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RE: [new_distillers] Re: PID Controller

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  • Gavin Flett
    Now that s what I have been searching for. a lamens description of what a PID and an SSR does. Thanks How do the beer brewers do this then, what kind of W
    Message 1 of 28 , Nov 22, 2012
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      Now that's what I have been searching for. a lamens description of what a PID and an SSR does. Thanks

      How do the beer brewers do this then, what kind of W heating element do they use? Is it multiple low wattage elements?


      To: new_distillers@yahoogroups.com
      From: self.adhesive@...
      Date: Thu, 22 Nov 2012 23:48:08 +0000
      Subject: [new_distillers] Re: PID Controller

       

      > Cool, great info. I am actually using it for a barley mash process. So if I understand correctly, an SSR performs the same functions as a PID, but better?

      No, they're completely different things. The PID is a logic "brain" that attempts according to the parameters you program in to shoot for a particular temperature. It determines how long the element is "on" or "off" and makes adjustments according to results.

      SSR stands for Solid State Relay. It's really just an electronic switch - it has no moving parts. It is the equivalent of the contactor but because the contactor has moving parts it is not capable of switching power off and on to the element frequently without destroying itself.

      Your PID itself is able to switch loads of up to 3 amps, but this is well short of 2000 Watts. Remember that Watts = Voltage x Amps. Re-arrange this formula to get W/V = A, and depending on what your voltage is this will tell you how many Amps capability you need.

      So you employ a contactor, or SSR, to do the heavy-duty switching because these are capable of handling many more amps.

      There is one thing to remember with a SSR, and that is if they fail they switch, as far as I understand, to full on and will not turn off. The SSR has its own connection to voltage mains. So, as with all setups like this, you should always supervise operation.

      Paul


    • Bob Glicksman
      No. You would use an SSR in lieu of a contactor. An SSR can switch the AC power on and off very fast. A zero crossing SSR can cycle AC power every 1/2 cycle
      Message 2 of 28 , Nov 22, 2012
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        No.  You would use an SSR in lieu of a contactor.  An SSR can switch the AC power on and off very fast.  A zero crossing SSR can cycle AC power every 1/2 cycle - every 16.67 ms for 60 Hz power.  So a PID controller can then turn AC on and off to the heater for some number (1 - 120) of half-cycles per second.  A 2 KW heater will not even "see" this fast switching of the AC -- it will just average out the power, giving the PID controller fine grined control over the heat level without any "ripples".
         
        If you use a contactor in lieu of an SSR, the contactor cannot switch very fast.  The minimum time that you can turn the AC power on of off is perhaps 1 second.  So what YOUR PID controller (which is made for use with a contactor) will do is take a 100 second interval and turn the power on to your heater for some integral number of seconds every 100 seconds -- e.g. turn it on for 25 seconds and then off for 75 seconds to give 1/4 power.  Of course, your 2KW heater WILL respond well within a 100 second period and the PID controller will see it heating up (when power is on) and cooling down (when power is off).  However, the heater wil cycle this way only a small part of its heat range.  After all, it takes much longer than 100 seconds to fully heat up and much longer than 100 seconds to fully cool down.  Furthermore, if this controller is doing its job as advertised, it won't turn the heater on for 25 seconds and then off for 25 seconds -- it may turn it on every 4th second for one second only.  This woudl greatly smotth out the heter heat generation profile, but it will cycle the contactor more often and shorten its lifetime.  So your PID controller has some sort of proprietary logic in its programming to provide a best compromise over these actions.
         
        Bottom line:  your PID controller will work with an eletromechanical contactor.  Your model is specifically designed to do this.  It will do a better job of holding the heat constant than a simple thermostatic controller would, but there will be some heat variation owing to the limitations of how fast it can cycle the heater because it is using an electromechanical device (contactor).  Since you have these parts, go ahead and try it.  It will likely work well enough for you purposes.  If it doesn't, please post this result and then I woudl recommend getting a suitable SSR than can handle your 2KW load (at least 10 amps at 220 VAC).  I'll have to look through the data sheet of your controller more carefully to see if the cycling time can be decreased to make best use of an external SSR.  Since it has an internal SSR (not powerful enough to drive your heater directly, though), it may be possible to reconfigure it this way.  If you were to use an external SSR with a PID controller that cycled ona 1 second basis, you woudl be able to hold your temperature extremely steady-- probably more steady than you can reasonably measure.
        -----Original Message-----
        From: Gavin Flett <gavin_flett@...>
        To: new_distillers <new_distillers@yahoogroups.com>
        Sent: Thu, Nov 22, 2012 2:41 pm
        Subject: RE: [new_distillers] PID Controller

         
        Cool, great info. I am actually using it for a barley mash process. So if I understand correctly, an SSR performs the same functions as a PID, but better? If this is the case, can I purchase one that will work with my heating element?


