Loss of Analog input

I have had a good analog input/ 0-10v on a SLC 505 rack and analog card. However, I recently powered down the 10 card rack to insert a DC input card. After powering back up, I read the new I/O configuration and cleared the configuration fault.

The problem came when I switched to RUN, I no longer had a RAW count coming in on my only analog input (I:4.0). 6.24 volts is there, but no raw count. Cant seem to figure this one out. Help.

Did you move the analog card during the install of the digital I/O module?

no, I did think about it. I like to keep my low voltage cards away from my 120v cards. I might have slid it out while it was powered down, but none the less, the analog input card stayed in slot 4.

Several things come to mind.

1. you moved the card - you said no.
2. you had another analog card next to it and they got swapped.
3. in your program, do you write the initialization information to the card at power up and when you switch from program mode to run?
4. Is the initialization data for the analog card valid?
5. do a program compare against a backup before the changes were made and see what you get.

regards,
james

I've switched back and forth from program to run quite often and never had to re-initialize the analog card input.

I always clear errors before any downloads. The only thing I know for sure is that the analog input worked fine before adding the DC Input card in slot 9. Nothing since.

I've tried to re-initialize. It is a class 3 card, so it does it by itself. At least, the first time it did.

Post your program (the one that's in the PLC now). Its .RSS file ( zip it first)

Have you tried replacing the analog card with a new one?
card may have gone bad.

Have you checked to see if the card is inserted correctly and all the way in?
Maybe the power supply has failed or needs reseating to the chassis.

james

I am still learning a few things with PLCs. I watched RS Logix punch in its own instructions to initialize this output... something I didn't know RS Logix could even do. It was a class 3 card.

So, when I went into the program an hour ago, I wasn't surprised to see the rung that RS Logix put in on its own.... took out on its own.

I put the initializing S:1/15 bit and the COP instruction back in and the analog input 4.0 came back to life.

Still at a loss as to how and why RS Logix did this? I MAY have slid card 4 out during the addition of slot 9, but it was powered down. Could RS Logix "dump" its initializing instructions over THAT?!?!

Thanks

Still at a loss as to how and why RS Logix did this? I MAY have slid card 4 out during the addition of slot 9, but it was powered down. Could RS Logix "dump" its initializing instructions over THAT?!?!

Click to expand...

Is there a memory module installed. If so make sure it has the latest program in it.

I'm pretty sure there isn't. But I am gonna talk to management and recommend a memory module so we don't have to bother with batteries every two years. Thanks for your help.