Note: Not all widgets might support the full
syntax as described in here. For those you can only
provide a PV name
Most widgets can react to ProcessVariables (PVs):
They usually display the current value of the PV as a
text, number or e.g. as a meter.
Even seemingly static elements like lines can change their
color based on the value of a PV.
EDM has the option of supporting several types of PVs.
When simply providing a PV name, the default type of PV
is used (usually EPICS). Otherwise, the type of PV is
selected via a prefix:
CALC\name(argA, argB, argC, ...)
The name of the PV, for example an EPICS channel name like
"fred" (served by excas, the Example ChannelAccess server)
or "sys_subsys:device:signal" for SNS names.
Forces "name" to be an EPICS channel name (might be the default).
Forces "name" to be a CALC PV.
Forces "name" to be of type XYZ (not implemented).
If you want to implement a new widget, please refer to
the header file edm/lib/pv_factory.h.