65-2640XL-04 M2A Transmitter Operator’s Manual
Chapter 8: RS-485 Modbus Output
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Calibration Outcome Codes:
1=Sensor Missing
2=Sensor Too Weak
3=Signal Too Strong
4=Not Enough Span
5=Negative Reading
6=Span Gas Value Is Not OK
7=Calculated Zero Is Too Low
8=Calculated Zero Is Too High
9=Zero Failure
10=Span Failure
11=Calibration Is Overscale
12=LEL Sensor Offset Is Too High
13=LEL Null Operation Failed
14=Operation Not Performed
Register 39
Register 39 is the auto-zero disable.
0=AutoZero Enabled
1=AutoZero Disabled
Register 40
Register 40 is the remote configuration register access level
0=None
1=Alarm Reset
Function Code 16: Write Registers
There are 21 registers in Function Code 16 that can be used to write to the M2A. This manual only
describes Register 16 because it can be used to reset an alarm condition. For a complete
description of Function Code 16, see “Appendix C: Function Code 16 Registers” on page 60.
Register 16
Register 16 performs the same function as the ENTER button on the M2A. It is useful for
remotely silencing alarms. With the M2A in an alarm condition, bit [0] can be used to silence it.
Table 12: Register 16, Button Function
NOTE:
Register 40 in Function Code 03, the remote configuration register, must be set to 1 in
order for Register 16 to work.
Bit
Value & Field
[0]
ENTER (used for “Alarm
Reset”)
0=Not Pressed
1=Pressed
