Virtual Inputs - GE C70 Instruction Manual

INPUTS/OUTPUTS
Regardless of the contact debounce time setting, the contact input event is time-stamped with a 1 μs accuracy using the
time of the first scan corresponding to the new state (mark no. 2 shown). Therefore, the time stamp reflects a change in the
DC voltage across the contact input terminals that was not accidental as it was subsequently validated using the
debounce timer. Keep in mind that the associated FlexLogic operand is asserted/de-asserted later, after validating the
change.
The debounce algorithm is symmetrical: the same procedure and debounce time are used to filter the LOW-HIGH (marks
no.1, 2, 3, and 4 in the figure) and HIGH-LOW (marks no. 5, 6, 7, and 8) transitions.
Figure 5-137: Input contact debouncing mechanism and time-stamping sample timing
2
Time stamp of the first
scan corresponding to
the new validated state is
logged in the SOE record
5
SCAN TIME
(0.5 msec)
PROTECTION PASS
(8 times a cycle controlled by the
frequency tracking mechanism)
Contact inputs are isolated in groups of four to allow connection of wet contacts from different voltage sources for each
group. The
CONTACT INPUT THRESHOLDS
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.
For example, to use contact input H5a 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 H5a ID
CONTACT INPUT H5a EVENTS
Note that the 52b contact is closed when the breaker is open and open when the breaker is closed.

5.9.2 Virtual inputs

SETTINGS  INPUTS/OUTPUTS  VIRTUAL INPUTS  VIRTUAL INPUT 1(64)
 VIRTUAL INPUT 1

5-256
USER-PROGRAMMABLE THRESHOLD
1 3
At this time, the The FlexLogic
new (HIGH) operand is going to
contact state is be asserted at this
validated protection pass
DEBOUNCE TIME
(user setting)
4
TM
The FlexLogic operand
changes reflecting the
validated contact state
determine the minimum voltage required to detect a closed contact input. This
: "Breaker Closed (52b)"
: "Enabled"
VIRTUAL INPUT 1

FUNCTION: Disabled
VIRTUAL INPUT 1 ID:

Virt Ip 1
VIRTUAL INPUT 1

TYPE: Latched
C70 CAPACITOR BANK PROTECTION AND CONTROL SYSTEM – INSTRUCTION MANUAL
6
Time stamp of the first
TM
scan corresponding to the
new validated state is
logged in the SOE record
DEBOUNCE TIME
(user setting)
Range: Disabled, Enabled
Range: up to 12 alphanumeric characters
Range: Self-Reset, Latched
CHAPTER 5: SETTINGS
5
At this time, the new
(LOW) contact state is
validated
7
The FlexLogic TM
operand is going to be
de-asserted at this
protection pass
The FlexLogic TM operand
changes reflecting the
validated contact state
8
842709A1.cdr