        To: new_distillers@yahoogroups.com
        From: bobg542492@...
        Date: Thu, 22 Nov 2012 14:06:38 -0500
        Subject: Re: [new_distillers] PID Controller

         

        The PID setup is intended to smooth this out somewhat.  The data sheet specifies 1 deg F, but I don't know under what conditions they test this under.  You have to follow the auto-tune procedure in the manual in order for its "fuzzy logic" to learn the time constants of your specific system and figure out when to cycle the heater power on and off so that it doesn't overshoot or undershoot as much as a simple thermostat would.  There is also a thermostat "on/off" mode, but configuring the controller for this mode will probably result in the same amount of overshoot that you experienced previously.  So use the PID mode with auto-tune and let us know who well this controller did for you.
         
        I personally much prefer controllers for SSRs, since SSRs can switch very fast and the PID controller can then use a one second cycle or less vs 100 second cycle for a contactor.  This has a much greater potential to keep a very even flow of heat and thus much tighter temperature control.  This PID controller does have an SSR output, but it is only for 3 amps - too little for your 2KW heater.  It is designed for use with an external contactor and you already have the contactor, so hook it up and see how well it works. 
         
        If you are trying to control heat to control proof in a still, you might be better off to try some sort of automatic reflux control vs trying to keep the heat input controlled very tightly.  The book:  http://www.amphora-society.com/Designing-and-Building-Automatic-Stills-2nd-Edition--by-Riku_p_3.html has a lot of good information about this. 
        -----Original Message-----
        From: Gavin Flett <gavin_flett@...>
        To: new_distillers <new_distillers@yahoogroups.com>
        Sent: Thu, Nov 22, 2012 10:36 am
        Subject: RE: [new_distillers] PID Controller

         
        Ok, so it sounds like a similar method of operation to my Johnston A-419 temperature controller which basically turned it on full blast for a bit, then turned it off. I saw temperature variances of up to 5 degrees. For instance I wanted to achieve a temperature of 64C, and it would end up all the way at 69C. Does the PID setup smooth out the heat fluctuations at all, a little bit or a lot?


        To: new_distillers@yahoogroups.com
        From: bobg542492@...
        Date: Thu, 22 Nov 2012 13:17:21 -0500
        Subject: Re: [new_distillers] PID Controller

         

        Gavin,
         
        I searched out the manual and you should wire it as Jeri suggests.  If you use an external contactor to control power to your heater, the PID controller will cycle it slowly -- turn it on for some number of seconds, then off and repeat every 100 seconds or so.  The heat output from the 2KW heater will vary as this happens, but the PID controller will attempt to hold the temperature as closely as possible.
         
        Bob
        -----Original Message-----
        From: Gavin Flett <gavin_flett@...>
        To: new_distillers <new_distillers@yahoogroups.com>
        Sent: Wed, Nov 21, 2012 11:03 pm
        Subject: RE: [new_distillers] PID Controller

         
        Guys, I don't know the first thing about PID's. The terms used are mostly foreign to me, hence my trouble so far. If this is the wrong setup, then someone please tell me what I need to run a 2000W heating element for a RIMS.


        To: new_distillers@yahoogroups.com
        From: bobg542492@...
        Date: Thu, 22 Nov 2012 00:21:45 -0500
        Subject: Re: [new_distillers] PID Controller

         

        Hi Jeri,
         
        As I said, no I do not have the technical manual.  I was just pointing out that proportional control of the heating element is not possible with an electromechnaical relay.  The heater is either on or off, and the relay cannot be cycled fast enough to make it pseudo-analog.  If a thermostate-like mode is supported by the PID controller, that is fine, as long as this type of operation is acceptable to Gavin.
         
