Siemens Siprotec 7UM62 Manual page 272

Functions
Table 2-16 Condition Table for Binary Inputs, Depending on RTC and CB Position
No. Trip Contact
1 Open
2 Open or
closed
3 Closed
4 Open
Monitoring with
One Binary Input
256
Depending on the conditions of the trip contact and the circuit breaker, the binary
inputs are activated (logical condition "H" in Table 2-16), or not activated (logical
condition "L").
.
Circuit AuxCont 1
Breaker
CLOSED Closed
OPEN Open
Closed
CLOSED
CLOSED Closed
or OPEN
With this solution, it is impossible to distinguish between status 2 ("normal operation
with open CB LS" and "KR triggered with success". However, these two statuses are
normal statues and thus not critical. Status 4 is only theoretical and indicates a
hardware error. Even for healthy trip circuits the condition that both binary inputs are
not actuated ("L") is possible during a short transition period (trip contact is closed, but
the circuit breaker has not yet opened.) A continuous state of this condition is only
possible when the trip circuit has been interrupted, a short-circuit exists in the trip
circuit, a loss of battery voltage occurs, or malfunctions occur with the circuit breaker
mechanism.
The conditions of the two binary inputs are checked periodically. A check takes place
about every 600 ms. If three consecutive conditional checks detect an abnormality
(after 1.8 s), an annunciation is reported (see Figure 2-122). The repeated
measurements help to determine the delay of the alarm message and to avoid that an
alarm is output during short-time transition phases. When the fault in the trip circuit has
been cleared, the annunciation is automatically reset.
The binary input is connected according to Figure 2-124 in parallel with the associated
trip contact. The circuit breaker auxiliary contact AuxCont2 is connected in series with
a high-ohm resistor R.
The control voltage for the circuit breaker should be about two times the value of the
minimum voltage drop at the binary (U
activate a binary input is 19 V, a DC voltage supply of 38 V or higher is required.
AuxCont 2 BI 1 BI 2
Open H L
Closed L H
Open L L
Closed H H
> 2·U
St BImin
Dyn. Status Stat. Status
Normal operation with closed CB
Normal operation with open CB or
RTC has tripped with success
Transition/fault Fault
Theoretical status: Aux. contact
defective,
BI defective, wrong connection
). Since the minimum voltage to
7UM62 Manual
C53000-G1176-C149-3