neptronic CMU-Modbus Compact Make-up Air Unit User Guide

: June 3, 2024
: neptronic

Table of Contents

neptronic CMU-Modbus Compact Make-up Air Unit
Introduction
Holding Registers Table
References
Read User Manual Online (PDF format)
Download This Manual (PDF format)

neptronic CMU-Modbus Compact Make-up Air Unit

neptronic-CMU-Modbus-Compact-M

Introduction

The Compact Make-up Air Unit Modbus Communication Module User Guide provides information for using the Neptronic communication feature. The controller uses Modbus communication protocol over a serial line in the RTU mode and provides a Modbus network interface between client devices and Neptronic Compact Make- up Air Unit devices. The Compact Make-up Air Unit Modbus Guide assumes that you are familiar with Modbus terminology. The following are the requirements for Modbus:

Data Model. The Compact Make-up Air Unit Modbus server data model uses only the Holding Registers table.
Register Address:
- As per the protocol base (base 0); for PLC add 1 to the protocol base.
- As per the holding register (base 40001).
Function Codes. The Compact Make-up Air Unit Modbus server supports a limited function codes subset comprising:
- Read Holding Registers (0x03)
- Write Single Register (0x06)
- Write Multiple Registers (0x10)
Exception Responses. The Compact Make-up Air Unit Modbus server supports the following exception codes:
- Illegal data address
- Illegal data value
- Slave device busy
Serial Line. The Compact Make-up Air Unit Modbus over serial line uses RTU transmission mode over a two-wire configuration RS485 (EIA/TIA-485 standard) physical layer.
- The physical layer can use fixed baud rate selection or automatic baud rate detection (default) as per the Modbus Auto Baud Rate device menu item or holding register index 1.
- The supported baud rates are 9600, 19200, 38400, 57600, and 76800 bps.
- The physical layer also supports variable parity control and stop-bit configuration as per the Modbus Comport Config device menu item or holding register index 2.
- In auto baud rate configuration, if the device detects only consecutive bad frames (2 or more) for one second with any given baud rate, it will reinitialize itself to the next baud rate.
- If the device does not detect any activity for one second or more, it will find a silent line to prevent a possible baud rate scan on the next frame it detects.
Addressing. The Compact Make-up Air Unit device only answers at the following address:
- The device’s unique address (1 to 247) can be set through the device menu or by holding the register index

Holding Registers Table

Glossary

Name	Description	Name	Description
W	Writable Register	ASCII	For registers containing ASCII (8-bit) characters
RO	Read Only Register	MSB	Most Significant Byte
Unsigned	For range of values from 0 to 65,535, unless otherwise specified
LSB	Least Significant Byte
Signed	For range of values from -32,768 to 32,767, unless otherwise
specified	MSW	Most Significant Word
Bit String	For registers with multiple values using bit mask (example,
flags)	LSW	Least Significant Word

Holding Register Table

Protocol Base| Holding Register| ****

Description

| ****

Data Type

| ****

Range

| ****

Writable

---|---|---|---|---|---
0| 4000 1| Modbus product type and address.| Unsigned| MB = Modbus Address (e.g. 110), LB = 1-247| W
1| 4000 2| Analog input 1 voltage.| Unsigned

Scale 1000

| Unit: Volts (V), Range: 0V to 10V

Value x 1000 (e.g. 2V = 2000)

| RO
2| 4000 3| Analog input 2 voltage.| Unsigned

Scale 1000

| Unit: Volts (V), Range: 0V to 10V

Value x 1000 (e.g. 2V = 2000)

| RO
3| 4000 4| Analog input 3 temperature.| Signed

Scale 100

| Units: °C/°F, Range: -40°C to 85°C or -40°F to 185°F

Value x 100 (e.g. 25°C = 2500 or 25°F = 2500)

| RO
4| 4000 5| Analog input 4 temperature.| Signed

Scale 100

| Units: °C/°F, Range: -40°C to 85°C or -40°F to 185°F

Value x 100 (e.g. 25°C = 2500 or 25°F = 2500)

| RO
5| 4000 6| Room air temperature value measured by TDF.| Unsigned

Scale 100

| Units: °C/°F, Range : 0°C to 50°C or 32°F to 122°F

Value x 100 (e.g. 5°C = 500 or 50°F = 5000)

| RO
6| 4000 7| Room air relative humidity value measured by TDF.| Unsigned

Scale 10

| Unit: %RH, Range: 0 to 100%RH

Value x 10 (e.g. 10%RH = 100)

