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About TWControls

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    Industrial Sorcerer
  • Birthday 02/23/77

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  • Location Roanoke, Virginia
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  1. Subroutine

    If you had posted you program like we asked, we would have walked you through it.  I'd say all of us are around 90% certain of you are doing wrong, but without seeing your work it is hard to be sure how to guide you.  Vague questions will always lead to vague answers.  I'd consider editing your last post.  Most of these guys are going to less like to help you after they read it.
  2. Subroutine

    Why don't you post your program so we can have a look.
  3. Retrive Password from mer file

    No one here can help you bypass any type of password. It's against the terms of use of the website.
  4. Common folk

    Have you written out the steps it will take to do the sequence including inputs and outputs required for each step?
  5. Major Fault

    Thanks for letting us know what you found. I would recommend adding a ring of code so that that array index ends up being greater than the array size, it moves the safest possible value back into it and sets some alarm.
  6. Major Fault

    What is the size of the arrays used in your message instruction?
  7. Interview Question

    Here's a question for you. Are you looking for an employee that can troubleshoot PLC programs or the machines? 95% of the time there's nothing wrong with the program. The question usually is can he figure out why the motor isn't running. I think a better test would be a ladder program with numerous permissive to start a motor. Then the question be if the motor will not run what should you look at on the machine to determine why it's not running. Safety gates, e stops, limit switches, Etc
  8. To Infinity

    I didn't catch the decimal.  Probably switching the low tag to floating and lowering the trigger will work, but how many decimals to the left and the right will you need?
  9. To Infinity

    You are pretty much on the right track.  If it were me I would have two DINTs, LowDint and HighDint.  LowDint increments as normal, then have a GEQ source A being the LowDint and source B being 1,000,000,000 to add one to the to the HighDint and set the LowDint back to 0.  Then convert both to strings and Concatenate them into a string that represents the flow total.
  10. RS Logix 500

    I don't think it will have anything to do with the network switch since you data is coming over Devicenet.  If the data is coming over Devicenet then you Ethernet configuration isn't causing the problem, it is more  like it is helping expose the root problem.  See page 30 of the following manual.  Step 4 is what I believe is making it "fix itself" while you are online.  Servicing communications such is you PC affects the scan time.  Can you post your program?  I'm still leaning towards a data synchronization problem such as the trigger that starts the 526ms timer and the 2 digit divert code coming in at separate times.
  11. 4-20mA applied to 500 ohm resistor.

    Yes, there is nothing that says you have to use the full range of an analog input.  Look at the SCP instruction to scale it into a real world value that you can understand.
  12. RS Logix 500

    Again without seeing you program it is hard to tell, but if there were a timing issue such as a hard wired trigger happening before the 2 digit divert code arriving over the devicenet network or implicit vs explicit messaging, then going online would slow down your scan time slightly which could change the timing of the input vs 2 digit arrival.
  13. 4-20mA applied to 500 ohm resistor.

    You may want to consider using a 250 ohm resistor which would give you 1-5VDC.  Many analog devices have a maximum impedance of 500 ohms so you will be on the edge of what they are capable of driving with a 500 ohm resistor.  See the bottom of this article  in the section titled "Measuring a 4-20ma Input With a Voltage Input Device" for more details
  14. RS Logix 500

    Without seeing your program I can only make wild guesses, but you being online with the controller does affect the controllers scan time.  Are these codes coming over explicit messaging or through mapped I/O points?  If explicit is the a corresponding input that tells you when to read the 2 digit code? What is the scan time when connected?  What type of PLC is it?
  15. RS Logix 500

    What type of instruction are you using to trigger your divert? How long is the input trigger duration?