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7SR157 Technical Manual
Inverted Inputs
BI 1 inverted
Binary Input 1
INPUT
CONFIG>
BINARY
INPUT
CONFIG
BI n inverted
Binary Input n
2.8 Binary Outputs (Output Relays)
All outputs are fully user configurable and can be programmed to operate from any or all of the available
functions.
In the default mode of operation, binary outputs are self-reset and remain energised for a user-configurable
minimum time of up to 60 seconds. If required, outputs can be programmed to operate as 'hand-reset' or 'pulsed'.
If the output is programmed to be both 'hand-reset' and 'pulsed' then the output will default to 'hand-reset' only.
Operating a binary output as 'hand-reset' fulfils the requirements of ANSI function 86 (Lockout).
The binary outputs can be used to operate the trip coils of the circuit breaker directly where the trip coil current
does not exceed the 'make and carry' contact rating. The circuit breaker auxiliary contacts or other in-series
auxiliary device must be used to break the trip coil current.
Any BO can be assigned as a 'Trip Contact' in the OUTPUT CONFIG>TRIP CONFIG menu. Operation of a 'Trip
Contact' will operate any LED or virtual assigned from the 'Trip Triggered' feature in the same menu and will
initiate the fault record storage, actuate the 'Trip Alert' screen where enabled and CB Fail protection when
enabled.
Where a protection function is mapped to an output contact, the output contact can be configured to trigger when
the protection function picks-up rather than when it operates. Such output contacts are configured via the
OUTPUT CONFIG>BINARY OUTPUT CONFIG>Pickup Outputs setting.
Notes on Pulsed Outputs
When operated, the output will reset after a user configurable time of up to 60 seconds regardless of the initiating
condition.
Notes on Self Reset Outputs
Self reset operation has a minimum reset time of 100ms
With a failed breaker condition the relay may remain operated until current flow is interrupted by an upstream
device. When the current is removed the relay will then reset and attempt to interrupt trip coil current flowing via
its output contact. Where this current level is above the break rating of the output contact an auxiliary relay with
heavy-duty contacts should be utilised in the primary system to avoid damage to the relay.
Notes on Hand Reset Outputs – 86 Lockout
Any binary output can be programmed to provide an 86 lockout function by selecting it to be hand reset. Hand
reset outputs can be reset by either pressing the TEST/RESET► button, by energising a suitably programmed
binary input, or, by sending an appropriate command over the data communications channel(s).
On loss of the auxiliary supply hand-reset outputs will reset. When the auxiliary supply is re-established the binary
output will remain in the reset state unless the initiating condition is still present.
Chapter 1 - Page 16 of 38
BI 1 P/U Delay
=1
BI n P/U Delay
=1
Figure 2-9 Binary Input Logic
BI 1 D/O Delay
BI 1
Event
BI n D/O Delay
BI n
Event
© 2022 Siemens Protection Devices Limited
INPUT CONFIG>
INPUT MATRIX
(Or gates)
Logic signals
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