        Bob
        -----Original Message-----
        From: laxt57 <laxt57@...>
        To: new_distillers <new_distillers@yahoogroups.com>
        Sent: Wed, Nov 21, 2012 8:54 pm
        Subject: Re: [new_distillers] PID Controller

         
        Hi Bob
        Did you read the technical publication  for this controller?
        SYL-2372
        I did
        Jeri



        -----Original Message-----
        From: Bob Glicksman <bobg542492@...>
        To: new_distillers <new_distillers@yahoogroups.com>
        Sent: Sun, Nov 18, 2012 9:42 pm
        Subject: Re: [new_distillers] PID Controller

         
        I don't know this particular PID controller, but if it is going to use a PID algorithm (proportional-integral-differential control), then it needs to adjust the heater output, not just turn it on and off.  Some PIDs can rapidly switch an SSR in order to adjust the heat output.  They do this for turning on the relay for some number of AC half-cycles (about 16 ms each half cycle for 60 Hz AC), since the heater's response time is much slower and will average out the electric power being modulated in this way.  But this type of operation requires a fast electric power switching device (an SSR).  A contactor or other electromechanical relay is too slow to do this (and rapidly switching one on and off all of the time will wear it out in notime flat). 

        The only thing that you can realistically do with an electromechanical relay switching power to an electric heater is implement a "deadzone" type of control -- like an ordinary thermostat.  I'm not sure that this PID controller can do this.  Most PID controllers are far more expensive than a simple thermostat and there would be no reason to support this mode of operation.


        -----Original Message-----
        From: laxt57 <laxt57@...>
        To: new_distillers <new_distillers@yahoogroups.com>
        Sent: Sun, Nov 18, 2012 1:03 pm
        Subject: Re: [new_distillers] PID Controller

         
        Hi
        Sure, simple as piece of cake.
        The number 9 and 10 terminals provide power to the PID
        (only for the PID not the heating element)
        The 6 and 7 terminals control a relay for some sort of device
        The 4 and 5 terminals are input from a thermocouple

        So, I assume you are using this to control a heating element?
        To make it work, you will need contactor(relay) big enough to run
        your heating element.
        Also you will need a thermocouple  and a heating element of course
        The thermocouple is polarity sensitive, so you need to connect it
        the right way round, that is if you are asking form hot and you get cold
        swap 4 and 5

        ----------------
        |               |   4---------------- Thermocouple +
        |     PID     |   5---------------  Thermocouple -
        |               |   6---------------  Contactor------------------- coil RELAY--------- heater
        |               |   7---------------- Contactor------------------- coil RELAY--------- heater
        ----------------                                                        AC   AC
          9      10                                                            IN    IN
         AC    AC
          IN    IN

        Hope this helps
        Jeri



        -----Original Message-----
        From: grainbrewer <gavin_flett@...>
        To: new_distillers <new_distillers@yahoogroups.com>
        Sent: Sat, Nov 17, 2012 11:42 am
        Subject: [new_distillers] PID Controller

         
        I recently purchased a PID Controller. Not being at all familiar with electronics, I am having a very difficult time understanding the instructions. Is it possible for someone to read the instructions and translate them into lamens terms for me? Mostly I am unfamiliar with the wiring diagram and symbols.

        The PID is an Auberins SYL-2372 and I have a contacter to go with it model # CN-PBC302-120V.




      • Bob Glicksman
        I m not an expert at beer brewing, but I doubt that the temperature has to be held absolutely steady e.g. to less than +/-0.1 deg C of the desired temperature.
        Message 3 of 28 , Nov 22, 2012
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          I'm not an expert at beer brewing, but I doubt that the temperature has to be held absolutely steady e.g. to less than +/-0.1 deg C of the desired temperature.  I'm somewhat surprised that your previous, simple thermostatic controller wasn't acceptable.  I wouldn't think that the temperature wandering around within a few degrees of the desired temperature would make much of a difference to the biochemcial processes at work here, as long as the desired temperature was optimized for the enzymes, pH , etc.  However, if you want to minimize this "wandering around" and have the temperature come up to some point and stay there rock solid, then you want to use a PID controller, as you are doing.  There is no disputing this!  The only issue here is whether actually having the PID controller use an electromechanical contactor to cycle the AC power to your heater reduces the "wandering" down to an acceptable level.  If not, you need to have the PID controller operate a faster device in order to cycle the AC power faster -- and this device would be an SSR.
          -----Original Message-----
          From: Gavin Flett <gavin_flett@...>
          To: new_distillers <new_distillers@yahoogroups.com>
          Sent: Thu, Nov 22, 2012 4:20 pm
          Subject: RE: [new_distillers] Re: PID Controller

           
          Now that's what I have been searching for. a lamens description of what a PID and an SSR does. Thanks

          How do the beer brewers do this then, what kind of W heating element do they use? Is it multiple low wattage elements?


