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    PT100 and PT1000 Breakout Board with MAX31865

    Scheduled Pinned Locked Moved MAX31865 PT100 and PT1000
    pt100max31865arduinopt1000rtd
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    • CharlesC Offline
      Charles
      last edited by

      Oh sorry I wasn't aware that Adafruit Feather could be other than ESP8266 😉
      you're using a one with atmel32u4 ?

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      • G Offline
        gruenst
        last edited by

        No, M0 Adalogger, so it's the atsamd21, should run on 48MHz.
        0_1463608398862_adalogger.jpg
        But even with a clock divider of 16 it wouldn't work.
        I think there must be a hardware issue somewhere in the sketch.

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        • CharlesC Offline
          Charles
          last edited by

          @gruenst
          Well I've not tried the sketch on another target than ATMega 328, what would be best to test your hardware interface, would be to test with a cheap 3V3 nano/arduino to connect your hardware with and launch example sketch. This will for sure indicate if your hardware is working well.

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          • G Offline
            gruenst
            last edited by

            Alright, I ordered one of your boards. That way it's easier to see if it's a problem of the "simpler" arduino boards, or an assembly problem / change of sketch.
            Did you check if VDD/DVDD shows 2.8V or 3.3V when connected with a "proper" Arduino?

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            • B Offline
              BlackBrix
              last edited by

              Hi,
              I just found this project on tindie and I think I should order some ...
              from the arduino library I can see that it is maybe only supporting temperatures grater than 0°C (?) in an exact way ?
              (cause the RTD_C constant is not used ?)
              It would be great to fix this (or maybe I can extend the library myself) for temperatures below 0°C
              The formulas are quite simple, I found them here --> https://24max.de/elektronik/Pt100-Formulas.pdf

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              • CharlesC Offline
                Charles
                last edited by

                @BlackBrix
                What to you mean by greater from 0°C, it works fine on my tests

                But may be you meant lower than 0°C ? To be honest I didn't tested that one, I need to check, but I think it should works

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                • G Offline
                  gruenst
                  last edited by

                  Hi Charles,
                  I tried your breakout board with the same setup I used for mine, and it works. So it's not the software, and not the Arduino Feather board. Must be the difference in setup of the breakout board.

                  I solved an issue with the ground pin, so DVDD and VDD now both show 3.3V.
                  Further, I connected Force2 with Force+ instead of Ground (different to the diagram above), to adapt it to yours. Which doesn't change anything. It shouldn't be the difference in packaging, as SSOP takes less power than your TQFN. So the only difference I see are the two ferrite beads, which I don't use.
                  Which ones do you use? Or would you see a mistake I made with the assembly shown above?

                  Thanks!
                  Stefan

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                  • CharlesC Offline
                    Charles
                    last edited by

                    @gruenst
                    the ferrite board (470 Ohm) are used to do

                    • FB1 Filtering AVDD
                    • FB2 Filtering AGND

                    But you can bypass them, ie put a wire instead, should also work

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                    • F Offline
                      Fernando Vinícius G. Magro
                      last edited by

                      Hi CHARLES,
                      Can you give me information (specs) about the SMD FB1 and FB2 ?
                      There is a Mouser or Digikey part number for this item?
                      Thanks

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                      • CharlesC Offline
                        Charles
                        last edited by

                        @Fernando-Vinícius-G-Magro
                        the Mouser link was in my previous response but it's a 470 Ohm classic Ferrite Board
                        http://eu.mouser.com/Search/ProductDetail.aspx?R=BLM18PG471SN1Dvirtualkey64800000virtualkey81-BLM18PG471SN1D

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                        • E Offline
                          Erik van Os @Charles
                          last edited by

                          @Charles
                          Hi charles,
                          have a question about your nice project, can I use it also for a Raspberry PI 3B?
                          thanks Erik van Os

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                          • CharlesC Offline
                            Charles
                            last edited by

                            @Erik-van-Os
                            thanks, yes for sure you can use it with RPI3 but you'll need to adapt the code, may be using WiringPi library.

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                            • R Offline
                              Roelof Loots
                              last edited by

                              Hi Charles, would it be possible to connect more than one of these boards to a single arduino uno somehow? I just bought 3, and would just like to know if it would be possible to read temperatures from 3 x RTD's

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                              • CharlesC Offline
                                Charles
                                last edited by

                                @Roelof-Loots
                                Yes it's possible, each RTD board just need to have it own chip select pin (and led pin if you use it) all SPI pins can be shared (MOSI, MISO, SCLK), that the goal of SPI 😉

                                Take care your Arduino MUST be only 3V3 because RTD boards are 3V3 only, if your arduino is 5V you need level shifter and with 3 RTD boards it will be a real pain....

                                R 1 Reply Last reply Reply Quote
                                • R Offline
                                  Roelof Loots @Charles
                                  last edited by

                                  @Charles - Thx for that...im using a arduino uno, and looks like its got 3V3, so I should be able to do it correctly using a breadboard, else ill just get logic level converters.

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                                  • CharlesC Offline
                                    Charles
                                    last edited by

                                    @Roelof-Loots
                                    Take care, even if your Arduino Uno has a 3.3V pin available (fine to power RTD), all I/O need also to be full 3.3V (MOSI/MISO/CS/CLK) which may not the case. IT's better to have a full 3V3 Arduino (even at 8MHz)

                                    I'm using this one that have a switch to pass full board to 5V or 3V3 https://www.seeedstudio.com/Seeeduino-V4.2-p-2517.html or just find on ebay Arduino Pro Mini 3.3V USB 😉

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                                    • V Offline
                                      Vishi100
                                      last edited by

                                      Hi! I'm trying to interface MAX31865 (PT1000) to STM32F334 controller (Nucleo64) (Cortex M4) board. I used the Arduino codes from github and coded the STM32F3 controller. Both the sensor and the controller are tested & working fine. But when i read from MAX31865, I'm getting the maximum values in all the registers. Can i get plz get some help as to what might have gone wrong??

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                                      • F Offline
                                        Fernando Vinícius G. Magro
                                        last edited by

                                        Hi Charles, the IRQ (DRDY pin) of Max31865 need to be wired?
                                        I can presume that it can be useful to trigger an interrupt when a conversion is completed, but it is not mandatory. Can i left it unconnected ?

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                                        • CharlesC Offline
                                          Charles
                                          last edited by

                                          @Fernando-Vinícius-G-Magro
                                          The IRQ line should be wired only if you need an interrupt. So it's not mandatory don't worry you can left it unconnected.

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                                          • R Offline
                                            Rolando
                                            last edited by

                                            Hi Charles, what function R3 is supposed to do? And why 390Ω instead of 400Ω as recommended on Maxim datasheet? Thank you in advance.

                                            CharlesC 1 Reply Last reply Reply Quote
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