Home › Forums › Environmental Sensors › Hydros 21 CTD – Losing connection? [SOLVED] › Reply To: Hydros 21 CTD – Losing connection? [SOLVED]
2021-06-01 at 10:59 PM #15585
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):
Communication is hardwired to Mayfly digital pins 5 & 6, which enable use of the AltSoftSerial library.
Read more at our Notes on Arduino Streams and Software Serial.
Power to the RS485 to TTL Adapter comes from the Mayfly's switched 3.3V power.
Power to the sensor(s) comes from the Mayfly's switched 5V power supply, which can then be optionally boosted to 9V or 12V depending on the requirements of the sensor.