I have just bought a 24v power supply for my G42 which has an isolated output. I guess this would be the same as using a 24v battery as that would also be isolated. This means that the only reference between the power supply 0v and the computer 0v line would be via the USB connection.

The question is, it sufficient to do this, or should the 0v of the computer and any power supplies used for mounts, cameras and focusers etc be managed in a better way.

For example should the 0v points of all the external power supplies be connected together and then connected to the computer 0v in a more positive way?

I would be interested to hear any comments.

Peter

Hi Peter!

I seem to remember that many manufacturers of USB interface IC's recommend that the shield on the USB cable is not DC coupled to chassis ground. They recommend AC grounding via capacitors. Using an ohm-meter indicates that this is the case with the PS2 as well. So this indicates that there should be no direct connection between the battery 0 V( or power supply 0 V) and the chassis ie. the shield of the RA/DEC motor cable going to the G42+ chassis. However, using the ohm-meter I see that there is about 11 ohms between the chassis of the mount and the battery 0 V terminal.

This means that it is hard for me to recommend the proper grounding procedure for the mount. I hope the electrical designer of the PS2 can chime in and shed some light on this question.

However, I have not experienced any problems using a floating power supply or battery on the G42+.

Best regards

Oivind Tangen

Hi Oivind

Thanks for that. I am now running isolated and it works just fine.

Peter