Vaisala MMT330 - Manual (Page 167)

Appendix A _________________________________________________________ Modbus Reference
VAISALA _______________________________________________________________________ 167
Configuration Registers
Configuration parameter registers are used to configure the measurement.
Writing out-of-range values is silently ignored.
Table 37 Configuration Parameter Registers
Name Float Integer Valid Range
Pressure setting default
value 0769…0770 1025 (×1) 0…9999 hPa
Pressure setting
temporary value 0771…0772 1026 (×1) 0…9999 hPa
Oil-A 0777…0778 1029 (×0.01) ±99999.99
Oil-B 0779…0780 1030 (×0.0001) ±99.9999
If you modify the pressure setting repeatedly, modify the temporary
value at register 0771...0772 (1026) instead of the permanent setting at
register 0769…0770 (1025). Set the temporary value to zero to return to
the default pressure setting.
Non-metric units are not available on Modbus. If they are needed,
calculate the conversion outside the transmitter.
Configuration flags are used to select some basic options of the
instrument and to manually start the sensor operations.
Table 38 Configuration Flag Registers
Name Address Description
Standard filtering on/off 1281 1 = Filtering on
Extended filtering on/off 1282 1 = Extended filtering on
Flags 1281 and 1282 are mutually exclusive.
Some of the configuration registers might not have an effect depending
on the instrument model and configuration.
Other configuration settings are not usually needed and are not available
using the Modbus interface. The service cable must be used to change
other configuration settings if needed.
Exception Status Outputs
Exception status outputs (read with function code 07) tell the summary of
the MMT330 transmitter status as described in Table 39 below.
Table 39 MMT330 Exception Status Outputs
Output Name Description
0 (0x01) Fault status 1 = No errors
1 (0x02) Online status 1 = Online data available