Hi,

SetBit and SetBitP are technological actions configured in the CmdStatLib. These technological actions can be used in EMT/EPHT to command CM/EM. You can right click and open the properties of the command to see what it does. If opened, you can see the window which is the same as in SFC. Each action has a Initialization/Processing and Termination tab. So when the action is executed, under the hood it executes Init/Processing/Termination. It depends how this is configured.

To tell you the difference-> SetBit sets a value in Initialization tab. SetBitP sets a value in Processing. 

As you may know already SFC works as follows: 

When a step is activated, all commands in Initialization are executed once, when the step is active, all commands in Processing is executed as long as the step is active. When the transition of the step is fulfilled and the next step is about to be entered, then the Termination commands are executed once. 

Hi edek,

To give you an example when to use SetBit or SetBitP:

When a step is active and the sequence goes to Holding->Hold and you resume the sequence and the sequence returns to the active step, then the Initialization tab is not executed because the step was already active. This is very important to know-> If you set a signal with SetBit when the step is activated, but in hold you need to reset the signal, then when the sequence returns to the step after hold, the signal will not be set anymore. In this case, you need to use SetBitP.

You can also change/delete/copy the existing commands and status. They are located in the CmdStatLib which is a hierarchy folder that Siemens provides with the SFC library where all commands are listed. Does not mean you cannot create your own command.