          To: new_distillers@yahoogroups.com
          From: self.adhesive@...
          Date: Thu, 22 Nov 2012 23:48:08 +0000
          Subject: [new_distillers] Re: PID Controller

           

          > Cool, great info. I am actually using it for a barley mash process. So if I understand correctly, an SSR performs the same functions as a PID, but better?

          No, they're completely different things. The PID is a logic "brain" that attempts according to the parameters you program in to shoot for a particular temperature. It determines how long the element is "on" or "off" and makes adjustments according to results.

          SSR stands for Solid State Relay. It's really just an electronic switch - it has no moving parts. It is the equivalent of the contactor but because the contactor has moving parts it is not capable of switching power off and on to the element frequently without destroying itself.

          Your PID itself is able to switch loads of up to 3 amps, but this is well short of 2000 Watts. Remember that Watts = Voltage x Amps. Re-arrange this formula to get W/V = A, and depending on what your voltage is this will tell you how many Amps capability you need.

          So you employ a contactor, or SSR, to do the heavy-duty switching because these are capable of handling many more amps.

          There is one thing to remember with a SSR, and that is if they fail they switch, as far as I understand, to full on and will not turn off. The SSR has its own connection to voltage mains. So, as with all setups like this, you should always supervise operation.

          Paul


        • Gavin Flett
          Once again,great info, thanks so much for the explanation To: new_distillers@yahoogroups.com From: bobg542492@aol.com Date: Fri, 23 Nov 2012 00:25:52 -0500
          Message 4 of 28 , Nov 23, 2012
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            Once again,great info, thanks so much for the explanation

            To: new_distillers@yahoogroups.com
            From: bobg542492@...
            Date: Fri, 23 Nov 2012 00:25:52 -0500
            Subject: Re: [new_distillers] Re: PID Controller

             

            I'm not an expert at beer brewing, but I doubt that the temperature has to be held absolutely steady e.g. to less than +/-0.1 deg C of the desired temperature.  I'm somewhat surprised that your previous, simple thermostatic controller wasn't acceptable.  I wouldn't think that the temperature wandering around within a few degrees of the desired temperature would make much of a difference to the biochemcial processes at work here, as long as the desired temperature was optimized for the enzymes, pH , etc.  However, if you want to minimize this "wandering around" and have the temperature come up to some point and stay there rock solid, then you want to use a PID controller, as you are doing.  There is no disputing this!  The only issue here is whether actually having the PID controller use an electromechanical contactor to cycle the AC power to your heater reduces the "wandering" down to an acceptable level.  If not, you need to have the PID controller operate a faster device in order to cycle the AC power faster -- and this device would be an SSR.
            -----Original Message-----
            From: Gavin Flett <gavin_flett@...>
            To: new_distillers <new_distillers@yahoogroups.com>
            Sent: Thu, Nov 22, 2012 4:20 pm
            Subject: RE: [new_distillers] Re: PID Controller

             
            Now that's what I have been searching for. a lamens description of what a PID and an SSR does. Thanks

            How do the beer brewers do this then, what kind of W heating element do they use? Is it multiple low wattage elements?


            To: new_distillers@yahoogroups.com
            From: self.adhesive@...
            Date: Thu, 22 Nov 2012 23:48:08 +0000
            Subject: [new_distillers] Re: PID Controller

             

            > Cool, great info. I am actually using it for a barley mash process. So if I understand correctly, an SSR performs the same functions as a PID, but better?

            No, they're completely different things. The PID is a logic "brain" that attempts according to the parameters you program in to shoot for a particular temperature. It determines how long the element is "on" or "off" and makes adjustments according to results.

            SSR stands for Solid State Relay. It's really just an electronic switch - it has no moving parts. It is the equivalent of the contactor but because the contactor has moving parts it is not capable of switching power off and on to the element frequently without destroying itself.

