[Nut-upsdev] Driver for Cyberpower PR2200

Arjen de Korte nut+devel at de-korte.org
Thu Apr 26 08:32:37 UTC 2007

> I captured the information before reading this, so I'll give you what I
> have for now, and if we need more data I'll capture some more.

We do. I forgot to mention that you need to activate the option 'Show hex'
in PortMon. Since this UPS uses a binary protocol, we can't see what's
happening without this.

One thing that we do know already, is that the current settings of the
cyberpower driver are wrong for your UPS. Yours expects that DTR is set
and RTS cleared, while the cyberpower driver sets both. The latter is
rather counter intuitive, since  most of the time, you'll want one of
either polarity to provide cable power. Otherwise, you need to rely on the
TX pin to provide power.

Since the combination RTS and DTR both set matches 'shutdown' in dumb (dry
contact) mode (genericups upstype=7 or upstype=22, which is used by other
cyberpower systems), I wouldn't be surprised at all if this causes your
UPS to shutdown after a while when running on battery. It is certainly
worthwhile to check if changing line 543 in cyberpower.c

 	ioctl(upsfd, TIOCMBIS, &rts_bit);
 	ioctl(upsfd, TIOCMBIC, &rts_bit);

solves the problem of unexpected shutdowns.

Best regards, Arjen

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