What Elk Variables are Triggers to the ISY Programs?

[PLCGuy]

It appears that a number of Elk conditions are clearly triggers for program IF statements. For example, the following seems to execute happily when there is a change in status in the Elk Zone 'Front Door'

 

If
    Elk Zone 'Front Door' is Violated

Then
    Blah Blah...

But changes in voltage in a zone do not seem to drive program execution. For example, the following never seems to run.

 

If
       Elk Zone 'Water Level' 'Voltage' is 2.0 Volts

Then
       $ElkVoltageX10  = 20

Test if the Elk Voltage is 2.0 Volts and if so, set $ElkVoltagex10 to 20 (i.e. ten times the voltage)

 

In fact, the zone voltage just doesn't seem to ever update unless I also execute a Set Elk Zone 'Water Level' Query Voltage command. But when it is run, the voltages do seems to be capable of being program triggers.

 

Is this correct? Are voltages from Elk Zones only read into the ISY when the Set Elk Zone Query Voltage command is initiated? And then once they are read into the ISY, they will act as triggers?

 

Any clarity on this point of ISY/Elk interfacing is greatly appreciated.

[apostolakisl]

You are correct, voltages are not triggers on their own. You need something else to trigger and then ISY checks the voltage. There is no data stream of Elk zone voltages, Elk must be queried. So you can trigger the program to run on a time schedule and it will query the voltage, but you can't use the voltage to initiate the program, unless you have something else forcing a query.