[plug] UPS & powerd

[Shackleton, Kevin]

The first question I'd ask is what's your cable?

I think basic UPS' usually work by asserting or not the handshaking lines.
Which are, in 25-pin mode: the "data terminal equipment" (DTE - the PC)
would normally assert pin 20 (DTR) and pin 4 (RTS), while the "data
communication equipment" (DCE - the modem) would assert pin 6 (DSR) and pin
5 (CTS).  Asserting means pulling to +12 V from the normal -12 V.  You can
look up the 9-pin equivalents in the back of electronics catalogues or
around the web.

If this is how it's done, then you would have to:
1) set one PC handshaking line high and one low ("assertlow RTS"?)
2) connect the correct DCE handshaking line (CTS, from the sound of your
config) to the one  DTE line via biassing resistors (1 K would do) and to
the other line via the relay contacts.

Are you lost?  Must be the way I explained it.

K.

> ----------
> From: 	Brian Tombleson[SMTP:Brian at ParadigmIT.com.au]
> Reply To: 	plug at plug.linux.org.au
> Sent: 	Friday, 1 September 2000 11:44
> To: 	plug at plug.linux.org.au
> Subject: 	[plug] UPS & powerd
> 
> Hi List,
> 
> I've read the UPS-HOW and all the doco with powerd (powerd-2.0-1.i386.rpm)
> for a "Liebert PowerSure" UPS I'm trying to get communicating with RedHat
> 6.2.
> 
> I've had a mail form their tech support saying essentially:
> 
> "pins 1 and 7 are low battery - pins 8 and 9 are on battery
> When the UPS goes on battery a relay closes and pins 8 and 9 are shorted
> together.
> When UPS battery is low, pins 1 and 7 short together. So, you need to
> monitor pins 8
> and 9 for a closed circuit. "
> 
> What I can't work out is how this information relates to powerd's config.
> 
> My current config :
> 
> delay 2
> serialline /dev/ttyS0
> monitor CTS
> failwhen high
> pollingstep 2
> asserthigh DTR
> 
> For some reason the daemon fails when I try turning on debug and I've
> tried
> specifying a logfile but nothing is ever written to it.
> 
> Anyone had any experience with this?
> 
> Any help would be greatly appreciated.
> 
> Regards,
> Brian Tombleson
> 
> 
> 
> 
>