Elster Instromet 2000 - Appendix 3 d Rosemount GCX Chromatograph

Model 2000 Flow Computer Instruction Manual
APPENDIX 3 GAS CHROMATOGRAPHS SUPPORTED
Model 2000 issue 21 Page No
80
APPENDIX 3d Rosemount GCX Chromatograph
Gas Component Default Address Number Format
Status 10001 0 = OK 1 = Reset
Status 10002 0 = Run 1 = Stopped
Status 10003 to 10008 Ignored
Status 10009 to 100012 Ignored
Status 10013 1 = Sample flowing
Status 10014 1 = Flame Lit
Status 10015 to 10016 Ignored
Unit will continue to read the above status bit registers until the following conditions are correct
10001 = 0 i.e. OK
10002 = 0 i.e. Run
10013 = 1 i.e. Sample flowing
10014 = 1 i.e. Flame Lit
When these conditions are met it will continue to read addresses 30001 to 30020
Gas Component Default Address Number Format
Nitrogen N2 30001 unsigned 16 bit integer
Carbon Dioxide CO2 30003 unsigned 16 bit integer
Rel dens 30019 unsigned 16 bit integer
Superior Heating Value Hs 30015 unsigned 16 bit integer
Inferior Heating Value Hi 30016 unsigned 16 bit integer
Methane C1 30002 unsigned 16 bit integer
Ethane C2 30004 unsigned 16 bit integer
Propane C3 30005 unsigned 16 bit integer
i-Butane i-C4 30006 unsigned 16 bit integer
n-Butane n-C4 30007 unsigned 16 bit integer
i-Pentane i-C5 30009 unsigned 16 bit integer
n-Pentane n-C5 30010 unsigned 16 bit integer
C6+ 30011 unsigned 16 bit integer
Wobbe (superior) 30020 unsigned 16 bit integer
The Rosemount GCX interface supports the Following Modbus commands only
1) Read requests of Data Registers
[T1-T2-T3-T4]KK04ssssnnnn<CRC>[T1-T2-T3-T4]
2) Read requests of Status Registers
[T1-T2-T3-T4]KK02ssssnnnn<CRC>[T1-T2-T3-T4]
The Expected responses to the above packets from the GC are as follows:-
1) Valid Data Read Requests:
[T1-T2-T3-T4]KK04bb<DATA><CRC>[T1-T2-T3-T4]
2) Valid Status Read Requests:
[T1-T2-T3-T4]KK02bb<DATA><CRC>[T1-T2-T3-T4]
Where:
a) [T1-T2-T3-T4] is at least 3.5 character times of silent interval.
b) KK is the identification number.
c) 04 hex is the Modbus code "Read Analogue Registers".
d) 02 hex is the Modbus code "Read Digital Inputs".
e) ssss is the start address in the range 0000 to FFFF (0 to 63535 decimal).
f) nnnn number of registers in the range 0001 to 00FF (1 to 255 decimal).
g) bb is the number of bytes to be transferred.
h) <DATA> data nnnn items.
i) <CRC> CRC Checksum.