| RO
7| 4000 8| Room CO2 concentration value measured by TDF.| Unsigned

Scale 1

| Unit: PPM, Range: 0 to 2000 PPM

Value x 1 (e.g. 2 PPM = 2)

| RO
8| 4000 9| The volatile organic compound index measured by TDF.| Unsigned

Scale 1

| Unit: No Unit, Range: 0 to 65535,

Value x 1 (e.g. 100 = 100)

| RO
Protocol Base| Holding Register| ****

Description

| ****

Data Type

| ****

Range

| ****

Writable

---|---|---|---|---|---
9| 400 10| Luminous flux measured by TDF.| Unsigned

Scale 1

| Unit: Lux, Range: 0 to 16000 Lux

Value x 1 (e.g. 2 Lux = 2)

| RO
10| 400 11| CMU on-board potentiometer temperature setpoint.| Unsigned

Scale 100

| Units: °C/°F, Range: 0°C to 35°C or 32°F to 95°F

Value x 100 (e.g. 2°C = 200 or 50°F = 5000)

| RO
11| 400 12| CMU intake temperature.| Signed

Scale 100

| Units: °C/°F, Range: -40ºC to 85ºC or -40°F to 185°F

Value x 100 (e.g. 23°C = 2300 or 23°F = 2300)

| RO
12| 400 13| CMU outtake temperature.| Signed

Scale 100

| Units: °C/°F, Range: -40ºC to 85ºC or -40°F to 185°F

Value x 100 (e.g. 23°C = 2300 or 23°F = 2300)

| RO
13| 400 14| CMU board temperature.| Signed

Scale 100

| Units: °C/°F, Range: -40ºC to 85ºC or -40°F to 185°F

Value x 100 (e.g. 23°C = 2300 or 23°F = 2300)

| RO
14| 400 15| CMU SSR temperature.| Signed

Scale 100

| Units: °C/°F, Range: -40ºC to 85ºC or -40°F to 185°F

Value x 100 (e.g. 23°C = 2300 or 23°F = 2300)

| RO
15| 400 16| AI3/BI3 multi-mode input state.| Unsigned| 0 = Open, 1 = Closed| RO
16| 400 17| AI4/BI4 multi-mode input state.| Unsigned| 0 = Open, 1 = Closed| RO
17| 400 18| Room movement detection occupancy sensor.| Unsigned| 0 = No, 1 = Yes| RO
18| 400 19| CMU On/Off contact input state.| Unsigned| 0 = Off, 1 = On| RO
19| 400 20| Analog output 1 voltage.| Unsigned

Scale 100

| Unit: Volts, Range: 0V to 10V

Value x 100 (e.g. 3V = 300)

| RO
20| 400 21| Analog output 2 voltage.| Unsigned

Scale 100

| Unit: Volts, Range: 0V to 10V

Value x 100 (e.g. 3V = 300)

| RO
21| 400 22| Binary output 1 state.| Unsigned| 0 = Open, 1 = Closed| RO
22| 400 23| Binary output 1 state.| Unsigned| 0 = Open, 1 = Closed| RO
23| 400 24| Supply air temperature.| Unsigned

Scale 100

| Units: °C/°F, Range: 0°C to 100°C or 32°F to 212°F

Value x 100 (e.g. 2°C = 200 or 50°F = 5000)

| RO
24| 400 25| Supply air relative humidity.| Unsigned

Scale 100

| Units: %RH, Range: 0 to 100%RH

Value x 100 (e.g. 23%RH = 2300)

| RO
25| 400 26| Outside air temperature.| Signed

Scale 100

| Units: °C/°F, Range: -40ºC to 50ºC or -40°F to 122°F

Value x 100 (e.g. 23°C = 2300 or 23°F = 2300)

| RO
26| 400 27| Outside air relative humidity.| Unsigned

Scale 100

| Units: %RH, Range: 0 to 100%RH

Value x 100 (e.g. 23%RH = 2300)

| RO
27| 400 28| Duct static pressure.| Unsigned

Scale 10

| Units: Pascal (Pa), Range: 0 to 1250 Pa

Value x 10 (e.g. 50 Pa = 500)

| RO
Protocol Base| Holding Register| ****

Description

| ****

Data Type

| ****

Range

| ****

Writable

---|---|---|---|---|---
28| 400 29| Damper position feedback.| Unsigned

Scale 1

| Unit: %, Range: 0% to 100%,

Value x 1 (e.g. 100% = 100)

| RO
29| 400 30| Current airflow setpoint in percent of maximum capacity.| Unsigned

