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  • Wireless PID controller?

    10 years ago I converted my heat treat oven to a PID control. I had intended at the time to eventually add a time delay relay,so one of the alarm outputs would start the timer counting down the soak time and then automatically turn the oven off when timed out. I never got that far, so the otherday when pack hardening a mild steel part, the soak time went from 3 hours to 16 hours

    So I was going to embark on my original plan,but then thought why not Wifi or Bluetooth to my phone? Looking online I found just one wireless PID control from a company in Italy, but it looks like it is intended for homebrewing and costs 170 Euros, so not exactly cheap. Anybody got some ideas for a work around? If nothing else if I could just have an alarm on my phone when the furnace reaches set temp that would be a big help.
    I just need one more tool,just one!

  • #2
    There are quite a few commercial PID controllers with serial built in. Tie that in with a serial to wifi adapter and you can control it remotely. You'll have to write the interface though. If it was on a PC I'd say labview because its free for home use. Another option is to use a rs232 to uart chip and something like an esp8266 with a built in web server and you could write a little interface on there and send commands to the PID controller.

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    • #3
      What exactly do you need to do? Would a PID ramp Soak control do it for you? Red Lion makes one as do many others, many cheaper than RL. Reading your post again it sounds like your original plan is the easiest and with new time relays you can easily get relays that can time from seconds to many hours with a few switch settings. These relays are also fairly inexpensive....
      Robin

      Happily working on my second million Gave up on the first

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      • #4
        imo opinion, if you are a mean, nasty, sadistic type, there may be a future for you in PID design and instruction manual writing. Just awful that in this era you're expected key in so many different fields and info from a few stupid little buttons while trying follow those miserable instructions that are near impossible to understand for a beginner.

        I put one in that has a USB connection and use software to program the PID. Its about the shlttiest bit of software ever written (really really bad) but entry via laptop is a quantum leap forward from the PID user interface. It lets you type out in a table form the different segments of a cycle as well as query and display whats in the PID. Big improvement, but it does stupid stuff. Like you set R1 to 60 minutes, write it to the pid, then query the pid and it shows 6 min. In the query screen, you change it to 60, but its really now 600. Stupid crap like that that makes consider the program a real POS.

        A well done phone application, showing the ramps on chart that you could click on and change is how it could and should be, but the above on the laptop is a step in the right direction. You've got a serial connection on the PID and blue tooth modules are available for Arduino....but what do you to for the program on the phone? That's I think where the heavy lifting is .
        Last edited by Mcgyver; 01-11-2022, 06:49 AM.
        in Toronto Ontario - where are you?

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        • #5
          Originally posted by Mcgyver View Post
          imo opinion, if you are a mean, nasty, sadistic type, there may be a future for you in PID design and instruction manual writing. Just awful that in this era you're expected key in so many different fields and info from a few stupid little buttons while trying follow those miserable instructions that are near impossible to understand for a beginner.

          I put one in that has a USB connection and use software to program the PID. Its about the shlttiest bit of software ever written (really really bad) but entry via laptop is a quantum leap forward from the PID user interface. It lets you type out in a table form the different segments of a cycle as well as query and display whats in the PID. Big improvement, but it does stupid stuff. Like you set R1 to 60 minutes, write it to the pid, then query the pid and it shows 6 min. In the query screen, you change it to 60, but its really now 600. Stupid crap like that that makes consider the program a real POS.

          A well done phone application, showing the ramps on chart that you could click on and change is how it could and should be, but the above on the laptop is a step in the right direction. You've got a serial connection on the PID and blue tooth modules are available for Arduino....but what do you to for the program on the phone? That's I think where the heavy lifting is .
          Amen, I don't think there is a more universally hated interface than whats on the garden variety PID.
          I just need one more tool,just one!

          Comment


          • #6
            Originally posted by macona View Post
            There are quite a few commercial PID controllers with serial built in. Tie that in with a serial to wifi adapter and you can control it remotely. You'll have to write the interface though. If it was on a PC I'd say labview because its free for home use. Another option is to use a rs232 to uart chip and something like an esp8266 with a built in web server and you could write a little interface on there and send commands to the PID controller.
            Wireless control from a phone has gotten simple. I used one of these to setup the door and hoist controls on a buddy's boathouse. https://www.tinyosshop.com/8-channel...te-control-kit
            It literally took longer to set it up in an enclosure and wire the power supply than it did to setup and use. It's looking like getting status information from the PID to the phone is where the heavy lifting would be. It might be best to set up a wireless webcam and just look at the PID every so often
            I just need one more tool,just one!

            Comment


            • #7
              Originally posted by rdfeil View Post
              What exactly do you need to do? Would a PID ramp Soak control do it for you? Red Lion makes one as do many others, many cheaper than RL. Reading your post again it sounds like your original plan is the easiest and with new time relays you can easily get relays that can time from seconds to many hours with a few switch settings. These relays are also fairly inexpensive....
              I already have a PID that's controlling the furnance. What I would like is for the PID control to let me know when it reaches set temp, at which point I could just set my phone's alarm to count down the desired soak time.
              I just need one more tool,just one!

