GASMAX II Operation & Maintenance Manual, Revision 7.0
Page 47
9
MODBUS INTERFACE
The GASMAX II features a full complement of user-accessible MODBUS registers that can provide a
complete snapshot of each gas detectors configuration. This includes all real-time data, preset zero, span
and calibration values and user-programmable text.
Variable Name
Alias
Read
FC
Write
FC
Notes
Ch 1 Alarm 1
2001
2
N/A
Modbus Coils (read only)
Ch 1 Alarm 2
2002
2
N/A
Ch 1 Fault
2003
2
N/A
Ch 2 Alarm 1
2004
2
N/A
Ch 2 Alarm 2
2005
2
N/A
Ch 2 Fault
2006
2
N/A
K1 (Relay 1)
2007
2
N/A
K2 (Relay 2)
2008
2
N/A
K3 (Relay 3)
2009
2
N/A
Ch 1 Cal Mode
2010
2
N/A
Ch 2 Cal Mode
2011
2
N/A
Alarm ACK / Reset
12001
1
5
Write TRUE to ACK; resets to FALSE
Ch 1 D2A Raw
31001
4
N/A
10 bit value; 200 = 4mA, 1000 = 20mA
Ch 2 D2A Raw
31002
4
N/A
10 bit value; 200 = 4mA, 1000 = 20mA
Ch 1 A2D Raw
31003
4
N/A
10 bit value from A/D converter
Ch 2 A2D Raw
31004
4
N/A
10 bit value from A/D converter
Ch 1 Status
31005
4
N/A
See Channel Status Word definition
Ch 2 Status
31006
4
N/A
See Channel Status Word definition
Alarm Status Word
31007
4
N/A
See Alarm Status Word definition
Transmitter Status Word
31008
4
N/A
See Transmitter Status Word definition
Ch 1 Sensor Life
31009
4
N/A
16 bit signed integer ranging from -1 to
100 where -1 indicates Cal Required
Ch 2 Sensor Life
31010
4
N/A
16 bit signed integer ranging from -1 to
100 where -1 indicates Cal Required
Ch 1 Sensor Temp
31011
4
N/A
16 bit integer from 1 to 4095 scaled for
-55°C to +125°C
Ch 2 Sensor Temp
31012
4
N/A
16 bit integer from 1 to 4095 scaled for
-55°C to +125°C
Ch 1 Floating Point
33001
4
N/A
See Channel Floating Point definition
