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    Another water pump automation project (suggestions ?)

    Good day folks. Some of you may recall that a while ago I was struggling to put together what I considered to be a very basic automation for a water supply system. It didn't work out the way I intended and I learned my lesson to do it properly from the start, rather than try to reinvent the wheel and patch something together myself from scratch, so I'll stick to commercial alternatives for future projects and such a project just came in today !

    This one is easier simply because this time the pump and level sensors are in the same place, so they don't require a remote connection. The client DOES require remote control and monitoring though. I'll let the doodle speak for itself, instead of trying to describe it too much: two separate tanks, one pump for both, 2 valves, 2 float switches - make sense ?

    Not wanting to DIY it and fail again, I began searching for OTS solutions, which brings me to the actual topic: I'd appreciate suggestions from people who happen to work in the field and/or have more experience with industrial automation than I do

    Several things I thought of:

    - some sort of PLC (Siemens, Schneider). The most professional approach, but also the most pricey and requires the most work, because I'd need to come up with some sort of web server, which is the the hardest bit. I HAVE played with PLCs before at a very basic level, but never with more advanced features like control over ethernet.

    -a GPRS/4G solution like a gate opener: easiest to implement out of the box, plus it only requires a SIM card to get it online. Not the most visually appealing to use - no GUI: the most it can do is return SMS messages when the status of the floats flips and the pump turns on/off. Many of these don't have more than 2-3 outputs, which is a bit close for comfort and leaves no room for further expansion. They may also not support any IF-THEN functions, so I may not be able to map input 1 to outputs 1 AND 2 simultaneously...

    -Shelly Pro 4PM: this one almost won, but not quite. Cheap, app is ready to go out of the box, has 4 inputs and 4 outputs, has ethernet, is DIN-rail compatible. What killed it is that, according to the manual, there's no isolation. The inputs are referenced to the "hot" wire - no low voltage control - so I'd have to pass 230v through the float sensors underwater and in humid environment ??? Yikes ! I WAS thinking of taking it apart and getting it down to the bare-minimum, which I'm sure is like a transistor/optocoupler+resistor divider jobbie, dropping the 230v to pull the respective pins of the microcontroller low/high, but that's not 100% guaranteed....

    Any more ideas ? Thanks.
    Wattevah...

    #2
    Re: Another water pump automation project (suggestions ?)

    My suggestion would be to show a pictorial of what you have and where you want to go. Leave spaces in the diagram to fill in what you may not know at a later time. Put things in block diagram. With such a picture one can then work on each part of the diagram. Then people on the site who may be better at certain parts of the block diagram can help you with each part of their expertise. That would be my suggestion to You.

    Comment


      #3
      Re: Another water pump automation project (suggestions ?)

      the large nucleo boards can run a web server - there is even example code for it online to communicate with a phone browser
      but why??
      and whats to control??
      the pump fills the tanks till the floats stop the pump - job done.
      no need for a fucking computer - it's not made by mercedes

      Comment


        #4
        Re: Another water pump automation project (suggestions ?)

        Yeah, my bad: I promised a diagram and forgot to add it Here it is....in all its MS Paint glory

        The principle of operation: when either float switch drops down (so that tank is low on water), it activates the pump AND the respective solenoid valve to fill that particular tank, independent of the other. Obviously, we don't want to run the pump with both valves closed. Sounds simple and I would've done it without any micro at all, using just relays, but I got hung up on the client's requirement to be able to inquire the status of either tank and switch on the pump on demand (along with the respective valve of course).

        Now when I say "status", in this implementation, it can only know whether the float is up (one contact closed) down (other contact closed) or in-between (neither contact closed) - it won't have any way of knowing the actual level, so it's just a dumb DPST switch there and there's no need to obsess over that too much. It's the user interface I'm most interested in, plus it's an opportunity to learn how to expand such a system in the future, for a remote pump, like I tried to do last time.
        Attached Files
        Wattevah...

        Comment


          #5
          Re: Another water pump automation project (suggestions ?)

          are both tanks side by side?

          Comment


            #6
            Re: Another water pump automation project (suggestions ?)

            For these projects, you start with a list of the I/O required, and the voltages/currents for the I/O. This is the "point list" or "tag list" as it can be called, put into an Excel spreadsheet.
            This is to know what size controller is required. Small ones have say 8 DI's, 8DO's but are typically 24VDC I/O which can cause a hassle if you need to switch 240VAC contactors. Also the existing manual panel pushbuttons etc. likely need to be reused.

