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rdarling3599

How to correct Analog I/O config problems in PLC5

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Have a PLC5 project with remote racks with digital and analog I/O. For test purposes have wired AO to AI and have set up the BTW and BTRs. Problem is I put a value in the N11 register for the particular AO (N11:66 - BTW) and it doesn't appear in the other N11 register for the particular AI it is wired to (N11:4 - BTR). The AI - N11:4 continues to read a value of "8259" in decimal/"2042" in BCD, despite any value I put in the AO N11 register. The range of the AO is 4-20 mA with a Raw min of -4095 and a Raw max of 4095 and the range of the corresponding AI is 1-5VDC/4-20 mA. If I remove the wiring arm of the AI, the N11 register will read "4135" decimal. Would appreciate any fdbk as need to get working as system for customer will not be migrated to newer RA or Siemens system til next year. Cant get support out of AB for questions as only have standard "tech connect" tech support contract and PLC5 requires you to have "Legacy automation" tech support added to your "tech connect" stnd contract.

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post your ENTIRE project file (RSP) ... we'll see what we can do ... IMPORTANT: you also need to tell us the exact catalog numbers that you're using ... example: 1771-IFE/C and 1771-OFE2/B ... also, are you aware that there are JUMPERS inside most of the PLC-5 analog input modules? ... those need to be set up correctly ... also, are you aware of the differences between DIFFERENTIAL and SINGLE-ENDED wiring methods? ...which of those are you using? ... basic idea: the programming is only one piece of the puzzle - we can help you with that piece IF you'll post the RSP file ... BUT ... there is a LOT more that goes into getting this type of system to work correctly than just the programming ...we can't see those details by looking through the code - so you'll have to fill in the blanks if the programming doesn't solve your problems ... Edited by Ron Beaufort

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Ron is spot-on with PLC-5 in that the BTW and BTR block commands setup the module, but module dip switches (and if you are using single-slot or double-slot addressing) finish off the cake. Sometimes resurrecting old hardware for a test stand can require a tremendous amount of work.

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Thanks guys. They are 1771-OFE2/B for the AOs and 1771-IFE/C. Didn't see any dipswitches on the OFE and the IFE. The 1771-IFE is set for differential as that is how the AOs are wired to the AIs (i.e. 2 OFEs for every IFE). RSP file is attached - haven't put the code in it yet as wanted to get all the base I/O and RIO and ENet working first - this is the last thing I have to fix prior to putting the code in. Would appreciate any guidance. Thank you MME_PLC5_r1.zip

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I can't seem to post attachments - or even text from Microsoft Word - in this forum anymore ... try this link ... http://www.plctalk.net/qanda/showthread.php?p=667576&postcount=1 Edited by Ron Beaufort

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Here... Click on image to enlarge.(a little) Edited by Mickey

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Thanks a lot as this will allow me I hope to get the code in and working over Thanksgiving! I missed the range min on the OFE2. After I made the change to that but left them both at BCD, it didnt show the value in the IFE N register correctly when I pushed a value in the N register of the OFE but when I changed it to two's compliment binary, the numbers matched.

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