select the Control Settings menu and press the Set key. The following settings can be

adjusted:

Source

REG Mode

MOD Mode

CNT Type Setting not relevant when writing control signal through Modbus.

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

Demand: Use a demand control signal
RHp: Use a sensor value and proportional
RHpi: Use a sensor value and proportional-integral control band

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

Press Esc repeatedly to return to the home screen when complete.

This procedure is summarized below:

Menu > 0335 > Control Settings >

Source: Analog or Digital
Reg Mode: Demand, RHp, or RHpi
Mod Mode: Single CH or Dual CH
CNT Type: As required

The SETC uses the following parameters for communication:

*Default, may vary for multi-unit orders.

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

26 |Modbus Installation

Variable

Name

Description

Addr

Type

Format

Range

Unit

R/W

Additional Details

Write RH or

channel 1

Write RH or

channel 2

Writes the desired

control channel 1

Writes the desired

control channel 2

Remotely disables
the humidifier

Holding

Register

0 = Run
255 = Disable

0 = Demand Signal

Control)

Switches between

signal

0 = Hard wired control

control signal value

Read RH or

Channel 1

Read RH or

Channel 2

Read space

channel 1

Read space

channel 2

Confirms remote
disable status

Input

Register

0 = Run
255 = Disable

0 = Demand Signal

Control)

The following points may be mapped for control:

RHDem1

RhDem2

Set1

Set2

Disable

InputType

NetSensor

Demand signal
value to control

Demand signal
value to control

space setpoint for

space setpoint for

Selects the control
type that the
humidifier
operates on

hard wired or
network control

40264

40265

40024

40025

40262

40007

40226

Holding

Register

Holding

Register

Holding

Register

Holding

Register

Holding

Register

Holding

Register

Analog 0-100 % Write

Analog 0-100 % Write

Analog 30-95 % Write

Analog 30-95 % Write

Analog 0, 255 - Write

Analog 0,1,2,3 - Write

Binary 0,1 - Write

Requires network controls
(NetSensor = 1)

Requires network controls
(NetSensor = 1)

Use only when sending RH
value to RHDem1

Use only when sending RH
value to RHDem2

1 = On/Off Signal
2 = RH Sensor Value (Use
Proportional Control)
3 = RH Sensor Value (Use
Proportional-Integral

signal
1 = Use Modbus to write

RHDem1

RHDem2

Set1

Set2

Disable

InputType

Demand signal
value from control

Demand signal
value from control

setpoint for control

setpoint for control

Confirms the
control type that
the humidifier
operates on

30348

30349

40024

40025

30989

40007

Input

Register

Input

Register

Input

Register

Input

Register

Input

Register

Analog 0-100 % Read

Analog 0-100 % Read

Analog 30-95 % Read

Analog 30-95 % Read

Analog 0, 255 - Read

Analog 0,1,2,3 - Read

Displays signal value as a
percentage

Displays signal value as a
percentage

Only available for InputType
2 or 3

Only available for InputType
2 or 3

1 = On/Off Signal
2 = RH Sensor Value (Use
Proportional Control)
3 = RH Sensor Value (Use
Proportional-Integral

Modbus Installation | 27

0 = Hard wired control

control signal value

Input

Register

0 = No Fault
1 = Fault Detected

Read service
warning status

Input

Register

0 = No Service Warning
1 = Service Required

Read

status

0 = Communication Error

Communication

Read operational
hours of unit

Input

Register

0 -

Infinity

Displays hours of
operation.

Read keepwarm

humidifier)

Read 3 day drain

humidifier)

SysDemand

Read system
output / demand

Input

Register

Displays output as
percentage of capacity

Read hours before
next service

Input

Register

Displays hours remaining
until next service.

