A machine tool in a manufacturing cell is driven by the 3-phase a.c. motor controlled by the inverter. Before the inverter receives a RUN signal from a PLC, the given conditions should be met:

a) The work piece is to be in its initial position in chuck. (WPI)

b) The lubrication pressure is to be 5 bar or above. (LUB)

c) No movement is to have been noticed in the cell for 1 minute. (SAFE)

d) The pre-start inverter self-test routine is to be suitable. (TEST)

e) The motor should be stationary, that is, the motor speed signal is to be zero. (RPM0)

f) The manufacturing cell door is to be shut. (DOOR)

When the above conditions are met the PLC is to output a RUN signal to the inverter. The output is to be from a rung dedicated to the outputs. The memory element on this rung is to be activated through memory cell MC1.

The output rung is as well to control an output to the manufacturing cell door bolt solenoid.

Memory cell MC1 is to remain on till one of the given takes place:

a) Motor speed surpasses 1000 rpm. (RPM1000)
b) Emergency stop button is pressed. (EMER)
c) Lubrication pressure drops below 5 bar. (LUB)
d) A signal pointing out the end of machining is received. (END)

Whenever memory cell MC1 goes high, the given occur:

a) MC1 is to receive a hold in supply.
b) The inverter is to receive a RUN signal. (RUN)
c) The manufacturing cell door is to be locked through a solenoid-operated bolt. (LOCK)

Draw a ladder diagram to symbolize the software program which must be installed in the program memory of the PLC. Recognize the elements on the rungs by abbreviations.