CHAPTER 4: SETPOINTS INPUTS
869 MOTOR PROTECTION SYSTEM – INSTRUCTION MANUAL 4–83
VOLTAGE THRESHOLD /Slot F/G/H
Range: 17, 33, 84, 166 VDC
Default: 33 VDC
The setting determines the minimum voltage required to detect a closed Contact Input.
The value is selected according to the following criteria: 17 for 24 V sources, 33 for 48 V
sources, 84 for 110 to 125 V sources and 166 for 250 V sources.
FAST PATH:
For internal wetting set the Voltage Threshold to 17V.
FAST PATH:
When thresholds above 17V are selected, the internal +24V is disabled.
NAME
Range: Up to 13 alphanumeric characters
Default: CI 1
An alphanumeric name may be assigned to a Contact Input for diagnostic, setting, and
event recording purposes. The CI X ON (Logic 1) FlexLogic™ operand corresponds to
Contact Input “X” being closed, while CI X OFF corresponds to Contact Input “X” being
open.
DEBOUNCE TIME
Range: 0.0 to 16.0 ms in steps of 0.5 ms
Default: 10.0 ms
The Debounce Time defines the time required for the contact to overcome ‘contact
bouncing’ conditions. As this time differs for different contact types and manufacturers,
set it as a maximum contact debounce time (per manufacturer specifications) plus some
margin to ensure proper operation.
EVENTS
Range: Enabled, Disabled
Default: Enabled
For example, to use Contact Input ‘1’ as a status input from the breaker 52b contact, to
seal-in the trip relay and record it in the Event Records menu, make the following settings
changes:
CONTACT INPUT 1 NAME: "52b"
CONTACT INPUT 1 EVENTS: "Enabled"
FAST PATH:
The 52b contact is closed when the breaker is open and open when the breaker is closed.
A raw status is scanned for all Contact Inputs synchronously at the constant rate of one
protection pass (1/8 cycle) as shown in the figure below. The DC input voltage is compared
to a user-settable threshold. A new Contact Input state must be maintained for a user
settable debounce time in order for the relay to validate the new contact state. In the
figure below, the debounce time is set at 2.5 ms; thus the 3rd sample in a row validates the
change of state (mark no. 2 in the diagram). Once validated (debounced), the new state will
be declared and a FlexLogic™ operand will be asserted at the time of a new protection
pass. A time stamp of the first sample in the sequence that validates the new state is used
when logging the change of the Contact Input into the Event Recorder (mark no. 1 in the
diagram).
Protection and control elements, as well as FlexLogic™ equations and timers, are executed
ei
ght times in a power system cycle. The protection pass duration is controlled by the
frequency tracking mechanism. The FlexLogic™ operand reflecting the debounced state of
the contact is updated at the protection pass following the debounce (marked no. 2 on the
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