Programmable Logic Controller (PLC) Questions and Answers

This PLC is being used to start and stop an electric motor, and also to shut it down automatically if any of three “shutdown” conditions occur:

• Excessive vibration
• Overcurrent (overload heater contact)
• High winding temperature

Motor Trip Logic using PLC Programming

The status of each shutdown contact is as follows:

• Vibration contact: closed when okay, opens when vibration becomes excessive
• Overload contact: closed when okay, opens when overloaded
• Temperature contact: open when okay, closes when hot

Draw a PLC ladder-logic program to start and stop this motor.

Be sure to make the program latching so that the operator does not have to hold the Start button to keep the motor running.

Answer :

Share Your Answer / Comments

Credits : by Tony R. Kuphaldt – under CC BY 1.0

For More PLC Questions : CLICK HERE

Similar Articles:

• PLC Electric Motor Interlocks
• PLC Programming Questions & Answers – 4
• PLC Program for Conditional Control Logic
• PLC Latching Function
• PLC Conveyor Motor Ladder Logic
• PLC Programming Questions & Answers – 5
• PLC Pump Permissive Interlocks
• Programmable Logic Controllers Multiple Choice Questions
• PLC Program for Latching and unlatching Circuit
• PLC Motor Control Ladder Logic Programming