            Comment


              #7
              Re: Another water pump automation project (suggestions ?)

              So, I was thinking a little more like this. Then take each block and break it down into components and software. The pressure cut-off switch should be on the input of the pump. One can restrict the output of the pump some but, the input has to run without restriction otherwise the pump will overheat and burn out.
              Attached Files
              Last edited by keeney123; 07-26-2022, 09:04 PM.

              Comment


                #8
                Re: Another water pump automation project (suggestions ?)

                Let's review then:
                Originally posted by redwire View Post
                For these projects, you start with a list of the I/O required, and the voltages/currents for the I/O. This is the "point list" or "tag list" as it can be called, put into an Excel spreadsheet.
                This is to know what size controller is required. Small ones have say 8 DI's, 8DO's but are typically 24VDC I/O which can cause a hassle if you need to switch 240VAC contactors. Also the existing manual panel pushbuttons etc. likely need to be reused.
                At the moment there's nothing there: it's all done manually, though you're right: some sort of local control panel will need to be implemented using a couple of buttons and a few indicator lights.

                There should be no problem driving a 230V/400V contactor via a 24v relay, right ? (aside from maybe the EMI it produces when it cuts out).

                At its bare minimum, I'd need 3 outputs (1 pump, 2 valves) and 2 inputs (two float switches). This is not only hard to find, but also counter-productive because it leaves no room for expansion later on. I'd go with a 4 or 8 I/O controller - say they add another tank and I need another float. Most controllers I found, like I said, either do too much or too little.....or they look rather generic, homebrew even, and don't inspire much confidence when it comes to quality and resilience over time the way a proper brand does. PLCs are expensive and require a lot of work to get going, especially since I haven't worked with them too much, much less so when it comes to programming some sort of web server that ACTUALLY interfaces with the I/O. If it weren't for the remote management aspect, I would've gone with a PLC I have lying around, that my company's willing to sell anyway - this one.

                The project's not too big of a deal, so I shouldn't go too overboard in complexity and cost....the way I usually do

                Originally posted by stj View Post
                are both tanks side by side?
                Yes, they are.
                Wattevah...

                Comment


                  #9
                  Re: Another water pump automation project (suggestions ?)

                  if the tanks are side-by-side then you dont need valves.
                  you couple the tanks with a pipe at the high-water line and when one is full it will transfer incoming water to the other tank until both are equal.
                  this is how the wing fuel tanks in some cars operate.
                  wire the level sensors in series to the pump so both tanks full = pump off.

                  Comment


                    #10
                    Re: Another water pump automation project (suggestions ?)

                    From what I understand, the setup is already in use, just not automated, so we're in charge of doing only that. I won't be altering any of the existing pipework. I have not seen it personally - my sole concern is the "brains" of this system
                    Wattevah...

                    Comment


                      #11
                      Re: Another water pump automation project (suggestions ?)

                      If this thing was running manually before, why the change to web control? A raspberry pi has 26 GPIO pins that are programmable. Also you can cluster them.

                      Comment


                        #12
                        Re: Another water pump automation project (suggestions ?)

                        Originally posted by CapLeaker View Post
                        If this thing was running manually before, why the change to web control? A raspberry pi has 26 GPIO pins that are programmable. Also you can cluster them.
                        Because people want to upgrade and automate the process

                        I'm afraid a Raspberry Pi would be too much work and too fragile of a product.
                        Wattevah...

                        Comment


                          #13
                          Re: Another water pump automation project (suggestions ?)

                          Originally posted by Dannyx View Post
                          From what I understand, the setup is already in use, just not automated, so we're in charge of doing only that. I won't be altering any of the existing pipework. I have not seen it personally - my sole concern is the "brains" of this system
                          So, what you need to do is to go see the system. Take Clear photos of the present system and post them. Make drawings of what the photos do not show and post them. Then everyone will know what you are working with, and you will get more definitive replies to help you.

                          The drawings can be pencil and paper and does not need to be on paint program. After you make the pencil drawing at the site then bring in back to your home and make and black ink drawing. Then post the black ink drawing.

