96
Operation Techniques
Example 4-8 Sample Of Repeated Condition-Gated Operations
Trigger conditions
Conjunction
Trigger parameter
Condi-
tion
Operate
limit
Release
limit
Condition #1
OR
Timer #1
Condition #2
AND
R-T total kW
≥
20200
20000
Condition #3
AND
Relay status
OFF
Setpoint actions
Delays
Action type
Action target
Unit
Operate Release
Action #1
Operate relay
#1
0.1 s
0
5
Manual Setpoint Operations
The next example shows how to manually override setpoint conditions to operate
relay output via communications (see
Example 4-9
).
Programmable event flag #1 connected as a trigger with an
OR
operation is used to
provide manual forced setpoint operation. Manual setting of event flag #1 to ON
will immediately (since no operate delay specified) operate the setpoint by overriding
other setpoint conditions. Clearing the event flag does not ensure that the setpoint
will be released if other operate conditions are still fulfilled.
Example 4-9 Sample Of Manual Relay Operations
Trigger conditions
Conjunction
Trigger parameter
Condi-
tion
Operate
limit
Release
limit
Condition #1
OR
R-T total kW
≥
20050
20000
Condition #2
OR
R-T total PF Lag
≤
0.75
0.80
Condition #3
OR
R-T total PF Lead
≤
0.75
0.80
Condition #4
OR
User event flag #1
ON
Setpoint actions
Delays
Action type
Action target
Unit
Operate Release
Action #1
Operate relay
#1
0.1 s
0
0
In the same example, supposing for condition #4, an
OR
operation is replaced by an
AND
operation, and the ON condition is reversed to OFF, manual clearing of event
flag #1 will force the setpoint to be released regardless of other setpoint conditions.
Manual setting of the event flag will have no effect if other operate conditions are
not fulfilled.