Displays the status of the

1 = Closed

Confirms the

NetSensor

Fault Read fault status 30301

Service

Status

Connection

HourOpt

KeepWarm

3DayDrain

system control
type

humidification

Read connection
status

option status
(enable/disable at

option status
(enable/disable at

40226

30300

30302

40267

30350

30356

30356

Input

Register

Input

Register

Input

Register

Input

Register

Input

Register

Binary 0,1 - Read

Binary 0,1 - Read

Binary 0,1 - Read

Binary 0,1 - Read

Binary 0,1 - Read

Analog

Analog 0,1 - Read

Analog 0,1 - Read

hrs Read

signal
1 = Use Modbus to write

0 = Idle / Standby
1 = Active / Humidifying

1 = Normal

Bit0 - KEEPWARM
0 = Disabled
1 = Enabled

Bit1 - 3 DAY DRAIN
0 = Disabled
1 = Enabled

ServHours

SecurityLoop

Displays status of
security loop.

30347

30352

30364

Input

Register

Analog 0-100 % Read

Analog 500-0 hrs Read

Analog 0,1 - Read

security loop on terminals
1 and 2. Loop must be
"closed" for humidifier to
operate.
0 = Open

28 |Modbus Installation

Modbus Address

1
2
3
4
5
6

7

MHTC Evaporative Media Humidifiers

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

The default Modbus address for a MHTC is 1. If multiple units were included on an order, the
addresses of individual units may vary.

To view or change the unit number:

Press the Menu key to access the menu.
Select the User option and press Set.
When prompted for a password, enter 8808 using the arrow keys. Press Set to confirm.
Select the Settings menu and press the Set key.
Select the Modbus menu and press the Set key.
Select the Address setting and press Set to modify. Enter a value between 1 and 127

inclusive as desired and press Set to confirm the solution. It is recommended to leave the
parity and timeout settings to their factory defaults (None1 and 300 respectively) unless
communication problems occur.

Press Esc repeatedly until you return to the home screen.

This procedure is summarized below:

Menu > User > 8808 > Modbus >

Parity: None1
Addr: 1 (Default, 1 – 127 acceptable)
Timeout: 300 seconds (Default, 5 – 600 acceptable)

Modbus Installation | 29

Control Signal Setting

1
2
3

4

Note: Refer to the

MHTC Humidifier Configuration

section of the MH Series Installation and

Operation Manual for more information on the above settings.

1

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 interface.

To adjust this setting:

Press the Menu key to access the menu.
Select the User options and press Set.
When prompted for a password, enter 8808 using the arrow keys. Confirm the password

with set.

Select the Controls menu and press the Set key. The following settings can be adjusted:

Signal Source

Hum. Control

Control Sign Setting not relevant when writing control signal through Modbus.

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

External: Use a demand control signal
Int(p): Use a sensor value and proportional
int(pi): Use a sensor value and proportional-integral control band

Press Esc repeatedly to return to the home screen when complete.

This procedure is summarized below:

Menu > User > 8808 > Controls >

Signal Source: Analog or Modbus
Hum. Control: External, Int(p), or Int(pi)
Control Sign: As required

30 |Modbus Installation

Modbus Parameters

Signaling Type

EIA-485

Transmission Mode

RTU

Baud Rate

9600 (cannot be changed)

Data Bits

8

Stop Bits

1

Parity

None

Address / Unit Number

1*

Variable
Name

Description

Addr

Type

Format

Range

Unit

R/W

Details

Writes a control

error.

Reads/Writes

setpoint

Used when

0 = Allow normal

humidifier

0 = Demand Signal

method)

The MHTC uses the following parameters for communication:

*Default, may vary for multi-unit orders.

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

The following points may be mapped for control:

CapLimit

RHDem1

Set1

Disable

Manual
Capacity Limit

Reads/writes
a control
signal to the
humidifier

the desired
space

Remotely
disables
humidifier

40008

40053

40005

40052

Holding

Register

Holding

Register

Holding

Register

Holding

Register

Integer

Integer

Integer

Integer 0 or 1 - Write

30 ­100

0 -

100

10 -

90

% Write Limits unit output.

