Satec PM172EH Series, Инструкция по установке и эксплуатации

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72 Appendix B Using Setpoints
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 PM172EH 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 PM172EH has 2 interval timers that can be programmed to generate
periodic events at user-defined intervals. They are commonly used for
periodic recording of interval data at the time of the fault or in the
presence of other events detected by setpoints.
Interval timers are not synchronized with the clock. When you run a timer,
it generates a pulsed timer 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 timer 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 in the
setpoint actions list a data log file you want to use for recording. If you
want the periodic data to be recorded in the 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.