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Emach

Can't find that OTE or OTL

13 posts in this topic

I have a machine with a pump control loop that uses a bit to enable a poor man's PID loop based on a flow meter. My concern is I cannot find anywhere is the ladder logic or the HMI where this bit would be set! I have a creeping suspicion that the previous engineer put in the PID loop and never removed his test bit. Any suggestions on how I might locate where this bit would be set? I already reviewed all my OTL's, MOV's, and COP's. A find all on the bit and word doesn't reveal a OTE. Thanks, Emach Edited by Emach

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What PLC are you using? processor catalog number? If you can attach the PLC program for review

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Is there a HMI or SCADA system attached to this controller.

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Have you tried a cross-reference?

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I have a SLC 5/04. Yes, I have a Panelview 1000 and a 1746-SDN attached. There is also one of the AB RS232 to Ethernet/IP stand alone modules in the cabinet but it only provides data to our OPC server. We do not write to the PLC via the Ethernet/IP. The bit in question doesnt appear in the tag editor on the PV. I am currently digging through the device net scanner's M files to see if I can relate my missing bit to a status bit on the appropriate drive. I will look into the cross reference, thanks for the advice. -Ryan

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You may also need to search direct tags in the Panelview. Unfortunately, FactoryTalk doesn't have a cross-reference, so the only way to look for usage of direct tags is to do the following on EACH screen. Ctrl-A (select all) Ctrl-R (replace tags) Search through the top window, which is a list of all tags found on that page, including direct tags. Unfortunately, you still have to locate which object the tag is in once you find which screen it's on (if any), but at least you can figure out which screen(s) it's on!

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Jeremy, I am so behind the software eight ball, we still use Panel Builder 32 here....

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Then you should be good! The tag database and cross-reference in Panelbuilder 32 is (IMHO) much better than the (basically nonexistent) one in FactoryTalk ME. Go figure.

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I know is not usefull for this case but I just want to say AB have a tool for get a list of tag (direct and indirect in panelview plus. You should found it in Startmenu -> Rockwell Software -> FactoryTalk View -> Tools -> Application Documenter
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If you didn't found the bit in the HMI as JRoss says, you could look in the program if indirect adressing is used. Writted bit in indirect adressing doesn't appear in cross ref because program just don't know witch word will be written. Look at my screen shot, it seems no B3 is used but in reallity, I write something in. We are curious so please when you'll found the bit....Tell us! Wish I help...

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SLCMAN, Thanks! Didn't know that tool was available, and I will certainly make use of it in the future!

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Is this an XIO or XIC instruction on the rung in front of the PID instruction? While that is OK for a a PLC/5 or CLX, its a huge no-no on a SLC. The SLC PID must be on an unconditional rung or bad and usually undesirable things happen to the integral sum.

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One way to find indirect addressing: Use Find, but instead of the whole address, search for "B[" to find file level indirection applied to any binary files, and Find "B3:[" to find all word level indirection in file B3, and Find "B3:10/[" to find all bit level indirection used on word B3:10. Of course, leave out the quotation marks in the find field, and substitute the appropriate file type character, number, and element as per your situation. Paul Edited by OkiePC

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