Scale 1

| Unit: %, Range: 0% to 100%,

Value x 1 (e.g. 100% = 100)

| RO
30| 400 31| CMU ECM fan speed feedback value.| Unsigned

Scale 1

| Unit: RPM, Range: 0 to 10000 RPM,

Value x 1 (e.g. 100 RPM = 100)

| RO
31| 400 32| Heater vernier stage duty cycle.| Unsigned

Scale 10

| Unit: %, Range: 0 to 100%,

Value x 10 (e.g. 100% = 1000)

| RO
32| 400 33| Network temperature setpoint.| Unsigned

Scale 100

| Unit: °C/°F, Range: 0°C to 35°C or 32°F to 95°F,

Value x 1 (e.g. 5°C = 500 or 50°F = 5000)

| W
33| 400 34| TDF temperature setpoint.| Unsigned

Scale 100

| Unit: °C/°F, Range: 0°C to 35°C or 32°F to 95°F,

Value x 1 (e.g. 5°C = 500 or 50°F = 5000)

| W
34| 400 35| CMU anti-freeze setpoint.| Unsigned

Scale 100

| Unit: °C/°F, Range: 0°C to 35°C or 32°F to 95°F,

Value x 1 (e.g. 5°C = 500 or 50°F = 5000)

| W
35| 400 36| Occupied airflow setpoint in percent of maximum capacity.| Unsigned

Scale 1

| Unit: %, Range: 0 to 100%,

Value x 1 (e.g. 100% = 100)

| W
36| 400 37| Unoccupied airflow setpoint in percent of maximum capacity.| Unsigned

Scale 1

| Unit: %, Range: 0 to 100%,

Value x 1 (e.g. 100% = 100)

| W
37| 400 38| Binary input 3 stage weight.| Unsigned

Scale 1

| Unit: %, Range: 0 to 100%,

Value x 1 (e.g. 100% = 100)

| W
38| 400 39| Binary input 4 stage weight.| Unsigned

Scale 1

| Unit: %, Range: 0 to 100%,

Value x 1 (e.g. 100% = 100)

| W
39| 400 40| Exhaust fan start delay.| Unsigned

Scale 1

| Unit: Seconds, Range: 1 to 255 seconds

Value x 1 (e.g. 10 secs = 10)

| W
40| 400 41| Exhaust fan control signal minimum value.| Unsigned

Scale 100

| Unit: Volts (V), Range: 0 to 10V,

Value x 100 (e.g. 3V = 300)

| W
41| 400 42| Exhaust fan control signal maximum value.| Unsigned

Scale 100

| Unit: Volts (V), Range: 0 to 10V,

Value x 100 (e.g. 3V = 300)

| W
42| 400 43| Damper stroke time.| Unsigned

Scale 1

| Unit: Seconds, Range: 1 to 255 seconds,

Value x 1 (e.g. 100 secs = 100)

| W
43| 400 44| Occupancy inputs minimum time.| Unsigned

Scale 1

| Unit: Minutes, Range: 0 to 240 minutes,

Value x 1 (e.g. 10 mins = 10)

| W
Protocol Base| Holding Register| ****

Description

| ****

Data Type

| ****

Range

| ****

Writable

---|---|---|---|---|---
44| 400 45| Temperature setpoint minimum value.| Unsigned

Scale 100

| Unit: °C/°F, Range: 0°C to 35°C or 32°F to 95°F,

Value x 1 (e.g. 5°C = 500 or 50°F = 5000)

| W
45| 400 46| Temperature setpoint maximum value.| Unsigned

Scale 100

| Unit: °C/°F, Range: 0°C to 35°C or 32°F to 95°F,

Value x 1 (e.g. 5°C = 500 or 50°F = 5000)

| W
46| 400 47| Dry mode relative humidity setpoint.| Unsigned

Scale 1

| Unit: %RH, Range: 10 to 90%RH

Value x 1 (e.g. 10%RH = 10)

| W
47| 400 48| Dry mode relative humidity setpoint dead band.| Unsigned

Scale 1

| Unit: %RH, Range: 1 to 10%RH

Value x 1 (e.g. 10%RH = 10)

| W
48| 400 49| Occupied static pressure control loop setpoint.| Unsigned

Scale 10

| Unit: Pascal (Pa), Range: 0 to 1250 Pa

Value x 10 (e.g. 3 Pa = 30)

