Seriously, "talk to your vendor." You can frequently get gear with
remote reporting, some of it will do dry contact or even talk RS232.
If you can not, a lot of it can be measured anyways.
If your gear doesn't "support" it, talk to generator service guys who
are well-thought-of in your area. I'd place good odds that they'll be
happy to outfit you with a computer-readable fuel level indicator,
oil pressure, remote test, etc., etc., though they may be smiling their
way to the bank and thanking you for all the custom work.
a lot of places just use a linux or BSD SFF/mini-ITX with a webcam
grabbing a jpeg/png every few seconds or once a minute on a cron job,
pointed at the controls/guages/meters. Just make sure the target area is
well-lit so the cam can see needles/guages etc.
Accessed by SSH (=scp/sftp/sshfs) and not running X or even a
web/ftpserver, its pretty hard to pervert it for nefarious means. Much
better than "IP webcams" which seem to be a magnet for google-hackers.
It's cheap and known-tech to most of us, but may require a shiny black
metal box (and a stainless bracket for the webcam) if the generator guys
don't like the idea at first. Great for monitoring electrical
breaker-boards, SAN hdd leds (using fast framerate grabs) or racks of
switches for pretty blinking lights (or the lack of).
Of course if you already have an old server box lying nearby, you're
laughing. Make sure to buy a well-supported webcam for your
kernel/distro to avoid madness. About 30-40$US will get a good one
usually, GIYF for supported models.
If you can get a RS232 fuel-gauge sender or enviro-sensors, you already
have a SSH-to-RS232 gateway
Some SCADA gear is extremely expensive and a can of worms in its own
I've solved this in several locations with Arduino (google is your friend)
boards. They're cheap ($40-$100/pop), are easily networked, and can be used
to send the required data back in a variety of formats (we have Nagios
monitoring them, checking every X minutes). This, of course, is no
replacement for running the genset every so often to verify it actually