from the Addressing analog input department...
Addressing analog input cards in RS-logix 500
PLCs and related questions. topic
Posted by Steve on 8 February, 2003 - 12:00 pm
I am trying to find out how to address a 0-20ma tranducer to a AB input card. In RS-logix500

Posted by Les on 10 February, 2003 - 11:53 am
There's tons of free information on the Allen Bradley site at: <>

If your using a 1746-NI4 try this specifically.
Leslie or Joyce
Trouble-Les Computer Services
P.O. Box 423
Gustine, CA 95322 USA
PHONE (209) 854-1966
FAX (209) 854-1966
FAXWAVE (775) 659-0414

CA# SR DHF 99975947

Posted by Anthony Kerstens on 14 February, 2003 - 6:08 pm

In defense of Joe, I didn't detect anything pompous. If anything, there's a sense of being tired of the deluge of questions from amatuers. From "Welcome to, the global online community of automation professionals. Check out the technical articles
and participate in the technical discussions."

Read "technical discussions", not "technical support".

I don't mind students posing questions. I would however expect that they do their homework before they get to that point. If I don't get the sense that the student has done his homework, I simply delete the message.

If the person posing this question is not a student, then they really should go out and hire someone who knows what they are doing.

Anthony Kerstens P.Eng.

Posted by Anonymous on 10 February, 2003 - 12:03 pm
What type of AI card do you have? You have to do a BTR and set mbits and move the registers into an Nfile, You will need to know how many channels for the mbits.

Posted by PETERSONRA on 11 February, 2003 - 10:22 pm
> What type of AI card do you have? You have to do a BTR and set mbits and move the registers into an Nfile, You will need
> to know how many channels for the mbits.

Block transfer is only required if the card is located in a remote rack.

Keep in mind that some cards require configuration data be sent to the card.

For block transfers, use the BTW and BTR instructions. Much easier than the old way of doing block trnasfers if your CPU supports them. Some ancient ones do not.

Posted by Anonymous on 10 February, 2003 - 2:59 pm
Assuming you are using a SLC500 system, go here:

Posted by Charlie Mao on 10 February, 2003 - 5:16 pm
What analog input card did you use? NI8, NI16, NO4I or what?

Posted by Yosef Feigenbaum on 10 February, 2003 - 6:40 pm
I/O module addresses in the SLC-500 are designated by module type and module location. A module that requires more than 1 16 bit word of data table will have a '.' between the module location and the word number returned by the module. For example: 1746-NI4 (4 channel AI module) in slot #1 will return 4 words of data.

Channel 1 => I:1.0
Channel 2 => I:1.1
Channel 3 => I:1.2
Channel 4 => I:1.3

Some analog module return status data in addition to the channel data. A-B manuals are pretty good about explaining what data is returned (and is sent to) these modules.

Good luck,

(8{)} ( .)
Ludan Eng. LTD.

Posted by Chauvot on 11 February, 2003 - 9:31 am
It depends on what fieldbus you are using (i.e. Local, remote I/O, DeviceNet etc.). If local it will simply be I:card #.Channel #. For instance if you have 3 input cards and your interested in the 3rd channel of the second card it would be I:2.3. If using different fieldbus it would depend on your mapping.

Posted by Joe Jansen/TECH/HQ/KEMET/US on 11 February, 2003 - 2:19 pm
I am sure I will regret responding to this at all, but I felt the need.....

You're best bet would be to ask somone who has read any of the documentation, and is qualified to program the system. Seriously, unless this is for an academic situation, where no "real" equipment is being controlled, anyone that is asking this question is not qualified to be writing the controls.

If this is an acedemic situation, then you shouldn't get the answer here either. Do your homework and read the documentation. It is painfully simple to find and understand AB addressing for their "standard" modules. If you were asking about specialty modules that require complex data transfers through M0 and M1 files, that would be one thing, but addressing standard I/O modules is very well documented in the manuals, or the AB website.

BIG HINT: It maps like digital I/O, only doesn't use the bit level addressing, but instead stops at the word address. Each input is a seperate word, starting at 0.

Reminds me of a post about a magazine article recently.......

--Joe Jansen

Posted by Les on 13 February, 2003 - 12:37 pm
People are usually looking for help here, not pompous statements. A good thing to post would be a link to AB's doc site. like this.


Leslie or Joyce
Trouble-Les Computer Services
P.O. Box 423
Gustine, CA 95322 USA
PHONE (209) 854-1966
FAX (209) 854-1966
FAXWAVE (775) 659-0414

CA# SR DHF 99975947

Posted by Anonymous on 11 February, 2003 - 3:04 pm
If your input is on channel 0 of a card in slot one, it would be I:1.0

Go to and download a user manual for the module to see a programming example.

Posted by Ron on 12 February, 2003 - 12:07 pm
if you have the RSLogix500 software available, the easiest (and most instructive) way is to create a new program file - then go to I/O Configuration - set up the "virtual" I/O for your type chassis and then click and drag to "plug in" the type of analog card you want to use - then go to the input data table - you should see the input words corresponding to the slot you used - if you're using a 1746-NI4 (very common) there will be four words - one for each channel on the card - change the radix to decimal - the word addresses should be something along the lines of I:2.0 through I:2.3 - meaning input from slot 2 - channel 0 through channel 3 -

note: good news - there are no block transfers involved in analog signals for an SLC system - that stuff applies to the larger PLC-5 systems -

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