% Write

% Write

signal to the
humidifier. This input
only works if
humidifier is set to
network control
NetSensor set to 1)
in the control
settings. If the
system is set to
network control no
signal is detected,
the unit will display
the modbus timeout

Hum_Control = 2 or
3 only

humidifier operation
1 = Remotely
disables the

Selects the

Hum_Contr
ol

control type
that the
humidifier
operates on

40003

Holding

Register

Integer 0 - 3 - Write

1 = On/Off Signal
2 = RH Sensor Value
(Use Proportional
control method)
3 = RH Sensor Value
(Use Proportional­Integral control

Modbus Installation | 31

Switches

control signal

Indicates

stage 1

Indicates

stage 2

Indicates

stage 3

Indicates

status

Indicates

requirement

0 = No service

1 = Service required

Indicates fault
status

Input

Register

0 = No error
1 = Error(s) detected

Indicates

cycle status

Indicates

status

Displays

hours

Displays UV

hours

Displays unit

hours

Indicates

and 2)

Humidifier will only

1 = On

0 = Tank below full

1 = Tank full

Indicates

stages

NetSensor

Stage1Dem

Stage2Dem

Stage3Dem

Warning

Service

Fault

between hard
wired or
network

output from
humidifier

output from
humidifier

output from
humidifier

warning

maintenance

40002

30025

30026

30027

30015

30016

30017

Holding

Register

Input

Register

Input

Register

Input

Register

Input

Register

Input

Register

Integer 0 or 1 - Write

Integer 0 or 1 - Read

Integer 0 or 1 - Read

Integer 0 or 1 - Read

Integer 0 or 1 - Read

Integer 0 or 1 - Read

Integer 0 or 1 - Read

0 = Wired Analog
Sensor/Demand
1 = Modbus/Remote
Sensor/Demand

0 = Inactive
1 = Active

0 = Inactive
1 = Active

0 = Inactive
1 = Active

0 = No warning
1 = Warning

required

Cleaning

TankDrain

PumpRunHr

UVRunHr

ServTime

Security

TankLevel

automatic
stage cleaning

automatic
tank drain

pump
operational

lamp
operational

operational

security loop
status
(humidifier
terminals 1

Max Level
Sensor

30018

30019

30100

30101

30102

30200

30202

Input

Register

Input

Register

Input

Register

Input

Register

Input

Register

Input

Register

Input

Register

Integer 0 or 1 - Read

Integer 0 or 1 - Read

Integer

Integer

Integer

Integer 0 or 1 - Read

Integer 0 or 1 - Read

0 -

65535

0 -

65535

0 -

65535

10

min

10

min

10

min

Read

Read

Read

0 = Inactive
1 = Active

0 = Inactive
1 = Active

1Bit = 10min (max.
10’922h)

1Bit = 10min (max.
10’922h)

1Bit = 10min (max.
10’922h)

operate when
security loop is
closed.
0 = Off

level

System
Ready

32 |Modbus Installation

when the
humidifier is
ready to
commence

30013

Input

Register

Integer 0 or 1 - Read

0 = System busy
(cleaning or draining)
1 = System ready to
Humidify

1

2
3

Jumper Position

Function

J26 Removed

Terminal strip control

J26 Installed

Modbus control

Signaling Type

EIA-485

Transmission Mode

RTU

Baud Rate

9600 (can be changed to 4800 bps or 19200 bps)

Data Bits

8

Stop Bits

1

Parity

Even

Address / Unit Number

1*

MES2 and RH2 Models

The default Modbus address for a humidifier is 1.

To view or change the unit number:

Establish Modbus communications and map desired points as indicated in the following

table.

Read the current Modbus address from variable 40201.
Change this address by writing the desired value to 40201. Values of 1 – 255 are

acceptable.

By default the MES2 and RH2 are configured operate on a control signal supplied through the
unit terminal strip. This can be changed to allow the humidifier to function entirely through its
Modbus interface. This is configured by removed Jumper 26 from the humidifier circuit board.

MES2 and RH2 Electrode Steam OEM Humidifiers
The MES2 and RH2 both use the following parameters for communication:

*Default, may vary for multi-unit orders.

Modbus Installation | 33

Variable
Name

Description

Addr

Type

Format

Range

Unit

R/W

Details

0 = Disable operation of

Notes:

-

255 is written.

Imposes a

capacity.

0 = Normal operation

Notes:

normal operation.

Writes a

humidifier.

Default = 1. Values of 1 -

power cycled.

