Trip Circuit Supervision (74Tcs); Figure 5-5 Logic Diagram: Trip Circuit Supervision Feature (74Tcs) - Siemens 7SR23 DAD Manual

Chapter 1) 7SR23 DAD Description Of Operation
5.3

Trip Circuit Supervision (74TCS)

The relay provides 12 trip circuit supervision elements. All elements are identical in operation and independent
from each other allowing 12 trip circuits to be monitored.
One or more binary inputs can be mapped to 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 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 Circuit Supervision element (e.g. 74TCS-n) allows the
user to realise several alternative monitoring schemes – see 'Applications Guide'.
Figure 5-5 Logic Diagram: Trip Circuit Supervision Feature (74TCS)
©2013 Siemens Protection Devices Limited Chapter 1 Page 29 of 36