Introduction: Separate 5v Supply to My Labjack U3 Hv.
The labjack u3 hv is the interface between my home and my custom built automation system. Anytime I need to reboot the pc, which is very rare, the labjack u3 hv power supply is cycled via the usb port.
For utmost reliability I need a separate 5v supply to my labjack. This is how I achieved it.
Step 1: Putting the House Into a Safe Mode.
Before I can shut down the pc to perform the modification, I have to do certain things to ensure the home automation system end devices don't go crazy.
First I switch the home power from solar to utility. Next I manually turn on the inverter that will power my living room air conditioner. Finally I turn off the breaker that powers the relay bank that controls door food/water, home loads inverter and a couple other devices.
Now I can safely power down the home automation pc.
Step 2: Modifying the Usb Cable.
Here I unplugged the usb cable from the labjack and used my utility knife to carefully cut away the jacket. Once the wires were exposed I cut the red wire that delivers 5v from the usb port. I put liquid tape on either end of the wire to avoid reconnecting.
Step 3: The New 5v.
The M4 atx power supply gives continuous power even if the pc is rebooted. From a previously established power supply terminal block, I ran a wire from the 5v terminal to a Vs terminal on the labjack u3 hv. This new 5v supply wire has a 3amp inline fuse.
Step 4: Completion.
I plugged in the modified usb cable into the labjack u3 hv and turned back on the automation pc. The power on leds were lit and the system fully operational again!
We have a be nice policy.
Please be positive and constructive.