| W
49| 400 50| Unoccupied static pressure control loop setpoint.| Unsigned

Scale 10

| Unit: Pascal (Pa), Range: 0 to 1250 Pa

Value x 10 (e.g. 3 Pa = 30)

| W
50| 400 51| CO2 concentration setpoint.| Unsigned

Scale 1

| Unit : PPM, Range : 0 to 1000 PPM

Value x 1 (e.g. 3 PPM = 3)

| W
51| 400 52| CO2 concentration setpoint dead band.| Unsigned

Scale 1

| Unit : PPM, Range : 0 to 200 PPM

Value x 1 (e.g. 3 PPM = 3)

| W
52| 400 53| Supply air temperature offset.| Signed

Scale 100

| Unit: °C/°F, Range: ± 5ºC or +/-9ºF

Value x 100 (e.g. 2ºC = 200 or 3ºF = 300)

| W
53| 400 54| Supply air temperature humidity offset.| Signed

Scale 100

Scale 100

| Unit: °C/°F, Range: ± 5ºC or +/-9ºF

Value x 100 (e.g. 2ºC = 200 or 3ºF = 300)

| W
55| 400 56| Outside air temperature humidity offset.| Signed

Scale 100

Scale 100

Scale 100

Scale 10

Scale 1

| Unit: %, Range: 0 to 100%

Value x 1 (e.g. 3% = 3)

| W
Protocol Base| Holding Register| ****

Description

| ****

Data Type

| ****

Range

| ****

Writable

---|---|---|---|---|---
60| 400 61| Temperature control proportional band.| Unsigned

Scale 100

| Unit: °C/°F, Range: 0.5°C to 20°C or 33°F to 68°F,

Value x 100 (e.g. 5°C = 500 or 50°F = 5000)

| W
61| 400 62| Temperature control integral time.| Unsigned

Scale 1

| Unit: Seconds, Range: 0 to 255 seconds,

Value x 1 (e.g. 100 secs = 100)

| W
62| 400 63| Temperature control derivate time.| Unsigned

Scale 1

| Unit: Seconds, Range: 0 to 255 seconds,

Value x 1 (e.g. 100 secs = 100)

| W
63| 400 64| Static pressure control proportional band.| Unsigned

Scale 1

| Unit: Pascal (Pa), Range: 0 to 250 Pa

Value x 1 (e.g. 3 Pa = 3)

| W
64| 400 65| Static pressure control integral time.| Unsigned

Scale 1

| Unit: Seconds, Range: 0 to 255 seconds,

Value x 1 (e.g. 100 secs = 100)

| W
65| 400 66| Static pressure control derivate time.| Unsigned

Scale 1

| Unit: Seconds, Range: 0 to 255 seconds,

Value x 1 (e.g. 100 secs = 100)

| W
66| 400 67| Control band.| Unsigned

Scale 100

| Unit: °C/°F, Range: 2°C to 10°C or 36°F to 50°F,

Value x 100 (e.g. 5°C = 500 or 50°F = 5000)

| W
67| 400 68| Modbus timeout.| Unsigned

Scale 1

| Unit: Seconds, Range: 15 to 1800 seconds,

Value x 1 (e.g. 100 secs = 100)

| W
68| 400 69| Number of synchronization timeouts.| Unsigned

Scale 1

| Unit: No Unit, Range: 0 to 65535,

Value x 1 (e.g. 100 = 100)

| W
69| 400 70| No heat detection deadband.| Unsigned

Scale 100

| Unit: °C/°F, Range: 2°C to 8°C or 36°F to 46°F,

Value x 100 (e.g. 5°C = 500 or 5°F = 500)

| W
70| 400 71| No heat detection delay.| Unsigned

Scale 1

| Unit: Seconds, Range: 30 to 240 seconds,

Value x 1 (e.g. 100 secs = 100)

