You need to install the sys-power/nut package. If your UPS has an USB interface, make sure you install it with the usb flag.
Once installed, visit http://www.networkupstools.org/ and go to the Compatibility List. There you can filter your UPS Manufacturer to check the NUT driver you will be using. If your Manufacturer appears but your Device Model doesn't you can try to use the same driver as any other model like the one you have. In my case I have a PowerWalker VI 650 LCD that doesn't appear on the list, but since other models of PowerWalker are using the blazer_ser and blazer_usb drivers, I'm going to use the blazer_usb driver for this one.
Edit the configuration file /etc/nut/ups.conf to add the configuration of your UPS, mine is as follows:
[PowerWalker] driver = blazer_usb port = auto desc = "PowerWalker VI 650" norating novendor
Then you can try if NUT can find your UPS by running the upsdrvctl command:
# upsdrvctl start Network UPS Tools - UPS driver controller 2.6.5 Network UPS Tools - Megatec/Q1 protocol USB driver 0.09 (2.6.5) Supported UPS detected with mustek protocol Vendor information unavailable No values provided for battery high/low voltages in ups.conf Using 'guestimation' (low: 10.400000, high: 13.000000)! Battery runtime will not be calculated (runtimecal not set)If the command runs without errors, you have your UPS successfully detected by NUT. Some drivers as the blazer_usb, will require extra commands to provide the battery charge and autonomy values.
Last step is configure an administration user name in /etc/nut/upsd.user. Once that is done, you can start the daemon and if you don't get any error, add it also to your runlevel.
# /etc/init.d/upsd start * Starting upsd ... fopen /var/lib/nut/upsd.pid: No such file or directory listening on 127.0.0.1 port 3493 not listening on ::1 port 3493 Connected to UPS [PowerWalker]: blazer_usb-PowerWalker # rc-update add upsd * service upsd added to runlevel default
Once we have the daemon started, we can monitor the UPS with the upsc command. This command requires the name we gave the UPS in the /etc/nut/ups.conf file and will give us all the information about our newly-installed UPS:
# upsc PowerWalker battery.charge: 100 battery.voltage: 13.50 battery.voltage.high: 13.00 battery.voltage.low: 10.40 battery.voltage.nominal: 12.0 device.type: ups driver.name: blazer_usb driver.parameter.pollinterval: 2 driver.parameter.port: auto driver.version: 2.6.5 driver.version.internal: 0.09 input.current.nominal: 2.0 input.frequency: 50.1 input.frequency.nominal: 50 input.voltage: 231.5 input.voltage.fault: 231.5 input.voltage.nominal: 230 output.voltage: 231.5 ups.beeper.status: disabled ups.delay.shutdown: 30 ups.delay.start: 180 ups.load: 9 ups.productid: 5161 ups.status: OL ups.type: offline / line interactive ups.vendorid: 0665