RKI Instruments M2A - Manual (Page 62)

57 M2A Transmitter Operator’s Manual
Supported Modbus Functions
The M2A supports Function Code 03: Read Holding Registers and Function Code 16: Write
Registers.
Function Code 03: Read Holding Registers
There are a total of 40 registers available to be read via this Function Code.
Registers 1 - 2
The format (bit & field assignments) for registers 1 - 2 is shown below in Table 12 - Table 13.
Table 12: Register 1, Numerical Reading with Sign & Decimal Point Bit & Field Assignments
Bit(s) Value & Field
[15] Sign of Reading
0 = Positive
1 = Negative
[14:13] Format of Reading
0 = XXX (no decimal point)
1 = XX.X
2 = X.XX
3 = .XXX
[12:0] Numerical value of display reading (8000 max)
Table 13: Register 2, Operating State, Alarms & Relays Bit & Field Assignments
Bit(s) Value
[15:12] Operating State
0 = Undefined
1 = Initialization
2 = Normal
3 = Warm-up
4 = Fail
5 = Calibration
6 = Post-Calibration
7 = Low Power
8 = Setup
[11] Gas Type Change
0=Not Changed
1=Changed
[10] Configuration Change
0=Not Changed
1=Changed
[9] Calibration Activity Flag
0=No Calibration Activity
1=Calibration Activity Has Occurred
[8] Fail Status
0 = Fail Not Asserted
1 = Fail Asserted