The following points may be mapped for control:

Configures
how

HumEnable

humidifier
responds to
modbus
controls

40003

Holding

Register

Integer 0,255 - Write

humidifier (Default Value)
255 = Allow operation of
humidifier within limits
specified by CapLimit

If a valid Modbus
message is not received
within the timeout
windows, this parameter
reverts to 0.

- This value cannot be set
when the FORCE DRAIN is
activated as. FORCE
DRAIN temporarily sets
this to value 0.

- Jumper J26 must be
installed to write any
parameter over the
Modbus. J26 sets it into
the control mode.

- Opening of the
hardwired security loop
(terminals 1 and 2) will
override operation even if

CapLimit

ForceDrain

ModAddress

maximum
output limit
as
percentage
of unit

Manually
initiates a
drain
period.

new
Modbus
address for
the

40004

40005

40201

Holding

Register

Holding

Register

Holding

Register

Integer

Integer 0, 255 - Write

Integer 1-255 - Write

25 ­100

% Write

Values outside of 25 ­100% return an error.
Default on startup = 25.

(Default)
255 = Initiate a 20
minute timer during which
the drain is active.

- During a force drain,
humidification ceases.

- Writing 0 during 20
minute period will cancel
the drain.

- After 20 minutes this
value will revert to 0 and
the humidifier will resume

255 are acceptable.
Changes to this variable
do not take effect until
the humidifier has been

34 |Modbus Installation

Changes to this variable

2 = 19200 bps

Changes to this variable

2 = Odd parity

Allows the

e.

Requires that HumEnable

operation is complete.

Switches

units.

Value represents

written as 5. (Default = 8)

Reads the jumper (J1 thru

installed)

0 = Single phase

2 = 3 phase (6 electrode)

do not take effect until

Baud

Parity

Sets the
Modbus
baud rate

Set Modbus
Parity

40202

40203

Holding

Register

Holding

Register

Integer 0,1,2 - Write

Integer 0,1,2 - Write

the humidifier has been
power cycled.
0 = 4800 bps
1 = 9600 bps (Default)

do not take effect until
the humidifier has been
power cycled.
0 = No parity
1 = Even parity (Default)

RunHrReset

Units

Model

run hour
counter to
be reset to
0, typically
used
following
maintenanc

between
imperial
(lbs/hr) and
metric
(kg/hr)

Allows
writing of
humidifier
capacity to
match
model.

40006

40204

40205

Holding

Register

Holding

Register

Holding

Register

Integer 0, 255 - Write

Integer 0,1 - Write

Integer 0 - 30 - Write

is set to 0 (disabled) first
or ILLEGAL DATA error will
occur.
255 = Reset the run time
hours (reported in
RunHrs) to 0.
Value reverts to 0 after

0 = Imperial (lbs/hr)
1 = Metric (kg/hr)
Changes values reported
in Model (40205) and
SteamOutput (30105).

maximum unit capacity, in
lbs/hr, at 100% Fill Off
Amps.
Value cannot be written
while HumEnable = 255
(operational).
The MES-005 would be

Voltage Unit voltage 40206

Phase

Unit voltage
phases

40207

Holding

Register

Holding

Register

Integer

Integer 0,1,2 - Write

1 to

10

- Write

6) pin settings and
reports the voltage:
0: 110-120V (J6 installed)
1: 208V (J6 installed)
2: 220-240V (J5 installed)
3: 230V
4: 277V (J4 installed)
5: 347V
6: 380V (J3 installed)
7: 400V (J3 installed)
8: 415V (J3 installed)
9: 440-480V (J2 installed,
Default)
10: 550-600V (J1

1 = 3 phase (Default)

Modbus Installation | 35

Write 255 to this register

read 0 (unit is disabled)

Each integer is a multiple

(disabled).

Each bit represents

in the register.

Units are defined in

in the register.

Steam production hours

12 = 60 minutes (1 hr)

Displays

version.

ForceReset

Resets the
controller
and restarts
in standby.

40007

Holding

Register

integer 0,255 - Write

to reset the control. The
controller will reset,
restart, and remain in
standby mode. After
completion:

- WasReset (40002 )will
read 255 (reset has
occurred)

- HumEnable (40003) will

TimeWindo
w

Current

SteamOutp
ut

Sets the
permissible
window for
modbus
data to be
written.

