Trip Circuit Supervision (74Tcs); Close Circuit Supervision (74Ccs); Figure 4-4 Logic Diagram: Trip Circuit Supervision Feature (74Tcs); Figure 4-5 Logic Diagram: Close Circuit Supervision Feature (74Ccs) - Siemens 7SR105 Rho User Manual

4.4

Trip Circuit Supervision (74TCS)

The relay provides three Trip Circuit Supervision elements.
One or more binary inputs can be mapped to Gn 74TCS-n. The inputs are connected into the trip circuit such that
at least one input is energised when the trip circuit wiring is intact. If all mapped inputs become de-energised, due
to a break in the trip circuit wiring or loss of supply an output is given.
The Gn 74TCS-n Delay setting prevents failure being incorrectly indicated during circuit breaker operation. This
delay should be greater than the operating time of the circuit breaker.
The use of one or two binary inputs mapped to the same Trip Circuit Supervision element (e.g. 74TCS-n) allows
the user to realise several alternative monitoring schemes – see 'Applications Guide'.
Gn 74TCS-n
Enabled
74TCS-n
74TCS-n
Figure 4-4
4.5

Close Circuit Supervision (74CCS)

The relay provides three Close Circuit Supervision elements.
Gn 74CCS-n
Enabled
74CCS-n
74CCS-n
Figure 4-5
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Element
≥
1
Logic Diagram: Trip Circuit Supervision Feature (74TCS)
Element
≥
1
Logic Diagram: Close Circuit Supervision Feature (74CCS)
Gn 74TCS-n Delay
&
NOTE: Diagram shows two binary inputs mapped
to the same Trip Circuit Supervision element
Gn 74CCS-n Delay
&
NOTE: Diagram shows two binary inputs mapped
to the same Close Circuit Supervision element
7SR105 Rho Description of Operation
TCS-n
CCS-n
Chapter 1 Page 41 of 57