Hi,

I have a problem with the operation of the program. I cannot understand why a certain situation occurs. I'll start from the beginning. The machine is a hydraulic press, a PILZ programmable safety controller (probably insignificant information for the described problem) and PLC is CPU 1515. The entire program is called in OB35 with a frequency of 10 [ms]. The average execution time of OB35 is 8 [ms]. The following has happened several times already:

The initialization sequence written in Graph is performed only when starting the automatic cycle (transfer reference movements), i.e. in full automatic mode, it stops at the last step. In each step, using the "N" action, the bool variable is written to the global DB block adequately to the step in which it is located, i.e. if the sequence is in step 44, then the 'S44' variable from global DB is saved in this step using the "N" action. The problem is that when I come to the machine after being called by the production department, the sequence is in first step (emergency stop initializes the sequences), while in the global DB I see that the variable of the last step S99 (i.e. the one before stopping) is "true" and the same variable S1 is "true" (which is normal and correct). Of course, this affects the start of the machine, because the variable S99 ='true' set in the last step blocks the execution of this sequence again - and it is necessary (I will not describe why, because it is not the essence of the problem). Therefore, in this situation, I have to reset the s99 variable in the global DB block and only then it is possible to start the machine.

My question is how is it possible that the variable S99 is not set to "false" after exiting the step?

I will be grateful for your help.

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