Displays
current
draw in
Amps.

Displays the
steam
output in
either
Metric of
Imperial
units.

40208

30104

30105

Holding

Register

Input

Register

Input

Register

Integer

Integer

Integer 0 - 300

0 -

255

0 -

12495

- Write

Amps Read

lbs/hr

kg/hr

Read

of 200mS. Maximum time
of 51 secs occurs when
the register reads 255.
A value of 0 disables the
timeout, but can only be
written with HumEnable
(40003) is set to 0

0.0024 Amps, therefore
1 Amp = 416 bits.
The Amp value does not
clear when security loop
is open and the
demand is 0. The last
detected value remains

Units (register 40204).
Unit includes decimal
point as integer value.
Example:
17 = 1.7 (kg/hr or
lbs/hr)
This variable does not
clear when the security
loop is open and the
demand 0. The last
detected value remains

RunHrs

Firmware

36 |Modbus Installation

Run hour
Counter

unit
firmware

30106

30113

Input

Register

Input

Register

Integer

Integer - - Read

0 -

24000

min Read

since last reset. Max
possible 2000 hrs of
operation. Each integer
is a multiple of 5
minutes. Example:
1 = 5minutes

Example: 352 = Version

3.52

Significant bits: 1 (Bit

active.

The maximum amount

Model (40205).

Values are displayed as

jumper J10 is installed.

0 = (Amber LED 1 flash)

End of cylinder life.

Uses significant bits 0

(0 = High Water)

Status

Displays
status of
various
components
.

30107

Input
Register

Integer 0 - 128 - Read

0), 2 (Bit 1), 4 (Bit 2), 8
(Bit 3), 16 (Bit 4), 32
(Bit 5), 64 (Bit 6), 128
(Bit 7).
Bit 0 = Contactor
Bit 1 = Fill Valve
Bit 2 = Drain Valve
Bit 3 = Blower pack fan
Bit 4 = Collective fault
(see 30108 for details)
Bit 5 = Humidifier Active
A “1” in the appropriate
bit location indicates
that the component is

MaxOutput

Modulation

FaultCode

Displays the
maximum
capacity of
humidifier.

Displays the
value of
modulating
signal when
a local
modulating
humidistat
is used.

Indicates
the
presence of
a fault and
which fault
has been
detected.

30111

30102

30108

Input
Register

Input
Register

Input
Register

Integer 0 - 30 lbs/hr Read

Integer

Integer

0­1023

0­32768

- Read

- Read

of steam per hour that
the humidifier can
produce in lbs/hr. This
value is copied from

whole numbers with 2
decimals places.
Example:
1023 = 10.23 volts
500 = 5.00 volts
A constant value of
1023 can indicate the

Excess current.
1 = (Amber LED 3 flash)
High water level, no
current.
2 = (Amber LED 2 flash)
No current detected
3 = (Amber LED 4 flash)

CtrlStatus1

Describes
controller
hardware
and jumper
statuses.

30109

Input
Register

Integer

0­32768

- Read

through 15 (1, 2, 4, 8,
16, 32, 64, 128, 256,
512, 1024, 2048,
4096, 8192, 16384,
32768 respectively).

Bit 1 - Electrodes
passing current (0 = On)
Bit 2 - FAULT Relay (0 =
On)
Bit 3 - YELLOW LED
(1 = Illuminated)
Bit 4 - GREEN LED
(0 = Illuminated)
Bit 5 - FAN (1 = On)
Bit 8 - High Water Input

Modbus Installation | 37

Bit 4 - MODBUS

Active)

CtrlStatus2

Hardware
status
Port D_E

30110

Input
Register

Integer

0­32768

- Read

Control Active
(0 = J26 installed)
Bit 9 - FILL (1 = Active)
Bit 10 - DRAIN (1 =

38 |Modbus Installation

Modbus Address

1
2
3
4
5

Control Signal Setting

1
2

1
2
3
4
5

NHRS Electric Steam Humidifiers

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

The default Modbus address for a NHRS is 1. If multiple units were included on an order, the
addresses of individual units may vary.

