PLC Homework (revised 2018)
Due 4/12/2017
For 2018 class only do problem 2 and note underlined change.
#2)
A similar compressor has different shutdown requirements as listed below. It requires extra oil
pressure on startup that requires two lube oil pump on to start. After starting the compressor, the operator
has 30 seconds to turn off one of the pumps or the compressor shuts down. Given the following I/O
addressing, draw the gate logic diagram
and build in the on-line plc simulator software the
ladder logic
diagram to protect the compressor. Label all lines and contacts with the appropriate address.
Start Permissives
Lube pump #1 running
I/1
TRUE = Pump Running
Lube pump #2 running
I/2
TRUE = Pump Running
Start Signal
Start push button
I/0
Generate 30 second ON pulse to bypass Both oil pumps
running shutdown
Shutdowns
Loss of both oil pumps
I/1 & I/2
TRUE = Pump On
Both oil pumps running
I/1 & I/2
30 second delay on compressor start
Low lube oil pressure
I/3
TRUE = Oil Pressure Low
High lube oil temperature
I/4
TRUE = Oil Temperature High
Compressor Motor Contactor
O/0
**accidently left out the I/3 and I/4 that are on the second line after the exclusive or.
