ABB TPU2000 Technical Manual page 367

Figure 8 ladder constructs are as such:
01000 is a system reset contact which when energized resets the MSTR and counters.
00112 is a system start contact which when energized allows the MSTR to read network data over
Modbus Plus.
If the network MSTR is idle (coil 00102 is de-energized or at a state of 0) then the timer energizes for the
time indicated in Register 400140. Upon timeout, 00106 energizes and latches in 00107 which starts the
MSTR instruction. Coil 00107 will be reset (or unlatched) when the MSTR terminates operation normally
or through error. Upon reset, the MSTR instruction will not execute. The timer shall reset and when it
times out, the entire sequence shall begin again.
The UCTR instruction contained in this logic counts the amount of Modbus Plus errors encountered when
communicating to the relay. Its count is kept in Register 400169.
Additional ladder logic can be written to transfer different pointers to obtain additional information from the
DPU2000R. The data would have to be transferred to Registers 400100 to 400108. The logic is relatively
straightforward.
Conclusion
The ABB series of Protective relays have been designed and certified to operate seamlessly with Modicon
Programmable Logic Controllers. The Ladder Logic is straightforward and easily implemented. Metering data,
element status, fault/operation records, device settings, and other important and time-critical information is easily
obtained from the relay using a programmable logic controller with Modbus Plus capability.
Reference Text
DPU/DPU2000R Modbus/Modbus Plus Implementation and Protocol Guide, Revision 1.5, August 18, 1998. ABB
Company
INSTRUCTIONS – DPU2000R Distribution Protection Unit 1MRA587219-MIB (IB 7.11.1.7-4), REF 544, Issue B,
October 1997, ABB Company
MODICON LADDER LOGIC BLOCK LIBRARY USERS GUIDE 840 USE 101 00, Version 1.1, July 1995, AEG
Schneider Automation
MODICON MODSOFT Programmer Software User Guide, 840 USE 115 00, Version 1.1, June 1996, AEG
Schneider Automation
MODBUS PLUS and SUBSTATION AUTOMATION, 8000BR9606R 11/97, REV C, Groupe Schneider
TPU2000/2000R Modbus/Modbus Plus Automation Guide
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