To view or change the unit number:

Press both the ↑ and ↓keys simultaneously to access the menu.
When prompted for a password, enter 8808 using the arrow keys.
Scroll through the menu until and select the Modbus Address.
Enter a value between 1 and 127 inclusive as desired.
Press both the ↑ and ↓keys simultaneously to return to the main menu.

This procedure is summarized below:

↑ and ↓ > 8808 > Modbus Address > 1 to 127

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 interface.

To adjust this setting:

Establish Modbus communications and map points as indicated in the following table.
Write a value of 1 to address 40039. A value of 1 indicates control through Modbus, a value

of 0 indicates controls hardwire to terminal strip.

The control type can also be modified:

Press both the ↑ and ↓keys simultaneously to access the menu.
When prompted for a password, enter 8808 using the arrow keys.
Scroll through the menu until and select the Controller Func.
Select Off for a demand type control, or On for sensor (transducer) control.
Press both the ↑ and ↓keys simultaneously to return to the main menu.

Modbus Installation | 39

Modbus Parameters

Signaling Type

EIA-485

Transmission Mode

RTU

Baud Rate

9600

Data Bits

8

Stop Bits

1

Parity

None

Address / Unit Number

1*

The NHRS uses the following parameters for communication:

*Default, may vary for multi-unit orders.

40 |Modbus Installation

Variable
Name

Description

Addr

Type

Format

Range

Unit

R/W

Details

Set a manual

for the humidifier

Limits output to

capacity

Write RH or Demand

humidifier

Writes the desired

controls

Switches between

signal

1 = Use Modbus to write

wired demand signal

Read RH or Demand

humidifier

Read space setpoint

controls only)

Reads the manual

for humidifier

1 = Use Modbus to write

wired demand signal

SysDeman
d

Read system ouput
/ demand

Input
Register

Displays output as
percentage of capacity

Read operation
hours of unit

Input
Register

0­infinity

Displays cumulative
hours since startup

Read minor

remaining

Read major

remaining

Read humidification
status

Input
Register

0 = Idle / Standby
1 = Active / Humidifying

Read service
warning status

Input
Register

0 = No Service Warning
1 = Service Required

Input
Register

0 = No Fault
1 = Fault Detected

0 = Demand Signal

("Transducer Control")

Read

status

0 = Communication Error

Communications

The following points may be mapped for control:

CapLimit

RHDem

Set

NetSensor

RHDem

Set

CapLimit

NetSensor

capacity restriction

signal value to

space setpoint
when using sensor

hard wired or
network control

signal value from

(sensor type

capacity restriction

Confirms humidifier
control mode

40006

40038

40024

40039

40008

40024

40006

40039

Holding
Register

Holding
Register

Holding
Register

Holding
Register

Input
Register

Input
Register

Input
Register

Input
Register

Integer 50-100 % Write

Integer 0-100 % Write

Integer 30-95 % Write

Integer 0,1 - Write

Integer 0-100 % Read

Integer 30-95 % Read

Integer 50-100 % Read

Integer 0,1 - Read

percentage of total

Requires network
controls (NetSensor = 1)

Use only when sending
RH value to RHDem

sensor or demand value
0 = Hard wired sensor or

Used with hardwired or
network control signal

Sensor controls only, not
for demand type controls

Adjust using writeable
CapLimit variable

sensor or demand value
0 = Hard wired sensor or

40007

HourOpt

SmallHrs

LargeHrs

Status

Service

Fault Read fault status 40035

InputType

Connection

maintenance hours

maintenance hours

Read control signal
mode

communication

40009

40013

40015

40036

40037

40025

40015

Input
Register

Input
Register

Input
Register

Input
Register

Integer 0-100 % Read

Integer

Integer 0-6000 hrs Read

Integer 0-6000 hrs Read

Integer 0,1 - Read

Integer 0,1 - Read

Integer 0,1 - Read

Integer 0,1 - Read

Integer 0,1 - Read

hrs Read

Displays hours until next
minor maintenance

Displays hours until next
major maintenance

1 = RH Sensor Signal

1 = Normal

Modbus Installation | 41

Problem

Resolutions

Check communication parameters. Nortec humidifiers are capable of Modbus RTU

necessary for some Modbus networks.

