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2 Functions
Figure 2-90
TR
CB
TC
Aux1
Aux2
U-CTR
U-BI1
U-BI2
Monitoring with two binary inputs not only detects interruptions in the trip circuit and
loss of control voltage, it also supervises the response of the circuit breaker using the
position of the circuit breaker auxiliary contacts.
Depending on the conditions of the trip contact and the circuit breaker, the binary
inputs are activated (logical condition „H" in the following table), or short-circuited (log-
ical condition „L").
A state in which both binary inputs are not activated („L") is only possible in intact trip
circuits for a short transition period (trip relay contact closed but circuit breaker not yet
open).
A continuous state of this condition is only possible when the trip circuit has been in-
terrupted, a short-circuit exists in the trip circuit, a loss of battery voltage occurs, or
malfunctions occur with the circuit breaker mechanism. Therefore, it is used as moni-
toring criterion.
Table 2-8
Condition table for binary inputs, depending on RTC and CB position
No.
Trip Contact
Circuit Breaker
1
Open
2
Open
3
Closed
4
Closed
216
Principle of the trip circuit supervision with two binary inputs
Trip relay contact
Circuit breaker
Circuit breaker trip coil
Circuit breaker auxiliary contact (NC contact)
Circuit breaker auxiliary contact (NO contact)
Control voltage (trip voltage)
Input voltage of 1st binary input
Input voltage of 2nd binary input
Aux 1
ON
Closed
OFF
Open
ON
Closed
OFF
Open
Aux 2
BI 1 BI 2
Dynamic State
Open
H
L
Closed
H
H
Open
L
L
Transition or mal-
Closed
L
H
Static State
Normal operation with circuit
breaker closed
Normal operation with circuit
breaker open
Malfunction
function
TR has tripped successfully
7SD610 Manual
C53000-G1176-C145-4
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