With the current PLC program:
1.Every time the motor turns off from the bottle blocking sensor number 2, the operator has to press the start switch again and this is clearly not what I wanted in the automatic mode.
2.When a bottle gets in front of the sensor number 2 and the valve is open, if the operator changes the selector switch state at the same time, all of a sudden the motor runs and the conveyor belt moves, while the valve is still open!
So let's review the program and find out what's wrong here.
In this lesson, I'm going to replace this three position selector switch with a two position switch and then revise the software such that there won't be any change in the way that the machine operates. This means that with the new two position selector switch, I will be able to change the machin...
The number of S7 counters you can use in your program depends on the model of the CPU you're using in your project. How can you find out how many S7 counters you can use or what happens if you enter an out of range address in the software? These are what you'll learn after watching this lesson.
When you're using counters in your PLC program, if the PLC goes into the stop mode or the power cuts off, you'll lose all of the counter values and these values cannot be restored after running the PLC again.
There are some programming tools and setups in the "STEP 7" that can be used to protec...
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