ABB RELION 670 Series Technical Manual page 1334

Section 22
IED hardware
100k W
Soft ground
IEC07000242 V1 EN-US
Figure 667: Schematic view of soft ground
Grounding
At special problems with ground loops, the soft ground connection for the IIO-ground can be
tested.
Three different kinds of grounding principles can be set (used for fault tracing):
1. Direct ground - The normal grounding is direct ground, connect terminal 2 directly to the
chassis.
2. No ground - Leave the connector without any connection.
3. Soft ground - Connect soft ground pin (3), see figure
X.21 connector
Table 1041:Pinout for the X.21 communication connector
Pin number
1
2
3
4
6
8
9
10
11
13
5,7,12,14,15
22.2.16.3 Functionality
The data format is HDLC. The speed for the transmission of the messages used is 64 kbit/s.
1328
I/O
100nF
en07000242.vsd
Signal
Shield (ground)
TXD A
Control A
RXD A
Signal timing A
Ground
TXD B
Control B
RXD B
Signal timing B
Not used
666
GUID-4512904E-08D1-47EC-B005-E66170CEB130 v1
1MRK 502 066-UUS B
Technical manual