Write a PLC program so that if the start PB is pressed both conveyors run.
 The first conveyor stops in the presence of a bottle, and the second conveyor stops in the presence of the carton.
When the carton is present in front of the photocell 2 the first conveyor runs till the number of bottles in the carton reaches 5.
After that, the conveyor 2 should runs.
The first conveyor keeps running till the presence of the first bottle to come and stops waiting for the full carton to be moved away and the new carton presents.
When the empty new carton presents the conveyor 1 runs and counting the 5 bottles, and so on until the stop PB is pressed.
Note the best practice to learn the PLC programming is to start writing the PLC program, take your time before you review the answer.
Automatic Packing of Bottles
 Inputs & outputs
I0.0: Start Push Button (Normally open contact)
I0.1: Stop Push Button (Normally Closed Contact)
I0.2: photocell 01 (the photocell installed in the first conveyor).
I0.3: Photocell 02 (the photocell installed in the second conveyor).
Q0.0: conveyor 01.
Q0.1: Conveyor 02.
C1: Counter.
MW10: counter current value.
M0.0: start stop memory.
M1.0: carton full.
PLC Programming
Network 01
When the Start PB has pressed the set coil of the SR flip flop is energized and the start-stop memory bit is on.
If the stop PB is pressed the reset coil of the SR flip flop is energized and the start-stop memory bit is off.
Network 02
When the start-stop memory bit positive edge is detected or when the carton box is full, the set bit in the SR flip flop is energized and runs conveyor 02.
When the stop PB is pressed or the positive edge of photocell 2 is energized the conveyor 02 is stopped.
Network 03
When the start-stop bit is on or the positive edge of photocell 02 is detected the set bit is energized and runs conveyor 01.
When the stop button is pressed or when the positive edge of the photocell 1 is detected in case of there is no carton in front of photocell 2 or in case of the carton box is full, the reset bit of the SR flip flop should be energized.
Network 04
Photocell 01 increment the count in the counter C01 by one in case of the carton is not full. To avoid the counting of bottles in case that the carton is fully packed and did not move away from photocell 02.
The stop PB or the negative edge of the photocell 02 reset the counter’s counts to zero, to make sure when the full carton moves away from the photocell 02 the counter is reset to 0.
The counter’s counts are moved to MW10 counts memory.
When the count’s memory MW10 is equal to 5 the carton full bit is energized.
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