Binary Outputs (Output Relays) - Siemens 7SR224 Description & Operation

(1) Description of Operation 7SR224
2.9 B O (O R )
INARY UTPUTS UTPUT ELAYS
Relays are fitted with 14, 22 or 30 binary outputs. All outputs are fully user configurable and can be
programmed to operate from any or all of the available functions.
The Power Supply module includes the relay basic I/O. The module includes six binary outputs each
fitted with 1 contact – providing in total 1 x normally closed (NC), 2 x change-over (CO) and 3 x
normally open (NO) contacts.
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'. Alternatively, outputs can be programmed as 'Pulsed' outputs. When operated, these
outputs will reset automatically after a delay of the minimum operating time.
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.
When the relay is withdrawn from the case all normally closed contacts will be open circuited. This
should be considered in the design of the control and protection circuitry.
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. The relay will then reset and attempt to interrupt trip coil current flowing through an
output contact. Where this level is above the break rating of the output contact an auxiliary relay with
heavy-duty contacts should be utilised.in the primary system
Notes on Hand Reset Outputs
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.
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