Problem Connecting MK3 sonar via ROV power


I have got an MK3 sonar from Tritech which was RS-485 configured. The data was not transmitting while running through the ROV Power Supply Enclosure for OTPS, however, it was running perfectly fine while I bypass the Power Supply Enclosure and gave in a direct 12Vdc supply which the electronics needed.

Any ideas on why is this happening? Could it be a power interference from the Power Supply Enclosure? Connections are as attached.

Hi @Aquila,

The Tritech Micron Sonar Datasheet seems to suggest it should operate with a power supply providing anywhere from 12-48V.

The main suggestions I can think of are:

  • while the power is off, use a multimeter to do a continuity/resistance check on each wire in the pair that you’re trying to send the RS485 signal through (which seems like it should be the orange pair according to the OTPS tether product page)
  • turn on the vehicle and confirm that the power output on the ROV side is within the specified range for the sonar (it should be 15V, according to our technical details)
  • if possible, use an oscilloscope to measure the signal across the sonar communication wires at the topside, to see whether there is much electrical noise compared to when you’re using your setup that bypasses the ROV Power Supply Enclosure
    • note this may need to be done as a difference measurement between two probes, as the negative clip of oscilloscope probes is often connected to earth