Post by thread:[OT]: Help Wanted, UPS Interface

G'day, I'm trying to figure out the interface pinout for a uninteruptible power supply (UPS) that I have. The unit came with no documentation, and no interface cable, and I suspect that the cable may require some pin remapping anyway. If you are willing to help, I've drafted a schematic of the circuit in the UPS attached to the DB9. I've not gone beyond the optocouplers; I got rapidly lost. I've also taken a few snapshots of the PCB. <http://quozl.netrek.org/p600v/> (220k of images) The UPS is straight analog; there are no digital components on the PCB, no crystals, no microcontrollers (sadly), just bog standard things like LM339's. I suspect therefore that the signalling from the UPS to the PC is just "online" and "low battery", via modem status lines. But there's a twist; there is an optocoupler facing the other direction. I can't figure out what function it has. -- James Cameron spam_OUTquozlTakeThisOuTus.netrek.org http://quozl.netrek.org/ -- http://www.piclist.com hint: The list server can filter out subtopics (like ads or off topics) for you. See http://www.piclist.com/#topics

Hi, One of my UPS's is also pritty simple. I don't know te exact meaning of the signal lines but it's RS232 'compatible'. This means you can connect it to the PC using standard RS232 interface. Wy don't you monitor the status lines of the UPS or connect the status lines to some leds. Just load the UPS and see when the UPS goes offline and what happens to the status lines (low power etc). Check out the Linux docs the also have some really good docs about UPS, I think there is a 'standard' for it. Also check out the brand and just call them for the docs. Ries -- http://www.piclist.com hint: The list server can filter out subtopics (like ads or off topics) for you. See http://www.piclist.com/#topics

James, I faced the same problem with a surplus UPS I got. Take a look at the Linux UPS Howto on metalab.unc.edu/mdw/HOWTO/UPS-HOWTO.html . They have a section on different interface types. Although my UPS was not listed, given a little testing and looking at the different diagrams, I was able to come up with what it was doing pretty quickly. The HOWTO also has a section on cable building and of course how to get it working under linux. John {Quote hidden}> > I'm trying to figure out the interface pinout for a uninteruptible > power supply (UPS) that I have. The unit came with no documentation, > and no interface cable, and I suspect that the cable may require some > pin remapping anyway. > > If you are willing to help, I've drafted a schematic of the circuit in > the UPS attached to the DB9. I've not gone beyond the optocouplers; I > got rapidly lost. I've also taken a few snapshots of the PCB. > > <http://quozl.netrek.org/p600v/> (220k of images) > > The UPS is straight analog; there are no digital components on the > PCB, no crystals, no microcontrollers (sadly), just bog standard > things like LM339's. I suspect therefore that the signalling from the > UPS to the PC is just "online" and "low battery", via modem status > lines. But there's a twist; there is an optocoupler facing the other > direction. I can't figure out what function it has. > -- http://www.piclist.com hint: The list server can filter out subtopics (like ads or off topics) for you. See http://www.piclist.com/#topics

James, There's an UPS howto on the linux docs, there's a lot of info on pinouts, maybe it can help. >G'day, > >I'm trying to figure out the interface pinout for a uninteruptible >power supply (UPS) that I have. The unit came with no documentation, >and no interface cable, and I suspect that the cable may require some >pin remapping anyway. ----------------------------------- Ricardo Seixas .....rseixasKILLspam@spam@pobox.com ----------------------------------- -- http://www.piclist.com hint: The list server can filter out subtopics (like ads or off topics) for you. See http://www.piclist.com/#topics

> -----Original Message----- > From: Oliver Broad [SMTP:obroadKILLspamTELINCO.CO.UK] > Sent: Saturday, July 22, 2000 5:19 PM > To: .....PICLISTKILLspam.....MITVMA.MIT.EDU > Subject: Re: [OT]: Help Wanted, UPS Interface > > The one in the other direction is probably remote shutdown. Where a UPS is > used unattended it is common to have software to force a controlled > shutdown > after a time limit to protect the battery. > > That would make sense. There is an RC filter on the input with a very high time constant. Presumably to avoid any interference that could appear on the RS232 line from immediately shutting down the UPS. What is a little suspicious is that there is nothing to prevent the electroylitic cap having a reverse polarity applied from the RS232 lines, although there is a diode which must be there to either stop BE breakdown of the transistor and/or to increase the effective delay time of the 890K/47uF combination. Regards Mike {Quote hidden}> ----- Original Message ----- > From: James Cameron <EraseMEquozlspam_OUTTakeThisOuTUS.NETREK.ORG> > To: <PICLISTspam_OUTMITVMA.MIT.EDU> > Sent: Saturday, July 22, 2000 1:30 PM > Subject: [OT]: Help Wanted, UPS Interface > > > > > The UPS is straight analog; there are no digital components on the > > PCB, no crystals, no microcontrollers (sadly), just bog standard > > things like LM339's. I suspect therefore that the signalling from the > > UPS to the PC is just "online" and "low battery", via modem status > > lines. But there's a twist; there is an optocoupler facing the other > > direction. I can't figure out what function it has. > > > > -- > > James Cameron @spam@quozlKILLspamus.netrek.org http://quozl.netrek.org/ > > > > -- > > http://www.piclist.com hint: The list server can filter out subtopics > > (like ads or off topics) for you. See http://www.piclist.com/#topics > > > > -- > http://www.piclist.com hint: The list server can filter out subtopics > (like ads or off topics) for you. See http://www.piclist.com/#topics -- http://www.piclist.com hint: To leave the PICList KILLspampiclist-unsubscribe-requestKILLspammitvma.mit.edu>

The standard controls for a dunb UPS are: power fail: active low ups -> computer battery fail: active low ups -> computer shutdown: active high computer -> ups The shutdown command hopefully works only when the UPS is running on battery otherwise you will (may) have serious setup problems with a straight cable (peripheral probing during boot can shutdown). Check with a desk lamp and a PSU (or 4.5V battery + 1k resistor). You can check the PSU outputs with a DVM set for diode range. Then make a cable (you may also refer to the Linux UPS-Howto which is way out of date imho but contains useful clues and doubtful circuits - beware !). Peter -- http://www.piclist.com hint: To leave the PICList RemoveMEpiclist-unsubscribe-requestTakeThisOuTmitvma.mit.edu>