Pneumercator MODBUS RTU RS-485 Instruction Manual page 8

2.1 TMS/LC2000 Data Register Map
Register Address Data Group
40001
40002- 40017
40018- 40033
40034- 40049
40050- 40065
40066- 40081
40082- 40097
40098- 40113
40114- 40129
40130- 40145
40146- 40161
40162- 40177
40178- 40193
40194
40195
40196
40197
40198
40199
40200
40201
40202
40203
40204
40205
40206
40207
Note: Tank Registers 40002-40193 do not apply to the LC2000 since it does not interface with level probes.
2.1.1 MODBUS Status Register Detail
The least-significant bit (LSB) of the MODBUS Status Register (MSR) maintains the status of
communications between MODBUS and TMS/LC2000 processors. If for any reason communications
between these two processors is lost, the MODBUS processor will set the LSB of the MSR to "1".
Additionally, the MODBUS processor will force all tank data to full positive scale except ullage, which
will be forced to zero. If communications is normal, the MSR LSB will be set to "0". The second-
significant bit (2SB) of the MSR maintains the status of the TMS tank probe data acquisition process,
which is normally scanning tanks on a continuous basis, indicated by the 2SB set to "0". If an on-site
technician is in the process of altering TMS tank or probe configuration data via the TMS front panel,
tank data acquisition scanning will be suspended and the 2SB will be set to a "1". Scanning will resume
and the 2SB will set to "0" after the new settings have been saved.
The MSR should be checked occasionally since these statuses indicate that MODBUS register data is
not being updated. Typically, the entire MODBUS register set is updated every 0.8 to 1.2 seconds, and
the MSR communications status bit is set to "1" after 10 seconds of failed TMS/LC2000
communications. Note that although all unused bits in the MSR are set to zero, they may be used in
future firmware versions.
MODBUS RTU Instruction Manual - 2017-11-02.docx
MODBUS Status Register
Tank 1
Tank 2
Tank 3
Tank 4
Tank 5
Tank 6
Tank 7
Tank 8
Tank 9
Tank 10
Tank 11
Tank 12
Sensors 1- 4
Sensors 5 - 8
Sensors 9 - 12
Sensors 13 - 16
Sensors 17 - 20
Sensors 21 - 24
Sensors 25 - 28
Sensors 29 - 32
Sensors 33 - 36
Sensors 37 - 40
Contact Closure 1 - 4
Contact Closure 5 - 8
Contact Closure 9 - 12
Contact Closure 13 - 16
Page 8 of 14 November 2, 2017