shark100mon

Shark 100 Power Meter Monitoring and Display

The Shark 100 power meter is network-connected but does not have a web server. It does, however, provide a TCP modbus interface.

This is a simple go server that reads power draw, voltage, and frequency from the Shark and either logs it to the console or makes it available via a webserver running on (default) port 8081.

Note that this version displays the voltage across both hot lines, as I'm using it in a 240V application. You can change the registers it reads to show different values. (They're listed in the manual for the meter).

The IP address of the shark meter is hard-coded. If you find this program useful and would like me to generalize that a little, let me know. Otherwise, I assume I'm either the only one using it, or that anyone else is using it as reference code for hacking their own thing up.

The included 'powermon.html' web page has a bit of javascript that auto-refreshes from the Go web server. It's formatted to fit nicely on a horizontally-oriented iPad.

Building

Either use the normal go techniques, or just build in directory:

go build main.go
mv main powermon

Web server use:

nohup ./powermon >& /dev/null &

Web page

Interactive use:

./powermon -i

Output

dga@server:~$ ./powermon -i
Watts: 19736  volts: 220.41   frequency: 59.9833 hz
Watts: 19696  volts: 220.39   frequency: 59.9826 hz
Watts: 19682  volts: 220.37   frequency: 59.9832 hz