            Your PID itself is able to switch loads of up to 3 amps, but this is well short of 2000 Watts. Remember that Watts = Voltage x Amps. Re-arrange this formula to get W/V = A, and depending on what your voltage is this will tell you how many Amps capability you need.

            So you employ a contactor, or SSR, to do the heavy-duty switching because these are capable of handling many more amps.

            There is one thing to remember with a SSR, and that is if they fail they switch, as far as I understand, to full on and will not turn off. The SSR has its own connection to voltage mains. So, as with all setups like this, you should always supervise operation.

            Paul



          • laxt57@aol.com
            Hi Well, er, ah,mumble*%#** I hate to butt in. But you could use a solid state contactor Switch on and off lots without issue Jeri ... From: Bob Glicksman
            Message 5 of 28 , Nov 25, 2012
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              Hi
              Well, er, ah,mumble*%#** I hate to butt in.
              But you could use a solid state contactor
              Switch on and off lots without issue
              Jeri







              -----Original Message-----
              From: Bob Glicksman <bobg542492@...>
              To: new_distillers <new_distillers@yahoogroups.com>
              Sent: Thu, Nov 22, 2012 11:17 pm
              Subject: Re: [new_distillers] PID Controller






              No. You would use an SSR in lieu of a contactor.
            • Fredrick Lee
              Gavin, I own a 12HL (a little less than 300 gallons) brewery and we use a 6000W RIMS tube for our mash tun temp changes. Two things we have solved that have
              Message 6 of 28 , Nov 26, 2012
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                Gavin,
                   I own a 12HL (a little less than 300 gallons) brewery and we use a 6000W RIMS tube for our mash tun temp changes. Two things we have solved that have made this possible. 

                1.) We realized not only did we need to know the temp of the grain bed (mash temp), we also needed to know the temp of our RIMS tube output (rims temp).  We were recirculating our wort out of the RIMS back into the mash tun near the top (I think some breweries call this the "vorlauf"). This freshly heated wort would remain at the top of the mash, and only slowly work it's way down until it was replaced by enough hot wort to reach the thermometer. Often overshooting your the mash temp and denaturing the enzymes that were responsible for starch conversion; depending when this occurs, we could end up with significantly less sugar to ferment.  We solved this problem by averaging the mash temp and the rims temp. Most PIDs cannot do this, so for a while we used pencil and paper with a manual thermometer on the mash tun and PID (with SSR) on the RIMS tube. After a bit of mucking around we discovered this problem on our 100liter (about 20 gals) system too. 

                2) we feel like everyone should take good care to have a gentle vorlauf, it will rebuild the grain bed to act as a filter for the husks and whatnot. Clear flowing wort ferments better and leaves less residue in your kettles and fermenters. Low splashing and avoiding wort from channeling through the grain bed will make things much better for in the boil and subsequently whirlpooling, chilling and fermenting. 


                On Nov 22, 2012, at 7:20 PM, Gavin Flett <gavin_flett@...> wrote:

                 

                Now that's what I have been searching for. a lamens description of what a PID and an SSR does. Thanks

                How do the beer brewers do this then, what kind of W heating element do they use? Is it multiple low wattage elements?


                To: new_distillers@yahoogroups.com
                From: self.adhesive@...
                Date: Thu, 22 Nov 2012 23:48:08 +0000
                Subject: [new_distillers] Re: PID Controller

                 

                > Cool, great info. I am actually using it for a barley mash process. So if I understand correctly, an SSR performs the same functions as a PID, but better?

                No, they're completely different things. The PID is a logic "brain" that attempts according to the parameters you program in to shoot for a particular temperature. It determines how long the element is "on" or "off" and makes adjustments according to results.

                SSR stands for Solid State Relay. It's really just an electronic switch - it has no moving parts. It is the equivalent of the contactor but because the contactor has moving parts it is not capable of switching power off and on to the element frequently without destroying itself.

                Your PID itself is able to switch loads of up to 3 amps, but this is well short of 2000 Watts. Remember that Watts = Voltage x Amps. Re-arrange this formula to get W/V = A, and depending on what your voltage is this will tell you how many Amps capability you need.

                So you employ a contactor, or SSR, to do the heavy-duty switching because these are capable of handling many more amps.

                There is one thing to remember with a SSR, and that is if they fail they switch, as far as I understand, to full on and will not turn off. The SSR has its own connection to voltage mains. So, as with all setups like this, you should always supervise operation.

                Paul


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