Wild Bill

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  1. PID and my dumb boss

    I'll try the HSC module and go from there. Should work just fine, but then again, it's a SLC 5/02, but should work. Thanks for the help folks.
  2. PID and my dumb boss

    Needless to say, I am not happy with the boss right now. Here is the problem. We have a small motor, DC, 0 to 10 volts that has its speed controlled by a old electronic (Home made) PID controller. Speed is 0 to 1950 rpm and it uses a small encoder as the feed back to the controller. The system works very well, but, if it works, this is not good enough for the powers that be. Ron gave me some real good help with PID in the past, but now I have this question. How do I incorporate the feedback loop from the encoder. We currently use a PC with a D/A converter connected to the motor and another A/D converter connected to the PC for the feedback. Please don't ask me about the program used by the PC. Thats top secret!!! The PLC is a SLC 5/02 using a 1746-NIO4V analog input/output card residing in slot 5. I put it there. The PLC is configured correctly and I have connected another motor to the output for the time being so I can play some. But how do I wire the encoder feedback and use it in the PID control?
  3. Latching Inputs?

    Thanks folks for the help. I did take a look at the thread and saw some interesting ideas. It just didn't make sense to me to latch an input with the exception as Ron had said, in troubleshooting. However, I am a firm believer that OTL is not to user friendly unless you really know what you are doing, and I dont!!! Thanks again. Wild Bill
  4. Latching Inputs?

    I ran across a program that was sent to me by someone that was using an input to latch an input. -------[ ]------------[ L ]-------- I:1/0 I:1/1 Why and what would the rationale be behind this????? Has anyone ever seen this being used???
  5. PID setup

    Ron, Just a note to let you know that your input was of real great value. We are now running on a test basis and seems to be working pretty well. Need some minor adjustments but looks good so far. thanks for all your help. It's greatly appreciated. Bill
  6. PID setup

    Ron, Thanks for all the information. I was able to get the thing to work but see where you are comming from on the thermocouple transmitter voltage. No its not 0 volts at 260 degrees Its like around 2.3 volts. So I have some work to do yet but I think I have a handle on it now. I'm sorry about the SIM program. Wasn't aware that AB would have a simulator that only works on part of the functions. After you mentioned that, I researched the SIM 500 program and saw that there is a lot of stuff it does not support. Thats kind of odd for a simulator to only work on half the functions. But the good news is that I have some sembalance of a program working now and I see that you cant use a SCP function for the input to the PID. It dont like that too much. Faulted every time. I used your snap shot and finally got an output and now will work on the fine tuning of it. God, I did a lot of reading over the weekend on this but it is paying off. Again thanks for all the input. BobLfoot, Bob O, Ken and Peter were a big help also so I need to let the all know. Now, off to see if I can maintain an over temperature. After seeing all the bad about thermocouples, I will most likely suggest going to a RTD for better stability and accuracy. Thanks Bob. Your great!!!
  7. PID setup

    Ron, I tried your settings but was not aware that SIM didnt work with a PID. I played with the numbers trying to get something to change and after I read this post I felt like an idiot. Will give your example a try in the morning. I'm sure your information will work. Question though, why did you circle the SCP function? Am I doing this wrong or is it not needed? Something tells me that the PID needs the real analog card inputs to work and not a scaled input. ?????????? I will work with it in the AM and will let you know of mu success. Bill
  8. PID setup

    Ron, Yes I am rumming SIM to test the program here at home. didnt know that SIM dont do PID. when I load the program into an actual PLC it dont work. The valve does go closed at the temp decreases. Do have a thermocouple transmitter that puts out voltage. Actually the program goes nuts. I'm going to incorporate your ideas tomorrow in the shop at work and see what happens.
  9. PID setup

    Ron, I know the valve works with a SCP function for the output O:1/0 as I wrote a 2 rung program to scale the input and the output. By changing the input I can see the output change accordingly, so the SCP on the input works fine, I think. The RSS file I attached is a starting point and I'm using it on a test SLC 5/03 prior to going on line. With what I have I'd have a lot of fire riddled chocolate chips in the oven.
  10. PID setup

    Like I said, I'm new to PID. so here is the information: SLC 5/03 with a 1746NI04V 2 in/out 0 to 10 volt card. Using a Thermocouple as the input and the SCP instruction to scale for 260 to 300 degrees. My output for the SCP is N10:28. (Using the AB reference manual here). The PID control block is N10:0 Process variable is N10:28 Control variable is N10:29 And the block length is 23 My output to the oven is an analog device controlling a valve modulating from closed to full open. If i knew how to attach the RSS file, I would, but cant find any place to do an attachment on this board. If I;\'d learn to read some I'd see it below!!!!!!!! So, I have attached what I have started. I know the output must be scaled to the valve which is also 0 to 10 DC an I plan on using the SCP function here also. But, where is the output of the PID?????? Am I stupid or what or just dont see whats happening in the PID.PID_TEST.RSS
  11. PID setup

    Bob, Thanks for getting back. My input is going to a SCP instruction which is simple enough. Setting up the PID seems simple enough. My big problem is with the set up screen for the PID. I'm kind of lost there.
  12. PID setup

    I need help with setting up a PID control and have never done this. Using a SLC 5/04 with a 2 input/2 output 0 to 10 volt DC analog card in slot 1. I need to control temperature in an oven from 260 to 300 degrees with a setpoint of 280 degrees. Yes I make cookies and we are now installing AB SLC's to do the controls and I have very little training and AB's site is not too user friendly. I need information on just how to program this into the PLC. Any help would be really appreciated and I'll even include a box of cookies. WildBill