ERRORS AND WARNINGS DETECTED ON AN SFC CHART
These errors and warnings can only appear:
These errors make themselves visible in the edit window by applying a red border to the group of SFC functions affected. Warning: These red borders disappear as soon as you click with the mouse in the Edit window. To restore the borders simply activate the Check program command for example.
If there are multiple errors (Error 60) or multiple warnings (Warning 70), it is recommended that each error and/or each warning is corrected in succession and that the "Check the program" command in the "Controller" menu is used, until a correct program is obtained.
ERROR 60:
An independent SFC chart has neither the RESETTABLE INITIAL SFC STEP nor the INITIAL SFC STEP function: it is not known which operating phase will be started (i.e. which step will be activated) when the user program is initialised prior to execution (initialise and on or simulation).
An independent SFC chart has several RESETTABLE INITIAL SFC STEP functions.
This warning is generated if several different types of warning are detected.
The wiring mode used to connect the function inputs and outputs does not permit one input to be connected to more than one output but does permit one output to be connected to more than one input of the same type. This property of course applies to the wiring of "status token circulation" inputs and outputs. However, this type of wiring is equivalent to the execution of a divergence to AND (DIVERGENCE TO AND WITH 2 SFC BRANCHES function) with several outputs. To emphasise this equivalence, the connections and functions affected are highlighted in red when the warning is activated.
In most cases, SFC charts depicting operating phases of a continuous PLC are looped back when all the "status token circulation" links are taken into account.
Therefore, it would be unusual to find an SFC function which did not have at least one output connected to an input of another function. This corresponds to a blocked operating phase in the event of the absence of program reinitialisation (which interrupts the blocked operating phase and activates the operating phase(s) associated with the INITIAL SFC STEP and RESETTABLE INITIAL SFC STEP functions of the SFC chart under consideration).
It would also be unusual to find an SFC function (other than an INITIAL SFC STEP or a RESETTABLE INITIAL SFC STEP) in a chart with no "status token circulation" type inputs connected to one input of the same type. This would correspond to a dead branch that would never be activated.
All affected symbols are highlighted in red.
Example: No "status token circulation" type inputs are wired on block B02 and the "status token circulation" type output on block B04 is not wired.