User`s guide

Appendix A _________________________________________________________ Modbus Reference
VAISALA _______________________________________________________________________ 175
Configuration Registers
Configuration parameter registers are used to configure the measurement.
Writing out-of-range values is silently ignored.
Table 38 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 39 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 40 below.
Table 40 MMT330 Exception Status Outputs
Output
Name
Description
0 (0x01)
Fault status
1 = No errors
1 (0x02)
Online status
1 = Online data available