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Plex Knock Monitor V2 disconnecting

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Hi all,

Has anyone else encountered an issue with their Plex Knock Monitor V2 where when it's connected to the laptop and Plex software, the device randomly loses power and switches off?

I've noticed when I'm doing ramp runs, as the car gets up into high rpm the device just loses power and switches off. I tried disconnecting the inductive lead to see if it was some sort of interference issue but still does the same thing.

Its obviously an issue when it's running off the laptop power because when I power it externally it's fine but then I can't get any data through to the software.

Any help greatly appreciated!


USB plug? Try a different port / cable.

I've had this problem with mine caused by electrical interference. One time in particular I was having a lot of problems when I had the Plex unit sitting on the sheet metal floor of a tubular frame/sheet metal race car. Raising it off the floor with a towel solved the problem. You could also try keeping the Plex unit outside of the car if you're operating in a dyno bay and just run a USB extension cable into the car for your laptop

I am considering of buying Plex knock , how effective it is in detecting knock ?

I think it is fantastic. One feature I really like is the graphing of knock level noise vs RPM which can allow you to identify trace knock before it is audible.

The new V3 model is about to be released, I'll be getting one for sure

My plex V2 does this consistanty. I'm now powering it externally and it never drops out. Connecting to vehicle battery w/ fused positive.

Tried: Another usb cable x 3, different laptop, dyno PC. All lose connectivity via power through USB

From my computer IT support experience: try a "powered USB hub". That might provide solid power to the Plex v2 unit, and clear up your issue.

Ben how do you go about powering it externally whist retaining the ability to connect it to the laptop for data logging?

AJ thanks for that I'll give it a try!

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