Check addresses, some Modbus network controllers automatically prepend the "40" for

depending on variable type.

Check the baud rate being used on the Modbus network. NH-EL, NHTC, GSTC, SETC,

once per minute.

Humidifier will not

over Modbus.

Check wire type and run length. Wire type should be 18 – 24 AWG, shielded twisted pair

should be of the same type (gas, electric, etc) but do not to be the same size.

Troubleshooting

Cannot see/change set
point over Modbus.

Cannot establish
communication.

Cannot read data from
point

Check control type. Demand type controls use internal algorithms to generate a signal
telling the humidifier to operate at a certain output percentage. These controls do not
report the detected humidity level or set point to the humidifier. As a result the set point
and space humidity levels cannot be monitored through Modbus when using demand
controls.

Sensor ("transducer") type controls report a sensed humidity value to the humidifier.
The set point is configured at the humidifier and the humidifier uses internal algorithms
to determine the output percentage. Since the humidifier knows both the set point and
humidity level, these values may be monitored over the Modbus connection.

communication. Modbus TCP based systems require a gateway to translate the
information.

Check Parity, baud rate, and stop bits. Modifying parity and stop bit parameters may be

input registers and "30" for input registers.

Carefully ensure that addresses are mapped correctly. A single incorrect address may
cause loss of communication or faults for an entire chain of humidifiers.

Check data type, some Modbus network controllers default to integer or binary values

MHTC, and NHRS units only support 9600 bps. MES-2 and RH2 units can support 4800

bps, 9600 bps, or 19200 bps for communications. Use of faster baud rates may cause
Only some registers
report data.

respond to set
point/sensor values/
demand values written

Humidifier will not
respond to hardwired
controls.

Intermittent
Communications

data loss.

Check the polling rate being used. High polling rates can interrupt responses from the

previous poll of data causing incomplete data transfer. A recommended polling rate is

Check that humidifier is configured for "Digital" or "Modbus" control.

Refer to the "Control Signal Settings" section for your humidifier model.

If the setting is "Analog" the humidifier will look for a control signal on the low voltage

terminal strip only.

Check that humidifier is configured for "Analog" control. Refer to the "Control Signal

Settings" section for your humidifier model. If the setting is "Digital" or "Modbus" the

humidifier will look for a control value to be written over Modbus only.

wire with 120 ohm characteristic impedance. Chains should not exceed 2000 feet in

length.

Look for wire runs in close proximity to equipment generating significant electrical noise

(such as VFD's, medical equipment, X-ray machinery, servers, etc).

Check that wire shield is terminated at one end only. Terminations at both ends cause

shield to conduct electricity and can generate noise.

Confirm correct polarity of conductors at each device. This problem can be the result of

Net+ and Net- terminals being crossed.

Check Modbus addresses for conflicts with any device. Each Modbus device on the

network must have a unique address. Devices (humidifiers or otherwise) cannot share

Modbus addresses.

Ensure that no more than 8 devices are connected to a single chain/bus. Humidifiers

42 |Modbus Installation

More variables or

humidifier.

This error is generated in cases where the humidifier is configured for control over the

found earlier in this manual.

Step A – Unpacking

Step B – Hardware installation

1

2

Invalid data

additional information
is required from the

NHTC / GSTC / SETC
E-50 Error

MHTC
E-35 Error

“Modbus Timeout”

Appendix A

Check Modbus addresses for conflicts. Each Modbus device on the network must have
a unique address. Devices (humidifiers or otherwise) cannot share Modbus addresses.

Contact Nortec Technical Services for additional support.

Modbus network and a value is not written without the timeout window. The timeout
clock restarts each time a value is written (even if the same value is written repeatedly).

