Appendix Bmodbus Reference - Vaisala CARBOCAP GMW90 Series User Manual

Appendix B _________________________________________________________ Modbus Reference
APPENDIX B
MODBUS REFERENCE
NOTE
NOTE
VAISALA ________________________________________________________________________ 97
This appendix describes the Modbus protocol implementation of the
GMW90 series digital transmitters.
For more information on Modbus protocol, refer to the Specification and
Implementation Guide for Modbus Over Serial Line.
Serial line settings such as baud rate are configured using DIP switches.
See section Configuration of Digital Output Models on page 21.
Table 43 Modbus Functions Supported by GMW90
Function Code
03 (0x03)
04 (0x04)
06 (0x06)
16 (0x10)
43 / 14 (0x2B / 0x0E)
Table 44 GMW90 Modbus Measurement Data Registers
Name Metric float Metric
integer
CO2 0001...0002 0257 (×1)
RH 0003...0004 0258 (×0.01) %RH
T 0005...0006 0259 (×0.01) °C
Td 0007...0008 0260 (×0.01) °C
Tdf 0009...0010 0261 (×0.01) °C
dTd 0011...0012 0262 (×0.01) °C
Tw 0013...0014 0263 (×0.01) °C
a 0015...0016 0264 (×0.01) g/m3
x 0017...0018 0265 (×0.01) g/kg
h 0019...0020 0266 (×0.01) kJ/kg
Values read from the integer registers must be multiplied with the
provided multiplier to get the actual value. All integer values are signed.
Name
Read Holding Registers
Read Input Register
Write Single Register
Write Multiple Registers
Read Device Identification
Metric Non-metric Non-metric
unit float integer
ppm 6401...6402 6657 (×1)
6403...0004 6658 (×0.01)
6405...0006 6659 (×0.01)
6407...0008 6660 (×0.01)
6409...0010 6661 (×0.01)
6411...0012 6662 (×0.01)
6413...0014 6663 (×0.01)
6415...0016 6664 (×0.01)
6417...0018 6665 (×0.01)
6419...0020 6666 (×0.01)
Non-metric
unit
ppm
%RH
°F
°F
°F
°F
°F
gr/ft3
gr/lb
btu/lb