Vaisala HMW90 - Manual (Page 105)

Appendix B _________________________________________________________ Modbus Reference
VAISALA _______________________________________________________________________ 103
APPENDIX B
MODBUS REFERENCE
This appendix describes the Modbus protocol implementation of the
HMW90 series digital transmitters.
NOTE If a register is not relevant for the transmitter model, it does not exist
("illegal data address" code is returned).
Function Codes
Conformance class 0 function codes are enough to access the
measurement data and configuration settings of HMW90. In addition,
some class 1 commands are also supported, giving better compatibility.
Device identification data can be read out only with the function code
dedicated for that purpose (43 / 14).
Table 39 Supported Function Codes
Function Code Name Notes
03 (0x03) Read Holding Registers Class 0
04 (0x04) Read Input Register Class 1
06 (0x06) Write Single Register Class 1
16 (0x10) Write Multiple Registers Class 0
43 / 14 (0x2B / 0x0E) Read Device Identification