Allen Bradley Analog Input 1746-NI16I module

JoeN

Member
Join Date
Oct 2004
Posts
2
I am adding scale weight inputs (4-20MA) to a existing program, using analog input card (1746-NI16I- Class 3). Processor is 1747-L542C 5/04 CPU. I have been using the card for other 4-20 inputs, I have been unable to configure the additional channels to show the input. I set program up the same as others, using SLC blocks to scale the inputs and send them to panalview. I have been through the manual and setup with no success. I have went through the status word tables and tried changing bits to enable the additional channels, the bits change back to zero. I have also tried changing offline and downloading new congfig. with same result. I tried switching with another card, same result. I have the 4-20MA signal to the card, I checked with meter to verify signal and polarity. I keep thinking I am missing something simple, any suggestions?
 
you said:

the bits change back to zero

based on that, it sounds like some logic in your program is overwriting the new configuration values that you're entering ... I'd check for that ...

if you'll post your .RSS program file, we'll be glad to take a look and see if we can help spot anything suspicious ...

this post should help if you want to post your program ...
 
I just looked at an old program & I configured the configuration data table manually. I noticed in the newer version of RSLogix 500 that there is now a configuration wizard. So I tried setting up a new one off line & once you get over channel 8 (i.e. starting with 9) it will not let the channel remain enabled after clicking apply. The more troubling aspect is that it sets the WRONG bit in the configuration file that it automatically sets up.

I recommend reading the manual and setting up the config file manually. Also as Ron suggests post the file & we can help with the configuration logic.

Darren
 
image file

JoeN
you seid thae you are trying to change the bits in the status words and this is can't be done.you should configure your channels from the output image file for the card and as advised you should do it manually.
review the manual because there should be a bit for each channel in the output image file (32 word) which enable/disable the channel.
Good Luck
 
plc file

The analog inputs I am having trouble with are I:4.12,13,14,15 of the attached file. Thanks for the help.
 
Greetings Joe,

sorry that I don’t have time to go over your program in detail ... so I might have missed something ... but at this point, I don’t see anything obvious in your logic that could be overwriting the configuration bits as you reported in your first post ... is there a chance that the “overwrite” is coming in from something like the Panelview or Foxboro devices? ...

can you safely disconnect the communications from the Panelview and/or the Foxboro temporarily and try setting the configuration bits again? ... if the configuration values “stick” but then are overwritten once a device is plugged back in, then you should be able to track down the culprit ...

I’ll take a closer look as soon as I get a chance ... maybe someone else will spot it sooner ...

and a quick final thought ... are you (or are you not) typing the new configuration values right into the output data table as InControl just suggested? ... if you’re using the configuration feature, you might be running into the “bug” that Darren mentioned ...
 

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