[Nut-upsuser] Re: Computer doesn't shutdown, only broadcasts a message to say low battery

[Philip Gaskell]

Hi,

I have been looking through the documentation of my UPS, it seems that
the serial port has two modes of operation. One seems to be "smart"ish
mode and the other dumb mode.

The PIN configuration for the Serial Port is:

PIN	MODE	ASSIGNEMENT DESCRIPTION
1	1	Low Battery (Open collector)
2	3	TxD
3	3	RxD
4	1	Remote Shutdown (5-12V); on battery
5	Both	Common
6	1	Remote Shutdown (Short to PIN5); any mode operation
7	1	Low Battery (Open Emitter)
8	1	AC Fail (Open emitter)
9	1	AC Fail (Open collector)

The pins for mode 2 are used by the software that came with the UPS, and 
there is no documentation to say what signal means what from them.

I have studied the source for the Liebert driver and it seems that for 
the particular model the driver was designed for the UPS connects RX and 
TX on Line failure, so if I were to change the pins that the data is 
read from and written to from RX and TX, whatever pins they are to pins 
8 and 9 then driver should then correctly identify when the UPS has lost 
mains power?

I know a little C, though I haven't done serial programming at all but I 
am willing to learn and abviously I am not familiar with the nut code, I 
only downloaded and compiled the software yesterday! Could someone give 
me a few pointers on how to implement these changes. In liebert.c I 
can't find anywhere that sets what ports to read and write from.

Cheers

Phil