Before diving into my problem I should explain, my employer has several TI-505 PLC's that control some of our operations. We did have a technician who programmed and maintained them but he is no longer here and has not been replaced. I normally install and maintain the mechanical parts of the system but it has fallen on me to keep the PLC's going as best as I can until a new PLC technician is hired, so forgive me if I ask some really basic questions.
Before he left, the technician did give me a one day crash course on keeping the 505's running, and up till now I've managed to solve every problem that has come up but I've run into a problem that I just can't figure out.
The Problem:
In one of our 505's we have a 505-4816 110v output board. One of the outputs goes to a relay. When the output is turned on and the relay is energized the relay occasionally momentarily de-energizes. There is no real pattern I can discern, it may be anywhere from 15 seconds to 3 minutes between the relay "clicks." The whole time the signal is on the relay just randomly clicks off then back on.
What I've tried:
My first thought was that it was probably a bad relay, so I replaced it, but that didn't solve the problem.
Next I thought maybe it was a problem with the 110v going to the 505-4816 board, so I rewired it and even tested it using a separate relay, and that didn't solve the problem.
So I thought it had to be the 505-4816 board. I had a spare board on hand so I swapped it out but that didn't solve the problem.
I read the ladder program in the 505, and as best as I can tell there isn't anything that would be momentarily turning off the output signal then turning it back on. It should be staying on until the operator manually opens a valve.
So I'm at a loss to figure out what is causing the relay to click off and on. Can anyone familiar with TI-505's offer advise on how to solve the problem?
Before he left, the technician did give me a one day crash course on keeping the 505's running, and up till now I've managed to solve every problem that has come up but I've run into a problem that I just can't figure out.
The Problem:
In one of our 505's we have a 505-4816 110v output board. One of the outputs goes to a relay. When the output is turned on and the relay is energized the relay occasionally momentarily de-energizes. There is no real pattern I can discern, it may be anywhere from 15 seconds to 3 minutes between the relay "clicks." The whole time the signal is on the relay just randomly clicks off then back on.
What I've tried:
My first thought was that it was probably a bad relay, so I replaced it, but that didn't solve the problem.
Next I thought maybe it was a problem with the 110v going to the 505-4816 board, so I rewired it and even tested it using a separate relay, and that didn't solve the problem.
So I thought it had to be the 505-4816 board. I had a spare board on hand so I swapped it out but that didn't solve the problem.
I read the ladder program in the 505, and as best as I can tell there isn't anything that would be momentarily turning off the output signal then turning it back on. It should be staying on until the operator manually opens a valve.
So I'm at a loss to figure out what is causing the relay to click off and on. Can anyone familiar with TI-505's offer advise on how to solve the problem?