Pneumercator MODBUS RTU RS-485 - TMS;LC2000 Data Register Map; MODBUS Status Register Detail

MODBUS RTU Instruction Manual - 2017-11-02.docx Page 8 of 14 November 2, 2017
2.1 TMS/LC2000 Data Register Map
Register Address Data Group
40001 MODBUS Status Re
g
iste
r
40002- 40017 Tank 1
40018- 40033 Tank 2
40034- 40049 Tank 3
40050- 40065 Tank 4
40066- 40081 Tank 5
40082- 40097 Tank 6
40098- 40113 Tank 7
40114- 40129 Tank 8
40130- 40145 Tank 9
40146- 40161 Tank 10
40162- 40177 Tank 11
40178- 40193 Tank 12
40194 Sensors 1- 4
40195 Sensors 5
–
8
40196 Sensors 9
–
12
40197 Sensors 13
–
16
40198 Sensors 17
–
20
40199 Sensors 21
–
24
40200 Sensors 25
–
28
40201 Sensors 29
–
32
40202 Sensors 33
–
36
40203 Sensors 37 - 40
40204 Contact Closure 1
–
4
40205 Contact Closure 5
–
8
40206 Contact Closure 9
–
12
40207 Contact Closure 13 - 16
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.