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ENCS

Accessing variables

Every project variable is available in a script as an object under its own name. A variable named OilTemp is therefore used directly:

temp = OilTemp.RawValue         # read the raw value
OilTemp.RawValue = 42           # write a value (the type converts automatically)
eng = OilTemp.EngValue          # the engineering value (after conversion), read-only
print(OilTemp.Name, OilTemp.Id) # the variable name and Id
  • RawValue — the raw value, read and write,
  • EngValue — the value after conversion (see Conversion and presentation), currently read-only,
  • Name, Id — the variable identification.

Shared script scope

All scripts of a project share one scope — whatever the Startup script prepares (functions, connections, counters) can be used by periodic scripts and cleaned up by the Shutdown script.

Reacting to a value change

A script in the OnValueChanged mode is bound to a specific variable. The trigger condition is tuned in Parameters:

source=eng;mode=above;threshold=50;hysteresis=2
  • source — evaluate the raw or the eng value,
  • mode — delta (change larger than the threshold), above/below (crossing a limit, with hysteresis),
  • threshold, hysteresis — the threshold and hysteresis.

A trigger can also be set conveniently right on the variable (the Variables section, On-change triggers → Add trigger):

An on-change trigger on a variableAn on-change trigger on a variable

When triggered, the engine passes context in the variables qenex_trigger_variable_name, qenex_trigger_old_value, qenex_trigger_new_value, and qenex_trigger_delta.

Next

The whole example put together — Example script.