
SARB Networkable IAQ Room Sensors
Specification and Installation Instructions
www.neptronic.com
Page | 10
Holding Register Table
Regi
ster
Index
Description
Data
Type
Range
Writa
ble
4000
0
MSB = Neptronic ID
LSB = Modbus address of current device
Unsigned
MSB = 18
LSB = 1-246
W
4000
1
MSTP Baud Rate
Unsigned
Scale 100
0, 9600, 19200, 38400, or 57600, 0 = Auto Baud Rate Detection
Value/100 (e.g. 38400 baud = 384)
W
4000
2
Communication port configuration
Unsigned
0 = No parity, 2 Stop bits
1 = Even parity, 1 stop bit
2 = Odd parity, 1 stop bit
W
4000
3
Product Name (characters 1 & 2)
ASCII
1 to 65535 | MSB = char 1, LSB = char 2
W
4000
4
Product Name (characters 3 & 4)
ASCII
1 to 65535 | MSB = char 3, LSB = char 4
W
4000
5
Product Name (characters 5 & 6).
ASCII
1 to 65535 | MSB = char 5, LSB = char 6
W
4000
6
Product Name (characters 7 & 8).
ASCII
1 to 65535 | MSB = char 7, LSB = char 8
W
4000
7
Actual firmware version
Unsigned
1 to 65535 (e.g. 101)
RO
4000
8
Actual ROM version
Unsigned
1 to 65535 (e.g. 123)
RO
4000
9
Alarms Status 1
Bit String
[B0 – B15]
:
Reserved
RO
400
10
Alarms Status 2
Bit String
[B0 – B15]
:
Reserved
RO
400
11
CO2 Level
Unsigned
0 to 2000 ppm
RO
400
12
VOC Level
Unsigned
0 to 1000 ppb
RO
400
13
Temperature Level
Signed
Scale 10
Unit: ºC/ºF, Range: -40ºC to 125ºC or -40ºF to 257ºF
Value x 10 (e.g. 23°C = 230 or 33ºF = 330)
RO
400
14
Humidity Level
Signed
Scale 10
Unit: % RH, Range: 0%RH to 100%RH
Value x 10 (e.g. 30%RH = 300)
RO
400
15
Reserved
400
16
Enthalpy
Signed
Scale 100
Unit: kJ/kg, -327 kJ/kg to 327 kJ/kg
Unit: BTU/lb, -133 BTU/lb to 148 BTU/lb
Value x 100 (e.g. 105.75 kJ/kg = 10575)
RO
400
17
Dew Point
Signed
Scale 10
Unit: ºC/ºF, Range: -40ºC to 125ºC or -40ºF to 257ºF
Value x 10 (e.g. 23°C = 230 or 33ºF = 330)
RO
400
18
External Temperature Level
Signed
Scale 10
Unit: ºC/ºF, Range: -40ºC to 125ºC or -40ºF to 257ºF
Value x 10 (e.g. 23°C = 230 or 33ºF = 330)
Register 32 must be set to 10kOhms
RO
400
19
AI1
Unsigned
Scale 100
0 to 1000
Value x 100 (e.g. 2 mV = 200)
Register 32 must be set to 0-10V
RO
400
20
BI1
Unsigned
0 = Opened; 1 = Closed
RO
400
21
CO2 Calibration
Signed
-200 to 200 ppm
W
400
22
VOC Calibration
Signed
-100 to 100 ppb
W
400
23
Temperature Calibration
Signed
Scale 100
Unit: ºC/ºF, Range: -10ºC to 10ºC or -18ºF to 18ºF
Value x 100 (e.g. 5°C = 500 or 10ºF = 1000)
W
400
24
Humidity Calibration
Signed
Scale 100
Unit: %, Range: -10% to 10%
Value x 100 (e.g. 5% = 500)
W
400
25
Reserved
400
26
External Temperature Sensor Calibration
Signed
Scale 100
Unit: ºC/ºF, Range: -10ºC to 10ºC or -18ºF to 18ºF
Value x 100 (e.g. 5°C = 500 or 10ºF = 1000)
Register 32 must be set to 10kOhms
W
400
27
AO1
Unsigned
Scale 10
Unit: %, Range: 0% to 100%
Value x 10 (e.g. 30% = 300)
W