Appendix 1: modbus register map – Super Systems H2 Sensor User Manual
Page 14

Hydrogen (H
2
) Sensor Operations Manual
Super Systems Inc.
Page 14 of 17
Appendix 1: Modbus Register Map
Register Functions and Default Values
#
Function
Default
0 Current firmware revision level
Varies
1 RS-232 communication mode (0=Modbus slave, 1=ASCII /Previous SSI
Sensor)
DIP Sw.
2 RS-232 baud rate (0=9600, 1=19200, 2=38400)
0
3 RS-485 communication mode (0=Modbus slave, 1=Modbus master [NOT
USED])
0
4 RS-485 baud rate (0=9600, 1=19200, 2=38400)
1
5 Temperature trim for thermistor 1 / ambient temperature
200
6 A/d counts for thermistor 1
Varies
7 Thermistor 1 temperature
Varies
8 %H2 A/D counts – High (Right justified: 0x00 byte, high byte, mid byte,
low byte)
Varies
9 %H2 A/D counts – Low (Right justified: 0x00 byte, high byte, mid byte, low
byte)
Varies
10 %H2 measured voltage
Varies
11 %H2 as found from a polynomial
Varies
12 %H2 sensor calibration (0=none, 1=zero cal, 2=span cal)
0
13 %H2 gas composition (value/100 = %H2/N2 balance)
0
14 Sensor Modbus address (important for slave communications only)
DIP Sw.
15 Model Number
4100
16 Set Factory Defaults (23205=Full, 23206=%H2, 23207=Loop 1, 23208 =
Loop 2)
0
17 4-20mA #1 DAC output counts
Varies
18 4-20mA #2 DAC output counts
Varies
19 4-20mA #1 Source (0=%H2, 1=%DA, 2=%NH3, 3=Kn, 4= External)
0
20 4-20mA #1 Zero value
Varies
21 4-20mA #1 Span Value
10000
22 4-20mA #1 External current loop (Used only if register 19 = 4)
0
23 4-20mA #2 Source (0=%H2, 1=%DA, 2=%NH3, 3=Kn, 4= External)
1
24 4-20mA #2 Zero value
0
25 4-20mA #2 Span Value
1000
26 4-20mA #2 External current loop (Used only if register 23 = 4)
0
27 Enable Calibration of 4-20ma output (0=disable, 1=enable)
0
28 Calibrate 4-20mA output (1=#1 zero, 2=#1 span, 3=#2 zero, 4=#2 span)
0
29 4-20mA calibration value (4000 to 20000 for 4-20mA)
0
30 Calibration result codes (9-12=successes, 13-16=failures, 20=no cal
specified)
0
31 Percent DA value
Varies
32 Percent NH
3
value
Varies
33 Super Kn value
Varies
34 %N
2
flow
0
35 %NH
3
flow
0
36 %DA flow
0