Functional Description
3-17
Hardware Jumper Inputs
The software monitors the status of the hardware jumper terminal block inputs in order to determine what
the required operations are for any given condition.
Program Enable
Software continuously reads this input to determine when the user may make changes to the settings. If
installed, the relay settings may be altered as described in earlier in this section. If the jumper is not
installed, changes at the front panel are locked out. A program enable is only required when programming
at the front panel. It is not required when programming using the communications link.
Fail-Safe Enable
Software reads this input continuously to determine if the output contact status needs to be toggled to
provide deenergized output contacts on a trip. If it is enabled, the relay implements the fail-safe feature.
Output Disable
Software reads this input during trip decision making operations. If the jumper is installed, all terminal trip
time delay counters are impaired and no trip decisions can be made until the jumper has been removed.
Trip Reset
Software reads this input during trip decision making operations. If the jumper is connected the following
occurs:
•
All output contacts are reset to the untripped condition (this depends on the fail-safe enable
feature)
•
All internal time delay counter and trip pending flags are cleared
•
The reason for the last trip is cleared
•
The front panel display returns to the ON condition.
NOTE
This reset condition persists until the jumper is removed, regardless of any existing trip
conditions sensed by the relay.
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