Analog module on PLC5/20

Deer

Member
Join Date
Jun 2002
Posts
124
Hi PLC guys,
I have a PLC Allen Bradley with type PLC5/20, complete with analog (1771-IFE/C, 1771-OFE)and digital modules.
Using RSLogix5 software, I have try to upload data from PLC5.
When the software RSLogix5 going to offline mode (PLC5 still running),on the I/O configuration we don't find list the I/O that has installed on the chassis PLC5/20.
The problem is, I don't know how to defined or read addresing each channel on the analog modules (1771-IFE/C, 1771-OFE), since analog module doesn't use addressing mode (1 slot, 1/2, 2slot,).This addressing only for digital modules.(different with SLC500, when upload program use RSLogix500, we can get list of all I/O Configuration even digital or analog modules).
Does anybody has experience it?
 
Hard to follow your question. I may understand it. Now, how to explain?

One of the benefits of the PLC 5 series of processors over the SLC is that the I/O does not need to be configured according to the actual existing I/O for the program to be downloaded.

One of the drawbacks from this is that the I/O can not be determined from doing an upload and reading the I/O configuration-chassis table.

The chassis table does not even need to be configured for the application to run properly. It is up to the programmer to type this information in. The information is displayed for information purposes only, and I have rarely ever seen it filled out correctly.

Finding the discrete I/O is rather easy. You can look at the useage table for data files 0 and 1. Analog I/O is not as easy. Doing a search for all BTW and BTR and if you know what your looking for, you can determine the I/O.

It is usually always easiest to just look at the I/O in the chassis and pray that it is set up for single slot addressing. 1/2, 2, or 1 slot addressing is, I believe, set up by dip switches on the backplane.

You can usually figure out the addressing type by looking at the program, but it is not straight forward. Remember that the PLC 5 series is Octal. Also, the CPU is not counted as a slot, and the first slot where you can place I/O is slot 0.

Hope this helps
 
Right.

The way to find where the analog modules are referenced is to search for all BTR and BTW instructions.

When you find them, make a list for each Rack/Group/Module of the Control Block and Data File for the BTR and BTW (there should be two per Analog Module).

You will not be able to tell (necessarily) what kind of modulle is being BTR/BTW'd, just be the instructions (the message length may be a clue, though). For that, you'll have to actually look at the rack.

When you're done, you'll be able to know what kind of addressing the rack DIP switches are set to (single, double, or half-slot) addressing, since the Rack/Group/Module numbers in the BTW/BTR will be different depending on the scheme.

Armed with this info, you can then go to I/O CONFIGURATION, double click on the Chassis Type, enter the proper i/o module, double click on it, and enter the correct addresses. When you're done, make sure you say "Configuration Already Exists" when prompted, or you could cause problems.

Then, when you double click on the Setup Screen on the BTW/BTR blocks, you will be able to see the raw inputs, and at what addresses.
 
Okay guys, thanks alot for your guide.
Anyway, I already solved my problem and I can read all analog addressing with SEARCH all BTR and BTW , entry the analog module to the I/O configuration with RSLogix5 ,and finally I got all address for analog module.

Regards,

Deer
 

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