sutton
Guest
S
Dear all PLC experts,
I'm a fresh graduated junior electrical engineer now involved in a PLC project of an automation machine. I encountered few problems during program test.
I am using a Shilin PLC now. I tried to test my software by using the 24VDC service supply connecting to the input contacts. there was a short circuit that cause the communication cable and computer com port spoilt. The reason of short circuit is because the service supply accidentally touch the metal case of a 24V adapter. The controller was fine fortunately.
1. I could not understand why the front part of the cable and computer comm port spoilt while the end part of the cable and PLC were fine?
2. Testing using the 24V service supply to the input contacts to read the input and output lamps were very dangerous. Two case of damages to device already happened. Is there any better ways of testing the PLC in a safer way?
Please post advices. Thank you.
sutton
I'm a fresh graduated junior electrical engineer now involved in a PLC project of an automation machine. I encountered few problems during program test.
I am using a Shilin PLC now. I tried to test my software by using the 24VDC service supply connecting to the input contacts. there was a short circuit that cause the communication cable and computer com port spoilt. The reason of short circuit is because the service supply accidentally touch the metal case of a 24V adapter. The controller was fine fortunately.
1. I could not understand why the front part of the cable and computer comm port spoilt while the end part of the cable and PLC were fine?
2. Testing using the 24V service supply to the input contacts to read the input and output lamps were very dangerous. Two case of damages to device already happened. Is there any better ways of testing the PLC in a safer way?
Please post advices. Thank you.
sutton