we-re using your Fathom-X interface on our MATE explorer class rov.
The modules link fine after being off for a while, but when we power cycle the robot, the modules don’t want to re-link.
We have found that if we just power the ROV down, we need to wait a full two minutes before we can power it up and get a good link (this is regardless of whether we power down the topside link or not)
We can tell if the ROV is going to link, because when we power it on. If there is an initial green link flash, the modules will connect. If the green Link LED does not flash, then it will not link.
Note: the ROV is powered by 48V and we use this power pair for the Fathom X link.
48V is down converted to 12v on the robot, and this is used to power the fathom X.
We checked and the 12V drops to a few mV when we power down, but the 48V tends to drop to a few volts very quickly and then slowly ramps down to oV over several minutes.
We did some experiments and found that if we discharge the 48V line(at the fathom X) after powering down, then the modules link up right away without having to wait the two minutes.
So it seems like the residual voltage on the link lines is preventing the modules from re-linking on power-up
Is this possible?
We are considering adding a high load resistance to the 48V line to drain the caps in the voltage regulators more quickly, but since the supply is a high voltage, we can’t go too low with the resitance, so it may not be that effective.
Do you have any other suggestions.