The error is corrected by writing an appropriate value to the RHdem1 address:
NH-EL - 40005
NHTC – 40264
GSTC – 40264
SETC – 40264
MHTC – 40053

If it is desired to use hardwired controls instead of network controls, the humidifier must
be configured as such. Refer to the Control Signal Setting section for your humidifier

Modbus – Field Retrofit for NHRS Models

The Field kit is used to provide a simple hardware interface between the humidifier and Modbus
BMS RS485 connection. Because the NHRS Humidifier speaks a different language, a
Translation card is provided with the hardware kit. First start by reviewing the contents of
Modbus Field retrofit kit, you should have the following items:

 1 Ribbon cable 10 pin to 20 pin
 1 Translation Printed Circuit board (colour blue)
 1 terminal strip (3 pole) with RJ 11 termination cable
 4 Nylon Standoffs (white)
 4 Nylon screws (white)

Locate the main PCB board inside the humidifier.
Connect one end of the ribbon cable (10 pin end) to the Humidifier’s COM port.

Modbus Installation | 43

Figure 7: Humidifier COM port

3 Route the ribbon cable through the punch out on the humidifiers front electrical panel

Figure 8: Routing of Ribbon Cable

44 |Modbus Installation

4

5

20 pin connection

Connect the ribbon cable 20 pin side to the Logic Card.

Figure 9: Pin connection for Ribbon cable

Configured dipswitch settings according to MODE1 printed on card (485<>TTL).

Figure 10: Dipswitch settings for Logic Card

Modbus Installation | 45

7

6 Connect the RJ-11 cable to the corresponding jack on the logic card.

Figure 11: RJ-11 Jack Location on Logic Card

Mount logic card with nylon standoffs and screws to humidifier using the 4 pre-drilled

holes

46 |Modbus Installation

Figure 12: Pre drilled holes for Logic card

8

Mount the Terminal strip (3 pole) below or above the existing NHRS low voltage

terminal strip

Figure 13: Low voltage terminal strip on NHRS Humidifier

Modbus Installation | 47

Warranty

Nortec Humidity Inc. and/or Nortec Humidity Ltd. (hereinafter collectively referred to as THE
COMPANY), warrant for a period of two years after installation or 30 months from
manufacturer’s ship date, whichever date is earlier, that THE COMPANY’s manufactured and
assembled products, not otherwise expressly warranted (with the exception of the cylinder), are
free from defects in material and workmanship. No warranty is made against corrosion,
deterioration, or suitability of substituted materials used as a result of compliance with
government regulations.

THE COMPANY’s obligations and liabilities under this warranty are limited to furnishing
replacement parts to the customer, F.O.B. THE COMPANY’s factory, providing the defective
part(s) is returned freight prepaid by the customer. Parts used for repairs are warranted for the
balance of the term of the warranty on the original humidifier or 90 days, whichever is longer.

The warranties set forth herein are in lieu of all other warranties expressed or implied by law. No
liability whatsoever shall be attached to THE COMPANY until said products have been paid for in
full and then said liability shall be limited to the original purchase price for the product. Any
further warranty must be in writing, signed by an officer of THE COMPANY.

THE COMPANY’s limited warranty on accessories, not of the companies manufacture, such as
controls, humidistats, pumps, etc. is limited to the warranty of the original equipment
manufacturer from date of original shipment of humidifier.

THE COMPANY makes no warranty and assumes no liability unless the equipment is installed in
strict accordance with a copy of the catalog and installation manual in effect at the date of
purchase and by a contractor approved by THE COMPANY to install such equipment.

THE COMPANY makes no warranty and assumes no liability whatsoever for consequential
damage or damage resulting directly from misapplication, incorrect sizing or lack of proper
maintenance of the equipment.

THE COMPANY makes no warranty and assumes no liability whatsoever for damage resulting
from freezing of the humidifier, supply lines, drain lines, or steam distribution systems.

THE COMPANY retains the right to change the design, specification and performance criteria of
its products without notice or obligation.

48 |Modbus Installation

U.S.A.

2700 90
Sturtevant, WI 53177

835 Commerce Park Dr.
Ogdensburg, NY 13669-2209

CANADA

2740 Fenton Road
Ottawa, Ontario K1T 3T7

TEL: 1.866.NORTEC1
FAX: [phone]

EMAIL: [e-mail]
WEBSITE: www.humidity.com

th

St.