E-Mon E-PS-A-RTU-N - Manual (Page 74)

Chapter 4 Power
S O F T W A R E G E N E R A L M E T E R S E T U P
74 PowerSmart+ Advanced Power Quality Meter
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.
Using Numeric Triggers
For numeric (analog) triggers, a setpoint allows you to specify two thresholds for
each trigger to provide hysteresis (dead band) for setpoint operations. The Operate
Limit defines the operating threshold, and the second Release Limit defines the
release threshold for the trigger. The trigger thresholds are specified in primary
units.
If you do not want to use hysteresis for the trigger, set the Release Limit to the same
as the Operate Limit.
Using Binary Triggers
Binary (digital) triggers, like digital inputs, relays, or internal static and pulsed
events, are tested for ON (closed/set) or OFF (open/cleared) status.
The binary events are divided into two types: static events and pulsed events. Static
events are level-sensitive events. A static event is asserted all the time while the
corresponding condition exists. Examples are digital inputs, relays and event flags.
Pulsed events are edge-sensitive events with auto-reset. A pulsed event is
generated for a trigger only once when a positive transition edge is detected on the
trigger input. The examples of pulsed events are pulse inputs (transition pulses on
the digital inputs), internal pulsed events (energy pulses and time interval pulses),
and events generated by the interval timers. The logical controller automatically
clears pulsed events at the end of each scan, so that triggers that used pulsed
events are prevented from being triggered by the same event once again.
Using Event Flags
The PowerSmart+ Advanced PQM provides 8 common binary flags, called event
flags, which can be individually set, cleared and tested through setpoints and via
communications.
Event flags can be used in different applications, for example, to transfer events
between setpoints in order to expand a logical expression or a list of actions that
have to be done for a specific event, or to externally trigger setpoint actions from the
SCADA system or from a PLC through communications.
Using Interval Timers
The PowerSmart+ Advanced PQM provides four interval timers that are commonly
used for periodic recording of interval data at the time of the fault or in the presence
of other events detected by a setpoint. The timers can be programmed to generate
periodic events at user-defined intervals (see
Using Periodic Timers ).
Interval timers are not synchronized with the clock. When you run a timer, it
generates a pulsed event that can trigger a setpoint if you have put the timer into a
list of the setpoint triggers. When the setpoint event is asserted, the timer is
restarted, and then generates the next event when the timer interval expires.
If you want to record interval data at predefined intervals without linking to other
events, just select a timer as a setpoint trigger and specify a data log file you want to
use for recording, in the setpoint actions list. If you want the periodic data to be
recorded in presence of a specific event, select triggers that will identify your event,
and then add the timer at the end of the trigger list using the AND operator.
Using Time Triggers
If you want the setpoint actions to be synchronized with the clock, for example, to
provide synchronous recording interval data each 15 minutes or each hour, or to
output time pulses through relay contacts, use the time triggers that generate static
events synchronized to the device clock.