analog conversion/ output fail

[dshall]

New to programming, please excuse what I'm sure is a long and stupid question:

I'm building a training workstation with a CompactLogix. I have an AI card (1769-IF8) and an AO (1769-OF8C), both configured to 4-20mA. I'm trying to build a simple test program that takes the 4-20mA values on the input and MOVs them to the output (which has a mA panel meter). The input seems to be working properly (although it only gives data in INT format, so I'm not sure how to convert that to mA to know if it's accurate), but the output doesn't show up on the panel meter.
I checked the wiring, I used my process meter to source 4-20mA to check the panel meter. I also tried putting different numbers in a MOV to the output.

Help would be greatly appreciated, there's no one at my company to ask.

 

[gclshortt]

Are you sure you are looking at the correct channel? Is the selection switch on the card set to internal or external power.

http://literature.rockwellautomation.com/idc/groups/literature/documents/in/1769-in065_-en-p.pdf

I would disconnect the panel meter. Configure the output for voltage and measure it with a multimeter. Once you know it is working, switch back to 4-20 ma to the panel meter.

You need to scale the value using some math instructions in the plc.
For a quick tutorial on numbering systems check this out:
http://accautomation.ca/what-everyb...grammable-logic-controller-numbering-systems/

Regards,
Garry
http://www.accautomation.ca

 

[dshall]

Okay, looked over these:
Channel confirmed (Ch0)
Selection switch confirmed
Only output options on the card are 0-20mA & 4-20mA. I can read mA with my meter, but don't seem to be reading any off the output card so far.
I looked at the tutorial you linked to, but didn't see how to use it here:
My best guess is that part of the problem is that both input and output cards have INT as the only option for data type, and the ControlLogix cards I first trained on use either FLOAT or REAL.

 

[Ron Beaufort]

can you post your ACD program file? ... you'll have to zip it first - forum rule ...

takes the 4-20mA values on the input and MOVs them to the output

quick guess ... you have the MOV rung in a new subroutine file - and you didn't do a JSR (etc.) to tell the processor to scan/execute the new logic ...

 

[dshall]

There aren't any subroutines in the program.
Er, feeling very silly now, but I can't figure out how to attach files to this thread. Also, my laptop doesn't have winzip or anything. Is saving it as a .l5k acceptable?

 

[Ron Beaufort]

you can change its name (extension) from ACD to ZIP ... we can change it back to ACD and open it ...

how about a new Program - and you didn't set up a "Main Routine" for it? ...

.

 

[Mickey]

Zip programs are free..see link

http://download.cnet.com/7-Zip/3000-2250_4-10045185.html

 

[dshall]

File size is too big to attach as an ACD (3.2 MB). I made the .l5k into a zip, you should be able to change it back and import.

I wrote the program in the Main Routine. It was only 17 rungs that was simply to test the inputs and outputs of the training station, so I didn't want any unnecessary moving parts.

 

[Ron Beaufort]

see if this helps ...

.

 

[dshall]

That seems to have done it, Mr. Beaufort. Many thanks.

 

[Ron Beaufort]

you can play around with the other ranges (if you want to) now that you've got it working ...

just for more fun, consider hooking up an OUTPUT channel - and using it to feed an INPUT channel ...

 

[dshall]

Oh yes, a lot of fun to be had, now that it's running right. Thanks again.

 

[Sherlock4me]

I scratched my head for a moment when I read the suggestion of feeding an in with the out. (I too recently programmed a short analog out test with a MOV) on my CPX imbedded IO unit. But since I learned the majority of RsLogix 5000 from here, I knew Ron B is like EF Hutton. Anyway, Very cool another light bulb on, now channel 1 out feeds channel 3 in and the the logic adds 2 mA and puts it out Ch 0.

Love this site.

Good thread for us beginners dshall and remember, there are no stupid questions, just stupid people asking questions. (just a joke where I am still a bit pumped from this latest learning experience that took up all my outputs and used both flukes. : )

Thanks all