Vaisala Indigo500 Series - Appendix A. Modbus Reference; A.1 Unit IDs; A.2 Function Codes; A.3 Device Identification Objects

Appendix A. Modbus reference
A.1 Unit IDs
Table 32 Unit IDs of transmitter and probes
Device Unit ID
Transmitter (including analog input and optional
barometer module)
240
Probe connected to probe 1 connection terminal 241
Probe connected to probe 2 connection terminal 242
For probe-specific register information, see the connected probe's Modbus
documentation.
A.2 Function codes
Table 33 Modbus function codes
Function
code
(decimal)
Function code
(hexadecimal)
Name Notes
03 03
hex
Read Holding
Registers
Can be used for reading pressure value
using unit ID 240, and for reading probe
registers, for example, measurement
results, using unit ID 241 or 242.
1)
43 / 14 2B
hex
/ 0E
hex
Read Device
Identification
Can be used only for reading transmitter
identification information using unit ID
240.
1) See the connected probe's Modbus documentation for a probe-specific register list.
A.3 Device identification objects
Device indentification objects in this appendix can be used only for transmitters, using unit ID
240.
Appendix A – Modbus reference
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