AB PLC5 Integer Maximum Elements Allowed

Good morning. I have a question regarding AB PLC5.

We have a AB PLC5 Processor (1785-L40E Rev B) in our plant with an existing running program on a running machine. I uploaded the current program and tried to download it to another AB PLC5 Processor (1785-L40E Rev D). But the downloading is unsuccessful. The error shows that N7 Integer file elements is more than 1000. Indeed I checked the uploaded program, the N7 Integer file elements is 1029.

I tried to change the N7 Integer file elements to 1000 as maximum on the uploaded program and it is able to download successfully. Then tried to go to program mode and changed the N7 Integer data element to 1029 but it won't allow me to do so.

I wonder how the existing running AB PLC5 (1785-L40E Rev B)processor was able to accept the existing N7 Integer File with 1029 elements.
What is the maximum allowable Integer file elements for a 1785-L40E Rev D processor? Is there any other way to configure the N7 Integer file of more 1000 elements that can be downloaded to a AB PLC5 Processor?

PLC-5 controllers have both a Series Letter and a Revision Letter.

The Series letter typically determines the physical hardware and the general capabilities of the controller. The Revision letter (sometimes a letter and a number, like "N.1") is only a firmware designation.

The PLC-5 controller operating system changed the limit on data elements per data file from 1000 to 2000 with the introduction of the Series E controller.

Thanks for the reply Ken. I forgot to mentioned that both the PLC5 processors that we have right now are Series E processors. Only the revisions are different.

While in offline mode, I can change the N7 integer file number of elements to more than 1000 elements but it does not successfully download to the 1785-L40E Series E controller.

Is it possible you are exceeding the available memory in the processor?

Can you post the .RSP file you are trying to download? Zip it first.

does not successfully download

Click to expand...

What error are you getting when the download fails?

There is a pop window showing the following details.

Download Failed!
Created Section Failed:Ext Sts - 0X01
Illegal Address
section=Data, file=7, length=1029

From my understanding this refers to data N7 Integer file which is currently configured with 1029 elements. Thus, when I changed it to 1000 elements then downloading will be fine without any error.

Memory size should also not an issue. There is still around 23K free memory out 49K memory for this processor.

Does your controller properties screen look like this?

Are you sure you have a series E Rev D controller?

Can you post the .RSP file you are trying to download?

Thanks for posting the specifics of that error message.

That suggests that it's the PLC-5 itself that is rejecting a data table definition being sent to it by RSLogix 5.

I've never heard of a Series E controller failing to support the expanded Series E data tables, but I suppose it's possible that there is a bug.

It's also possible that the controller isn't really running the firmware that's on the label, like if it was remanufactured and the wrong case or label was put on it (by RA or by somebody else). The Controller Properties window illustrated by Mickey in RSLogix or the RSLinx (right-click in the browse, select controller properties) should show you the exact firmware running in the controller.

It is almost the same as the image you posted except for the revision. It is showing B.

I got confused with Revision and F/W Revision.

My PLC processor details are as follows based on the sticker label at the side of the processor:

1785-L40E
Series E
F/W Revision B
Revision D01 (this is at the upper right corner of the sticker)

I am sorry, my company policy does not allow me to share the PLC program. If this hinders you to help me further, it is ok. Appreciate the replies and time you spent on this.

I don't have your controller, but when I try to change the element length to 1029 on a Rev B controller it will not let me, using RSLogix5. However it will with a Rev D.

I am not the expert when it comes to Rev's, but it appears that may be your problem.

Hopefully Ken checks back in.

I found the most detailed PLC-5 Release Notes knowledgebase document from this era (1997-1999). It's in the Knowledgebase, article 18946 (Access Level: Everyone).

Genery's experience is suggesting that a Series E Revision B controller supports data files over 1000 words, while a Series E Revision D controller does not.

That's not backed up by the release notes. Support for 2000 program files and 2000 data file elements was a major part of the first release of the Series E controller in 1997.

The only exceptions I read are a number of the less popular models that didn't get 2000 program file support until Series E Rev E. These were the PLC-5-11,26,30,86 controllers.

In 1999, the PLC-5/40E was by far the most popular model of PLC-5 controller.

It's possible there's a bug or difference that I'm not aware of or that's not documented in that list. I think only Rockwell Automation is going to be able to answer this question effectively.