              Comment


              • #8
                A 45 dollar raspberry pi and some quick fiddling with Node Red would be what I would use.
                You can even eliminate your existing PID with this https://flows.nodered.org/node/node-red-contrib-pid or if your existing PID has an input you could use the Pi GPIO to trigger it.
                I used this arrangement to automate my greenhouse and to monitor my second property from my phone or PC, it is slicker then a hens tit...
                Cheers,
                Jon

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                • #9
                  ah, so your PID is not programmable? This is what I have https://www.thermomart.com/PID-Tempe...mp-Soak-USB-PC. i've used mine for annealing and lost wax casting, both of which require ramps/programming. imo its a necessary feature on an oven. For $100, and in the spirit of just getting on with it (i'm now in the mindset of eliminate additional time sucking projects that won't change my life), grab one of the above and program it from a lap top. As crappy as the software is its way ahead of PID interface entry and programmable is way ahead of not programmable.....and it'll be 100x faster than rolling your own (and the part won't know the difference )
                  in Toronto Ontario - where are you?

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                  • #10
                    I retired ten years ago so the tech has changed since then. The equipment I worked on was in an industrial area where there was lots of electronic noise. Because of the noise they would not use blue tooth for pid or any control function. Comm wiring was separated from 120 v control wiring. Comm wire shield was grounded on one end, and panel doors were kept closed.

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                    • #11
                      Oh, come on now. None of you have a "PID". You have ovens or furnaces with PID control algorithms, running in a continuous loop, in the temperature controller's firmware. Do any of you call the oven in your home a PID? It has a PID control algorithm as well as all the other features of your shop oven. "Honey, I just put a cake in the PID. I'm going next door for a while, please take it out when it's done. Oh, and don't forget to turn off the PID."

                      The PID loop, once the correct setup parameters are entered, ensures that the set point (SP) temperature isn't exceeded, that you ramp up or down to the SP temperature in optimal time, that there are no spikes in temperature, and that you don't over or under-shoot the SP temperature. In other words, the temperature profile that you get is the same as the one you've programmed.

                      Many variables have to be accounted for when setting up a temperature control PID loop, including the heating capacity of the oven, the thermal mass, size, and shape of the oven, and the size and mass of the object being heated. If you're heating the same part over and over, and only that part, the PID parameters can be setup once and forgotten. If you're heating a different part each time you use the oven, you'll either need to retune the loop each time (enter new parameters) or accept the fact that the loop may not be optimized. To minimize that, most modern controllers, including the one Mcgyver pointed out, have a PID auto-tuning feature, eliminating the need to manually enter new tuning parameters each time the part is changed. Make sure whatever controller you end up with has auto-tuning.

                      Programming the controller requires the operator to enter the temperature profile for the particular item being treated. That includes entering the temperature SPs, dwell/soak times, and possibly other events like turning on a relay or sounding an alarm. The ramp times (time to change from one temp SP to the next) are determined mostly by the PID loop.

                      The controller at Magyver's link can be programmed for up to 30 temperature SP and 30 soak periods. In the OP's example he needs to get to a set temperature, soak at that temperature for a period of time, cool down, and turn off the oven once the item has cooled. These few steps are easily entered from the controller's front panel. That's what I do with my ancient controllers, but a computer interface, as crappy and frustrating as it might be, allows the user to store profiles by name and reload them on command. That's pretty sweet, especially if the profiles are complex or if you've generated a lot of them over time for the various parts you make. The downside is that you always need a computer nearby. I don't know if that controller saves the PID parameters each time it saves a programmed heating profile. That would be nice but it's not a necessity with auto-tune.
                      Last edited by genea; 01-11-2022, 05:12 PM.

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                      • #12
                        Originally posted by Mcgyver View Post
                        ah, so your PID is not programmable? This is what I have https://www.thermomart.com/PID-Tempe...mp-Soak-USB-PC. i've used mine for annealing and lost wax casting, both of which require ramps/programming. imo its a necessary feature on an oven. For $100, and in the spirit of just getting on with it (i'm now in the mindset of eliminate additional time sucking projects that won't change my life), grab one of the above and program it from a lap top. As crappy as the software is its way ahead of PID interface entry and programmable is way ahead of not programmable.....and it'll be 100x faster than rolling your own (and the part won't know the difference )
                        Yes,it is,but I don't want to use programming for the soak time. I used the auto tune feature when I installed it, I even mapped the current draw so I have the most efficent ramp to set point profile.I even added a separate thermocouple and analog pyrometer to use as a tell tale. So far it works perfectly and always arrives at SP on time. That much I am happy with all I really need is to know when SP is reached.After that it's all on me anyway.
                        I just need one more tool,just one!

                        Comment


                        • #13
                          Originally posted by genea View Post
                          The controller at Magyver's link can be programmed for up to 30 temperature SP and 30 soak periods. In the OP's example he needs to get to a set temperature, soak at that temperature for a period of time, cool down, and turn off the oven once the item has cooled. These few steps are easily entered from the controller's front panel. That's what I do with my ancient controllers, but a computer interface, as crappy and frustrating as it might be, allows the user to store profiles by name and reload them on command. That's pretty sweet, especially if the profiles are complex or if you've generated a lot of them over time for the various parts you make. The downside is that you always need a computer nearby. I don't know if that controller saves the PID parameters each time it saves a programmed heating profile. That would be nice but it's not a necessity with auto-tune.
                          I'm dealing with two different types of "soak", neither requires a ramp down. I used the auto tune feature to establish the ramp to SP, it works perfectly and is saved as the default. All I really would like is to know when the SP temp is reached. It's all manual after that anyway.
                          I just need one more tool,just one!

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                          • #14
                            Look up kiln ramp controller.

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                            • #15
                              Omron E5CC-QX2ASM-802 from AliExpress?

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