Description

| ****

Data Type

| ****

Range

| ****

Writable

---|---|---|---|---|---
80| 400 81| Enable occupancy inputs.| Unsigned| 0 = No, 1 = Yes| W
81| 400 82| Dry mode.| Unsigned| 0 = Disable, 1 = Enable| W
82| 400 83| CO2 extract.| Unsigned| 0 = Disable, 1 = Enable| W
83| 400 84| Static pressure loop.| Unsigned| 0 = Disable, 1 = Enable| W
84| 400 85| Occupancy inactive mode.| Unsigned| 0 = Unoccupied, 1 = Off| W
85| 400 86| CMU occupancy state.| Unsigned| 1 = Occupied | 2 = Unoccupied | 3 = Off| W
86| 400 87| Temperature setpoint source.| Unsigned| 1 = On Board | 2 = TSTAT | 3 = Network| W
87| 400 88| AI1 input mode.| Unsigned| 1 = Off | 2 = SAT | 3 = SARH | 4 = OAT | 5 = OARH | 6 = Static Pressure | 7 = Fan Setpoint | 8 = Damper Feedback| W
88| 400 89| AI2 input mode.| Unsigned| 1 = Off | 2 = SAT | 3 = SARH | 4 = OAT | 5 = OARH | 6 = Static Pressure | 7 = Fan Setpoint | 8 = Damper Feedback| W
89| 400 90| AI3/BI3 input mode.| Unsigned| 1 = Off | 2 = SAT | 3 = OAT | 4 = Damper Feedback | 5 = Occupancy | 6 = Fan Speed Stage| W
90| 400 91| AI4/BI4 input mode.| Unsigned| 1 = Off | 2 = SAT | 3 = OAT | 4 = Damper Feedback | 5 = Occupancy | 6 = Fan Speed Stage| W
91| 400 92| AO1 output mode.| Unsigned| 1 = Off | 2 = Exhaust Fan | 3 = Damper| W
92| 400 93| AO2 output mode.| Unsigned| 1 = Off | 2 = Exhaust Fan | 3 = Damper| W
93| 400 94| BO1 output mode.| Unsigned| 1 = Off | 2 = Exhaust Fan | 3 = Damper| W
94| 400 95| BO2 output mode.| Unsigned| 1 = Off | 2 = Exhaust Fan | 3 = Damper| W
95| 400 96| Static pressure sensor range.| Unsigned| 1 = 250 Pa | 2 = 500 Pa | 3 = 1250 Pa| W
96| 400 97| Analog input 1 signal range.| Unsigned| 1 = 2-10Vdc | 2 = 0-10Vdc| W
97| 400 98| Analog input 2 signal range.| Unsigned| 1 = 2-10Vdc | 2 = 0-10Vdc| W
98| 400 99| Analog output 1 signal range.| Unsigned| 1 = 2-10Vdc | 2 = 0-10Vdc| W
99| 40 100| Analog output 2 signal range.| Unsigned| 1 = 2-10Vdc | 2 = 0-10Vdc| W
100| 40 101| Control temperature source.| Unsigned| 1 = SAT | 2 = RAT| W
101| 40 102| LCD screen top line value.| Unsigned| 1 = None | 2 = Time | 3 = CO2 | 4 = SARH | 5 = RARH| W
102| 40 103| LCD screen displayed temperature.| Unsigned| 1 = Default | 2 = Alternate | 3 = SAT | 4 = TSTAT| W
103| 40 104| LCD screen last reset reason.| Unsigned| 1 = No reason | 2 = Independent Watchdog | 3 = Window Watchdog | 4 = Software Reset | 5 = Power Down| RO
Protocol Base| Holding Register| ****

Description

| ****

Data Type

| ****

Range

| ****

Writable

---|---|---|---|---|---

104

| ****

40 105

| ****

Alarm status.

| ****

Bit String

| B0 = Unblocking Damper Required B1 = SSOR1 Sens Not Detected B2 = SSOR2 Sens Not Required B3 = SAT Not Detected

B4 = RAT Not Detected

| B5 = Timeout Comm B6 = AI1 Reading Error B7 = AI2 Reading Error

B8 to B31 = Reserved

| ****

RO

105

| ****

40 106

| ****

System alarm host.

| ****

Bit String

| B0 = Thermal Cutout B1 = Comm Timeout

B3 = Heater Temp Cutout B4 = SSR Temp Cutout B5 = Board Temp Cutout B6 = Duct Temp Cutout

B7 = Heater Temp 1 Failure B8 = Heater Temp 2 Failure B9 = Board Temp Failure B10 = SSR Temp Failure

| B11 = TRL Failure B13 = Invalid Config

B14 = Fan Temp Failure B16 = External Temp Failure B17 = Supply Temp Failure B22 = Fan Feedback Error B30 = Air Flow Not Detected B31 = Heat Not Detected

B2, B12, B15, B18 to B21, B23

to B29 = Reserved

| ****

RO

400 Lebeau blvd, Montreal, Qc, H4N 1R6, Canada www.neptronic.com
Toll-free in North America: 1-800-361-2308
Tel.: 514-333-1433
Fax: 514-333-3163
Customer service fax: 514-333-1091
Monday to Friday: 8:00 am to 5:00 pm (Eastern time)