Figure 4.11-1 Logic Diagram: Circuit Breaker Status - Siemens Argus 7SR21 Technical Manual

Blocked Close Delay
The close command may be delayed by a Block Close CB signal applied to a binary input. This causes the
feature to pause before it issues the CB close command and can be used, for example, to delay CB closure until
the CB energy has reached an acceptable level. If the Block signal has not been removed before the end of the
defined time, Blocked Close Delay, the relay will go to the lockout state.
Open CB Delay
The Open CB Delay setting is applicable to CB trip commands received through an Open CB binary input or via
the Control Menu. Operation of the Open CB binary output is delayed by the Open CB Delay setting.
NB: During the open countdown period the operation can be terminated by pressing 'Cancel' on the fascia.
Open CB Pulse
The duration of the CB open Command pulse is user settable to allow a range of CBs to be used.
CB Failed to Open is taken from the Circuit Breaker Failure Element.
CB Travel Alarm (DBI)
The CB Open and CB Closed binary inputs are continually monitored to track the CB Status.
The CB should only ever be in 3 states:
CB is Travelling between the above 2 states
The Relay goes to Lockout and the CB Alarm output is given where the Travelling condition exists for longer than
the CB Travel Alarm setting.
An instantaneous CB Alarm is given for a 1/1 state – i.e. where the CB indicates it is both Open and Closed at
the same time.
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CB Status
CB is Open
CB is Closed

Figure 4.11-1 Logic Diagram: Circuit Breaker Status

7SR210 & 7SR220 Description of Operation
CB Open CB Closed
binary input binary input
1
0
0
0
1
0
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