gbradley
Lifetime Supporting Member
Troubleshooting: It's time for me to share an embarasing story.
I had a machine that was not working. I assumed that the Solenoid valve had fried.
Ok I disconnected the Coil from the PLC output. It's a 110V coil coming from an old SLC100. I went back to the PLC and measured the voltage on the output, and it measured 107V. but the light wasn't on! How can this output be on?
I incorrectly assumed that when the coil went south, the output also went south.
Boy that was a bad assumption!
Well I had an old SLC100 laying around, so I actually changed out the PLC.
Then as soon as I measured the output voltage it hit me.
You have to have a load on this type of output contact in order for the potential difference to be measured.
Dog barking up the wrong tree.
I had a machine that was not working. I assumed that the Solenoid valve had fried.
Ok I disconnected the Coil from the PLC output. It's a 110V coil coming from an old SLC100. I went back to the PLC and measured the voltage on the output, and it measured 107V. but the light wasn't on! How can this output be on?
I incorrectly assumed that when the coil went south, the output also went south.
Boy that was a bad assumption!
Well I had an old SLC100 laying around, so I actually changed out the PLC.
Then as soon as I measured the output voltage it hit me.
You have to have a load on this type of output contact in order for the potential difference to be measured.
Dog barking up the wrong tree.