Slc 5/04

I put a strobe light on top of a panel to show when they had low air pressure. I tried to use three different outputs to fire this light when we had low pressure. All three outputs would show that they were made in the program and on the card but yet there was no voltage on the output with or without the light hooked up. You could force the outputs on and off but if you went to the data table you could not put a one or a zero in the table, it would come up with "data file protected".

The outputs were static protected. I went offline, to the output tree, right clicked and selected properties for the output file, de-selected the static protection and set to none, then uploaded. When I went online with it, the changes did not take affect, the output file was still static protected and would not allow for the output to be forcd on through the data table.

Does anyone have any suggestions on why these outputs would not work? Thanks a bunch, you guys are great!

Memory module,do you have one install? Loading its program when you go to run. Thus eliminating the changes you just made.
If so store the changes to the memory module.

Since the machine isn't running right now, I have to get to others that are down, but I'll get back to it ASAP to let you know. Thanks Mickey!

Back to the no output voltage problem. Tell us which output module you have. And double check the wiring. Do any of the other outputs on this card work?

It's a relay card..ac or dc. The other outputs have voltage when they're energized, but they are being used in the program. All the other outputs on that relay card that are not being used will not show voltage when I energize them. There is an isolated relay card and I made an attempt to use of the unused outputs on it, but got the same problem, so I'm thinking the protection is global, not local.

There is a selectable box for the memory module in the properties of the output file when selecting the type of protection for it. Perhaps I should try clicking on it? Thanks for the help, Mickey

My tour of duty is over and I'll be passing the info on to the other techs. I'll get back to you ASAP. Thanks.

No matter what kind of protection you have the program should still be able to control the outputs. You said in your first post that the card shows the output on. post the catalog number of the output card if you have it.

If you have a 8 point or 16 point output card you need to power both groups. See PDF below for wiring diagram.

Also, it may have been just a simple typo, but...you said that after you made a change in the program while offline you then "UPLOADED". You should have "DOWNLOADED". Uploading takes the program from the PLC and brings it to the computer, downloading sends the program from the computer to the PLC. I'll bet you already know this, but just making sure we're not missing something simple.

I'd be willing to bet its a wiring problem. If I read right, you said its an isolated output card, in which case it has a separate input (or common) terminal for every output terminal. So, you would have to power each "common" that you plan to use the output for. If the commons are in fact powered (verified with a meter) and the program shows the output is on (data file and light on the front of the output card both show it being energized) and you are absolutely sure that all of the wiring is correct...it may be time to try another output card. They can go bad and start acting screwy.

Since you said that the status light on the module illuminates, Craig will definitely win his bet that it's a either a wiring issue, or a bad module... :nodi:



-Eric

Eric Nelson said:

Since you said that the status light on the module illuminates, Craig will definitely win his bet that it's a either a wiring issue, or a bad module... :nodi:



-Eric

Click to expand...

Sorry! I must have missed that line!