INITIAL SFC STEP FUNCTION (INIT
STEP)
This function can be used to set up an operating phase
or step for a PLC or a device. The phase corresponds to the initial state of an
independent SFC chart. This initialisation takes priority over all the input
values of this function. It forces a status token in its step, i.e. forces the
associated STEP OUTPUT to ON and deletes the tokens present in the STEP
TRANSITION OUTPUT.
If there is no RESET-INIT function in the independent
SFC chart, the INIT STEP function is automatically initialised in the following
situations:
- start of a simulation session
- "Initialise and On" command on the M2 controller
- restart after a mains failure
Outside of this initialisation, the function behaves
like a simple step function, i.e.:
- If a status token is present at STEP INPUT 1 or STEP INPUT 2 it is
stored immediately in the function step, switching the STEP OUTPUT to ON.
- This token remains stored in the step until the TRANSITION input
changes to the ON state. In this case, the status token crosses the transition
and disappears from the step. The STEP OUTPUT is set to ON and the token is
then available on the STEP TRANSITION OUTPUT and can be stored in the step or
steps connected downstream of this output.
- If there is no status token present at either input (STEP INPUT 1 and
STEP INPUT 2) and if the step does not already contain a status token, the step
remains empty and the STEP OUTPUT is set to OFF.
The non-connected inputs are set to neutral values for
the function, i.e.:
- The non-connected TRANSITION is maintained in the OFF state:
transition blocked
- The non-connected STEP INPUT 1 or STEP INPUT 2 is maintained with no
token present in the step input.
Caution, there must be at least one INIT STEP function
per independent SFC chart; equally, there may be several.
Parameterisation box/Comments
tab
For more information about SFC charts and this function,
see: SFC chart help.
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