7SR18 Description Of Operation
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Notes on Self Reset Outputs
Self reset operation has a minimum reset time of 100 ms
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.
Notes on General Pickup
An output, General Pickup, is available to indicate that the pickup level has been exceeded for one or more
protection functions. Any protection function can be mapped to trigger this output in the OUTPUT
CONFIG>PICKUP CONFIG menu.
Figure 2.9-1 Binary Output Logic
2.10 Virtual Input/Output Connections
The relays have 8 virtual input/output connections, these are internal binary stores. By assigning the status of
data items like starters, alarms, equations etc. to a virtual input/output, the status of these items can be used to
fulfil higher levels of functionality.
The status of various data items can be assigned to virtual inputs/outputs using the INPUT CONFIG > OUTPUT
MATRIX menu.
These virtual input/outputs can be used as inputs to various functions - including blocks, inhibits, triggers, alarms
etc. - using the INPUT CONFIG > INPUT MATRIX menu.
Virtual input/outputs can also be used as data items in equations.
The status of the virtual inputs and outputs is volatile i.e. not stored during power loss.
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