Operation Techniques
91
4.17.7 Setpoint Programming Techniques
This section describes setpoint programming practice in examples. It is
recommended to use a special form provided in
Appendix C
to plan setpoint
parameters prior the user changes them in the instrument. Refer to
Appendix B
(
Tables B-6, B-7
) for the entire list of available setpoint triggers and their
abbreviations.
Using Numeric Triggers with Hysteresis
Example 4-1
illustrates a simple usage of numeric triggers.
Suppose that the setpoint monitors high current over 1500 A, and a low power
factor, either lag or lead, under 0.85, on either phase. All conditions are combined
by
OR
operation. This means that when either value exceeds its predefined operate
limit, the setpoint is triggered, and a 3-second delay timer runs. If the measured
value remains away from the threshold for minimum of 3 seconds, the setpoint is
operated. Three actions are made on setpoint operation:
- relay #1 is activated (assume, to operate alarm)
- counter #2 is incremented to count the number of relay operations
- setpoint operation and two actions mentioned above are recorded in the event
log
Example 4-1 Sample Of Using Numeric Triggers With Hysteresis
Trigger Conditions
Conjunction
Trigger parameter
Condi-
tion
Operateli
mit
Releaseli
mit
Condition #1
OR
High current
≥
1500
1450
Condition #2
OR
Low PF Lag
≤
0.85
0.90
Condition #3
OR
Low PF Lead
≤
0.85
0.90
Condition #4
OR
None
Setpoint actions
Delays
Action type
Action target
Unit
Operate Release
Action #1
Operate relay
#1
1 s
3
5
Action #2
INC counter
#2
Action #3
Event logging
Operate
Action #4
None
