SATEC EM920 Operation Manual - Manual (Page 96)

Chapter 5 Configuring the EM920
General Meter Setup
96 EM920 Power Quality and Revenue Meter
Option Format/Range Description
Relation <=, >=, =, ON,
OFF The relational operator used in the conditional
expression for the trigger
Operate limit The threshold (in primary units) at which the
conditional expression would be evaluated to true.
Not applicable for digital triggers.
Release limit The threshold (in primary units) at which the
conditional expression would be evaluated to false.
Defines the hysteresis for analog triggers. Not
applicable for digital triggers.
Setpoint Actions
Action The action performed when the setpoint
expression is evaluated to true (see Appendix B)
Target The optional action target
Parameter The optional action argument (reserved)
Delays
Operate delay 0-10,000.000 s The time delay before operation when the operate
conditions are fulfilled
Release delay 0-10,000.000 s The time delay before release when the release
conditions are fulfilled
The logical controller provides very fast response to events.
The scan time for all setpoints is 1/2 cycle time (8 ms at
60Hz and 10 ms at 50 Hz).
Factory Preset Setpoints
Setpoint #1 is factory preset to provide standard
instrumentation data trending. It is linked to the meter clock
and triggers Data logs #1 and #2 on a 15-minute time basis.
Setpoint #16 is factory preset to provide energy load profile
recording to Data log #12 at 15-minute intervals. It is
protected from changes except of the time trigger operate
limit that you can set to any value from 1 to 60 minutes on
your selection.
Using Logical Expressions
Logical operators OR/AND are treated in a simplified manner.
They have no specific priority or precedence rules.
Any trigger condition bound to the logical expression by the
OR operator and evaluated as “true” overrides any preceding
condition evaluated as “false”. Similarly, any trigger condition
evaluated as “false” and bound by the AND operator
overrides any condition evaluated before it as “true”.
To avoid confusion, it is recommended not to alternate
different logical operators in one expression. Instead, bring
all conditions that use the same logical operator together at
one side of the expression, and the others - at the opposite
side.
To explicitly override all other conditions with the critical
trigger, put it at the end of the expression using the OR
operator if you want the setpoint to be operated anyway
when the trigger condition is asserted, and with the AND
operator, if the setpoint should not be operated while the
critical trigger is not asserted.