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Nogmor

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Posts posted by Nogmor

  1. pH Control for Water Tank

    in Vision & Samba PLC + HMI Controllers & VisiLogic Software

    Posted

    Hello Nogmor!

     

    Glad I could have been of assistance!

    I found this rather interesting, and i think it make be of some assistance to you. http://www.omega.co.uk/pptst/CL601_PHCL-602.html

     

    Thanks for the reply,

     

    I am not looking for an actual pH simulator, I figured I could simply program one in the PLC in Ladder, no?

     

    Assining an MI to a virtual pH value, and incrementing/decrementing according to I/O which I activate.

     

    What I'm looking for, is simulating a pH sensor in the PLC itself via ladder-logic, and what I have up to now is not the best of solutions, but it's going O.K.

     

    I just need to make sure it resembels actual pH sensors..

     

    Thanks for your help!

  2. pH Control for Water Tank

    in Vision & Samba PLC + HMI Controllers & VisiLogic Software

    Posted

    Hi Memphis!

     

    I am right now working on such an exact process!

     

    I am in need of a pH Sensor simulator for the PLC which should respond to addition of acid while water is being pumped through a pipe.

     

    I have used a method of simply adding acid when the valve is open (and the pH is virtually lowered) and when it is off, the pH automatically rises (since only water is being pumped).

     

    I would love to see what your final solution is on this issue as it would help me as well.

     

    Thanks!

     

     

    Thank you very much Joe and Simon! Always good to hear that you're going in the right direction.

     

    The pH only needs to be at the set point once everyday, and is then pumped out to another tank. Given that, i decided that over a period of 30/40 minutes prior to pumping, my current program should be able to account for any increases in pH. The acid or base that will be added to the tank can diffuse slowly so i don't want to end up with the program overdosing the acid and then trying to make up for it by adding large amounts of the base.

     

    Due to the fragile nature of pH electrodes, I've decided to place the probe externally to the tank. By pumping water from the tank to an external pipe and back, and then fitting the pH electrode so the part that takes the reading is inside the pipe, i can take more stable readings, as the water inside the 500 gallon tank is being constantly mixed by the pump. Hopefully this will decrease the time required for the mixing stage.

     

    I also hope this will help anyone looking for a basic pH management system, i looked on the forums for a while and couldn't find anything quite like this with attached ladder diagram.

     

    I'll be recieving the pH signal transmitter shortly and will let you know on the success or lack of it!

  8. Slow HMI response time

    in Vision & Samba PLC + HMI Controllers & VisiLogic Software

    Posted

    Hi!

     

    First of all, I would like to say I love your controllers! They are excellent and make work so much more easier and automated.

     

    Second, I seem to have stumbled on a very peculier state in which an HMI screen is simply responding very slow (Slow frame rate?) the scan time is normal: 2 - 4 ms and for some reason only a single HMI screen in the multitude of screens is responding slow.

     

    Controller\PC Setup: V1040 OPLC with V200-18-E3/4XB Snap-In and two expansion units: IO-AO6X and IO-DI16.

    Visilogic 9.4.0 (Having trouble converting to 9.5.0... - for next time) running on Intel Pentium 4, 3.00GHz under Windows 7, 32-bit with 4 GB ram.

     

    The Visilogic itself is a bit slow at times, but I would hardly believe this to have an affect on the PLC itself.

     

    I have about 8 HMI screens on a program, with 8 ladders for each screen. I designed to program to run more than one ladder at the same time, but just to figure this out, I cancled all of them and kept the single problematic HMI screen+ladder running, and still the HMI screen is slow to respond (button pressing, switchs change bitmaps etc).

     

    Even disabling the ladder and simply staying on the HMI is not helpful - even when no ladder logic is being used (accepting voltage) the respons time of the HMI is still slow - and this is just one single screen.

     

    I have found an SI which I believe is the frame rate or a very good identifier of it, since it only changes to a very low number when i am displaying this HMI.

     

    SI 44 - Although it is undocumented anywhere I looked, apparently, changes between 256 and 20 whenever I display the problematic HMI.

     

    Every other HMI screen has SI 44 at 256, but when I display the problematic HMI, SI 44 changes rapidly from 256 to 20-21. Hope it helps you figure it out.

     

    Thanks alot for your help!

     

    Mori

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