RSLogix "Generating Checksum" Problems...


Thread Starter

Niall Watson

Dear List

Has anyone experienced a problem with RSLogix 5 and processor checksum problems??

When saving a program online and / or going off-line, a message box appears with "Processor Generating Checksum etc." and options to retry / cancel etc.

Pressing retry continually over a period of an hour has no effect; pressing cancel requires a full upload next time you try and go online. Maybe
acceptable for a 5/15 with a traffic light application - not acceptable for a 5/80E filled up to the whiskers!

Also, another nice problem is the "Assemble Edits Failed" when online editing. Again a full upload is required, sometimes the edited rung is
scrambled or deleted.

Does anyone have any similar experience or tips?

Thanks in advance

Niall Watson

sysero: systems integration solutions

Niall Watson

Phone: 01283 743022
a subsidiary of BI Industries plc

Mubarik Mustafa

Most probably you are using a version of RSLogix5 earlier than release 3.22.00 as these are known issues and are listed in the release notes for 3.22.00 and later. This is what the release notes say about it (ref. Rockwell software Knowledgebase Technote ID R505;

"IMPORTANT ALL USERS! Following an online edit or project download the Enhanced PLC5 processor must generate the processor checksum. The checksum generation is performed as a background processor task. The calculation can take seconds or minutes to complete. If you perform a save during the checksum calculation it is likely that you will be forced to upload the processor project the next time you Go Online. RSLogix 5 r3.22.00 or later warns you of this possibility if the checksum is being generated when you attempt to save the project."

"IMPORTANT ALL USERS! When you accept an online edit in RSLogix 5 r3.22.00 the data associated with the rung is transmitted to the processor. The data sent to the processor may be out-of-date. When you begin an online edit RSLogix 5 caches the values associated with the rung you are editing. Upon acceptance of the online edit the cached data is sent to the processor. This may affect your application program in ways you did not anticipate. RSLogix 5 r3.02.00 did not transmit any of the data to your processor. This resulted in many of you experiencing problems with online editing. Earlier versions of RSLogix 5 operate as r3.22.00 does, RSLogix 5 r3.22.00 restores this earlier functionality."

The best option is to upgrade to a newer version of RSLogix5.


Michael R. Batchelor

Check the processor info and see how much free memory you have. I'll bet not very much. (Full up to the whiskers, huh?)

If you're below 40-50 words, find something you can get rid of, and make the changes offline instead of online. Almost certainly on a machine of that size, if you have a program that consumes the whole thing there are some files with holes in the word usage. Compact all that down and reduce the file sizes. If you've got any rungs afi'd delete them. (Hey, they clearly aren't doing anything, right.)