                          Also, know that when you design a system you will need to think of every perceivable way the system can fail and then prevent any damage when it fails.
                          Last edited by keeney123; 07-27-2022, 12:42 PM.

                          Comment


                            #14
                            Re: Another water pump automation project (suggestions ?)

                            Originally posted by keeney123 View Post
                            So, what you need to do is to go see the system. Take Clear photos of the present system and post them. Make drawings of what the photos do not show and post them. Then everyone will know what you are working with, and you will get more definitive replies to help you.

                            The drawings can be pencil and paper and does not need to be on paint program. After you make the pencil drawing at the site then bring in back to your home and make and black ink drawing. Then post the black ink drawing.

                            Also, know that when you design a system you will need to think of every perceivable way the system can fail and then prevent any damage when it fails.
                            Yes, it was mostly speculative. I was curious to hear how others would tackle such a job.
                            Wattevah...

                            Comment


                              #15
                              Re: Another water pump automation project (suggestions ?)

                              Originally posted by Dannyx View Post
                              Because people want to upgrade and automate the process

                              I'm afraid a Raspberry Pi would be too much work and too fragile of a product.
                              Usually in a system that links integrated circuits with power circuits either a opto isolator is used or control relays are use. This is done to prevent damage to fragile low voltage IC circuits.

                              Comment


                                #16
                                Re: Another water pump automation project (suggestions ?)

                                Originally posted by keeney123 View Post
                                Usually in a system that links integrated circuits with power circuits either a opto isolator is used or control relays are use. This is done to prevent damage to fragile low voltage IC circuits.
                                Correct, which is why I cannot be bothered to cobble up something from scratch again. We're going OTS this time.
                                Last edited by Dannyx; 07-27-2022, 01:51 PM.
                                Wattevah...

                                Comment


                                  #17
                                  Re: Another water pump automation project (suggestions ?)

                                  We would start with a site visit- collect drawings, wiring diagrams etc all existing documentation for the site. Take a lot of pictures, to get wiring, part numbers etc of the existing equipment.

                                  You can't use a cheap chinese PLC because their software is decades behind and who wants CapXon reliability? What keeps killing you is the cheap low budget you have.
                                  A custom solution using Arduino/RPi etc is a "one of" - nobody but you know how it works. Yes it was cheap (hardware) but still alot of work to build (hours programming).

                                  I was thinking you could break it down from the other direction - the web server, WiFi etc HMI and see what controllers can do that, first.
                                  Either that or split it up, a vanilla PLC with MODBUS over to a webserver. But it's more complicated to program two systems instead of one.

                                  Comment


                                    #18
                                    Re: Another water pump automation project (suggestions ?)

                                    Originally posted by Dannyx View Post
                                    Correct, which is why I cannot be bothered to cobble up something from scratch again. We're going OTS this time.
                                    The critical part for you is going to be the matting of systems. You are going to need to know the full operation on the end of one system and the beginning operation of the other system. The sequential function of the systems must be fully understood, and the voltage and current requirements of the mated systems will have to match up. This will require figuring out these requirements.

                                    Comment


                                      #19
                                      Re: Another water pump automation project (suggestions ?)

                                      Originally posted by redwire View Post
                                      I was thinking you could break it down from the other direction - the web server, WiFi etc HMI and see what controllers can do that, first.
                                      This is precisely why I launched this thread - to hear what others have used and what they may suggest hardware-wise for a small project like this. It's not a powerhouse at the end of the day.

                                      I started looking for something that meets as many of my requirements as possible, that's both decent quality and relatively affordable. The first thing I decided to leave out in order to get more results is the GSM/4G feature. I was planning to have this thing operate via a SIM card for me and the client's convenience, but there don't seem to be that many options that do this out of the box - they're either "primitive" gate opener kind-of devices, or they're proper PLCs but require an add-on module to implement GSM, which is not only costly but probably hard to get going for a novice. The few PLCs that seem to do GSM out of the box are way overkill - too many I/Os and too expensive, wired Ethernet it acceptable at this point. I can always run that through a 4G modem to get it on the air.
                                      Wattevah...

                                      Comment


                                        #20
                                        Re: Another water pump automation project (suggestions ?)

                                        I found something that looks promising here. I haven't looked too deep into it and the only way to learn something is to actually do it I might ask the guys in supply to get one of these to try out for R&D purposes...
                                        Wattevah...

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