ABB REL 356

ABB REL 356 Current Differential Protection
6-3
Computer Communications
Troubleshooting
In the event the communication remains unsuccessful, first make sure that the relay is powered, proper communication
cable is used (Table 6-1), and the connection is good.
For further testing, check that the bit rate (Baud) on the RS-PONI (Table 6-2) is set to correspond to the one displayed
at the bottom right of the RCP display.
If after these verifications the problem remains, try to remove the power from the relay and apply it again. If the
communication still fails (several attempts), the communication equipment needs to be serviced.
Sixteen Fault Target Data
The REL 356 saves the latest 16 fault records, but only the latest two fault records can be accessed from the front panel.
For complete 16 fault data, the computer communication is necessary.
Digital Fault Recording
Three digital fault records are stored in REL 356. Each set includes seven analog traces (Va, Vb , Vc , Ia , Ib , Ic and In),
with one cycle pre-fault and 7-cycle fault information, and 64 digital signals based on 12 samples per cycle.
NOTE: IF POWER IS INTERRUPTED TO RELAY ALL “OSCILLOGRAPHIC DATA” WILL BE LOST.
Table 6-1. Communications Cable Requirements
Connection Type
Cable
(Straight = no
null modem)
Pins Req'd
(All pins
not required)
Cable Connectors Data Rate
DB-25S, RS-232C connected to PC* Straight 2, 3, 7
To port: 25 pin DTE
To PC: 9 or 25 pin DCE
1200 bps only
DB-25S, RS-232C connected to modem Null Modem 2, 3, 7
To port: 25 pin DTE
to Modem: 25 pin DTE
1200 bps only
DB-9P, RS-232C connected to PC* Null Modem 2, 3, 5
To port: 9 pin DCE
To PC: 9 or 25 pin DCE
See Table 6-2
For settings
DB-9P, RS-232C connected to modem*
Straight
2, 3, 5
To port: 9 pin DCE
To Modem: 25 pin DTE
See Table 6-2
For settings