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Hydros 21 CTD – Losing connection? [SOLVED]

Home Forums Environmental Sensors Hydros 21 CTD – Losing connection? [SOLVED]

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    • #15581
      James_NZ
      Participant

      Hi all,

      I am testing a Mayfly setup with a HYDROS 21 CTD and a Yosemitech 511-A turbidity sensor. The Turbidity sensor is working well, but the CTD seems to intermittently dropping in and out (see attached MMW plots).

      Any thoughts on what might cause this? I have set the CTD address to channel 1 as per instructions. I did notice that the ‘sdi12_address_change.ino’ script went haywire until I removed the Modbus WingShield, so I wonder if the Y511-A is interfering with the CTD signal? The Y511-A is set to address 0x01 as per factory settings.

      Thanks in advance for your help.

      James

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    • #15584
      Shannon Hicks
      Moderator

      Does your Modbus wingshield do any level shifting of the CTD’s SDI-12 data line?  Is there anything on the wingshield tied to whatever Mayfly pin you’re using for the data line (I’m assuming D7)?

    • #15585
      James_NZ
      Participant

      Hi Shannon,

      Yes I am on D7 for the CTD. I am using the default pins for the mayfly modbus wing (https://github.com/EnviroDIY/Mayfly-Modbus-Wing/tree/master/Modbus-Mayfly_WingShield):

    • #15586
      James_NZ
      Participant

      I have switched my pin for the HYDROS 21 CTD from D7 to D11, but I seem to be having the same issue.  It’s worth noting that I don’t get -9999 values when plugged into my computer.  Could it have something to do with power?

      My code is below.

       

    • #15587
      James_NZ
      Participant

      I had a lightbulb moment today that seems to have fixed my problem.  I switched the 3.3v jumper to 5v.  Success!!  I guess it was brown-out.

      James

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