What is First Scan Bit and How to create a tag?
This bit is activated every time the PLC switches to run mode, as the name suggests, the first scan bit. You don't need to create any tags for the first scan bit.
When we look at what we can use this bit for;
Where can you use the First Scan Bit?
In power controls, for example, it is understood that the plc is re-started and accordingly. The contactors in certain parts of the machine can be energized by managing these contractors with the help of the timer for a certain time from the first start of the plc by means of a timer triggered by the S: FC bit.
Or generally, in safety circuits, the safety reset can be allowed after a certain period of time after the machine is ready, and reset conditions can be connected to it by using a timer named power on.
Default parameters are assigned by move and copy commands triggered by the S: FC command in order to reset commonly used sequencers or to make machine parameters default.