Reply To: Reading -9999 on all Sensors

Both of those sensor models ship from their manufacturers with their SDI12 address set to ‘0’ (zero).  In order for the Hydros21 sensor to work with the Mayfly logger in SDI12 mode, you MUST change the address of the sensor to anything other than zero (otherwise the sensors is in TTL output and not SDI12).  It’s okay for the ClariVue sensor to remain at channel 0, but your logging sketch should agree with whatever you’ve set it to, and your sketch says 2, so you’ll need to use the address-changing sketch to set the channels.  Note that you can’t connect both new sensors at the same time when setting the channel.  Only connect one sensor to the Mayfly when doing the address changing procedure.   Once you’ve got one sensor connected, the sketch will cycle though all 62 possible channels.  If it’s not stopping on zero (or maybe another channel if you’ve been able to successfully change the channel earlier), then that means your logger doesn’t hear anything from the sensor.  If that’s the case, then your wiring to the Mayfly may be wrong or something else.  Are you supplying 12v to the ClariVue sensor using a screw terminal board (either directly from the Mayfly’s onboard 12v option or the external 12-v boost screw terminal board)?  The Hydros21 works fine at 3.3v or 5v or 12v.   If you’re using the 3.5mm stereo plug option, make sure it’s plugged firmly into the jack on the Grove adapter board.  If you’re using bare wires, make sure you’ve got the 3 wires from the sensor connected to the proper screw terminals (Ground, V+, and S2).