Panametrics Aurora H2O, User Manual

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Aurora H2O User’s Manual 15
Appendix A. MODBUS RTU/TCP Communications
A.3 Modbus Registers (cont.)
1
Address 0 is the System Status register, and address 1000 is the latching version of the System Status register. That is,
both registers will show the error bit if the error is currently present, but only the latching register will show it if the
condition is no longer present. Writing 0 to the latching register will clear the error code it contains.
2
The
“
Trim Sequence Start/Resume Live Output
”
registers for the three outputs, (address 2100, 2200, 2300) accept
certain values through the Write Multiple Register to trim the output current:
1. Write 0 to 2x00 to select the normal mA output (proportional to measurement).
2. Write 1 to 2x00 to reset the mA output trim to factory defaults.
3. Write 2 to 2x00 to output the “zero” current (~4.000 mA) and accept a calibration value written to 2x40.
2. Write 3 to 2x00 to output the “span” current (~20.000 mA) and accept a calibration value written to 2x50.
Note: Attempting to write to Trim registers 2x40/2x50 without first writing to Trim State register 2x00 will fail with
Modbus exception 4.
At the end of calibration, write 0 to 2x00 to make Aurora H2O exit trim mode.