Can I use Channel 1? (AO)

JoelAspinall · Dec 11, 2019

Hi All,

I am hoping someone could please advise on the following:

I currently have a 1771-OFE/B Analog Output Module in my PLC5 Program via Remote IO Scanner.

The Module currently works fine. However, in the module setup, it shows that "Channel 1" is used for Write Data Block.

My question is - are we limited to only 3 channels? (2,3,4) or is it possible to use Channel 1?

Many thanks in advance. Screenshots below.

Mickey · Dec 11, 2019

Yes you can use it.

The "Write Data Block" description is typed in by someone.

I will say N19:0-3 are the register(s) used to write data to control the value of the output.
In that sense the description is correct. I would normally write what the output is used for.

JoelAspinall · Dec 11, 2019

Mickey said:
Yes you can use it.

The "Write Data Block" description is typed in by someone.

I will say N19:0-3 are the register(s) used to write data to control the value of the output.
In that sense the description is correct. I would normally write what the output is used for.

Thank you very much for taking the time to reply. So even though N19:0 is used for the "Data File" parameter in the BTW Instruction in the second screenshot, it will still work as an analog output if I connect N19:0 to say the output of a PID Block?

OkiePC · Dec 11, 2019

I think that RSLogix 5 will create that address description "Write data block" if you allow the software to create the ladder logic for you (INSERT LADDER RUNGS) or if you use the I/O config wizard to identify the logic and the data file is not already commented.

I normally go back and change those address comments to something that better explains what they're wired to as well as the physical location of the analog output card. IIRC, if you edit the description from within that config wizard, you might run into a character limit that is different from what you'll see if you edit the description from the data table viewer or from the ladder editor.

JoelAspinall · Dec 11, 2019

OkiePC said:
I think that RSLogix 5 will create that address description if you allow the software to create the ladder logic for you or if you use the I/O config wizard to identify the logic and the data file is not already commented.

I normally go back and change those address comments to something that better explains what they're wired to as well as the physical location of the analog output card. IIRC, if you edit the description from within that config wizard, you might run into a character limit that is different from what you'll see if you edit the description from the data table viewer or from the ladder editor.

Thanks for the reply OkiePC! You are right that this description came from the auto-config. What I am worried about is N19:0 appears to be used as the "Data File" parameter in the BTW (Second Screenshot). Will I still be able to link N19:0 (Channel 1) to the Output of a PID Block if it's used in the BTW Data File Parameter?

OkiePC · Dec 11, 2019

JoelAspinall said:
Thanks for the reply OkiePC! You are right that this description came from the auto-config. What I am worried about is N19:0 appears to be used as the "Data File" parameter in the BTW (Second Screenshot). Will I still be able to link N19:0 (Channel 1) to the Output of a PID Block if it's used in the BTW Data File Parameter?

Yes, it is part of the data file. It's the part that is used to scale the analog output for the first channel of the card. That block of data used by the BTW instruction is 13 words long and the first 4 words are the output channel data.

Yes, you can certainly write data to those first 4 words with other ladder logic. I would be leery about writing to any of the remaining data block with ladder logic unless you study the books closely and know what you are doing.

The next 9 words are used for the channel type and scaling methods being used. At one time when I worked mostly with PLC-5, I had a worksheet with all the details for these cards right down to every last bit all formatted for importing into RSLogix5 so I could open up Excel and type in the "base address" and then click a macro button to create a csv file for the database import utility. I wish I had saved some of those tools from that previous job. It sure did make commenting all the obscurities of many different PLC-5 cards so much easier and more thorough.

JoelAspinall · Dec 11, 2019

OkiePC said:
Yes, it is part of the data file. It's the part that is used to scale the analog output for the first channel of the card. That block of data used by the BTW instruction is 13 words long and the first 4 words are the output channel data.

Yes, you can certainly write data to those first 4 words with other ladder logic. I would be leery about writing to any of the remaining data block with ladder logic unless you study the books closely and know what you are doing.

The next 9 words are used for the channel type and scaling methods being used. At one time when I worked mostly with PLC-5, I had a worksheet with all the details for these cards right down to every last bit all formatted for importing into RSLogix5 so I could open up Excel and type in the "base address" and then click a macro button to create a csv file for the database import utility. I wish I had saved some of those tools from that previous job. It sure did make commenting all the obscurities of many different PLC-5 cards so much easier and more thorough.

Thank you to yourself and everyone else who replied. I appreciate it! Cheers!

Can I use Channel 1? (AO)

JoelAspinall

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Mickey

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JoelAspinall

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OkiePC

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JoelAspinall

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OkiePC

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JoelAspinall

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