UPS Tab & wiring?

[Guest]

First time posting to the newsgroups - sorry if this is not the correct group.

I'm interested in using the built-in UPS support in Windows Media Center for
an in-car PC. I see I can select a 'generic' manufacturer, and 'custom'
model and select my serial port to communicate on (I'm using Com1).

When I attempt to configure the interface I get three options to enable,
each one having negative/positive as a selection. The three options are:
Power Fail/On Battery, Low Battery, UPS Shutdown.

I'm assuming I can just use the power fail/on battery method, then configure
the appropriate number of minutes on battery before critical alarm and have
the computer hibernate or shutdown. (so that's kindof my first question-
should that work as expected?)

Second, and maybe a more simple question - is what method of communication
is happening here? What do I need to trigger to get this to happen?
DTR/DSR/RTS/CTS/RI etc? If someone can put it in simple terms that would be
best (ie, connect (signal ground - pin5 on db9) and connect to (DTR - pin 4
on db9) to trigger the positive connection for power fail/on battery.

I'm planning on connecting a 12v relay to the ignition switch to close/open
the loop for whatever pin(s) I need to so hopefully this will be a simple
connection.

 

[Paul Randall]

Hi, Jeff,
I'm not sure, but there may be hardware groups that have more knowledgable
people on this subject. I have some cheap UPSs. They have a small built-in
battery and an inverter so they can supply 120VAC for a short time. They
normally just pass through 120VAC from the wall outlet to the UPS's outlets;
when the normal power fails, the UPS's inverter starts and its 120VAC output
is connected to the outlets. A completely different device is the 120VAC
inverter you can purchase relatively cheaply that can supply power to a
computer. You plug it in, turn it on, and you have 120VAC available from
its outlets. A UPS does not work this way. You can't just turn it on and
get 120VAC from its internal battery. I suppose this may not be true for
all UPSs, but it is for the two that I have used.

Maybe you should post the brand and complete model number of the UPS you
intend to use. You might also go to the manufacturer's web site and
download the manual. It should give you wiring diagrams and info about the
software included with the UPS for monitoring it.

-Paul Randall

 

[Guest]

Hi Paul.

Thanks for the reply. Sorry if I was not clear with my original post. Let
me post a little more details about what I'm trying to accomplish.

I have a in-car computer that runs directly on 12volts and is wired directly
to my car battery and thus can be powered on even while the engine is not
running. I'd like Windows to power down after 30 minutes of running on
'battery' power. I understand using power management I can have my system
standby/ hibernate/ shutdown if idle via the power options properties in the
control panel, however, I'm looking for a method to force shutdown after a
period of time. Since windows has support for generic UPS's and it would be
fairly simple for me to wire in a relay sitting next to the computer that
activates when the ignition is on, allowing me to open/close a circuit. I'm
interested in knowing what pins I need to close on a serial port to tell
windows my computer is 'running on battery power'. So there is no 3rd party
software, no ups manual to consult, etc. It's simply a matter of what
signaling does windows use for it's generic ups support.

I see that Windows has built-in support for a 'generic' UPS and am trying
to understand how that signaling is supported.

 

[Paul Randall]

Hi, Jeff
Here is a quote from
http://support.microsoft.com/kb/234966
<quote>
UPS functionality has been integrated into the Power Options tool in Control
Panel. Most UPS devices have a either a serial or Universal Serial Bus (USB)
connection to a computer.

USB
A UPS that is connected using a USB cable is represented as a battery in
Windows 2000 and is configured using the Alarms and Power Meter tabs in the
Power Options tool. In this case the UPS presents itself as a Human Input
Device (HID) compliant device and Windows 2000 automatically installs the
necessary drivers.

Serial/PnP
A UPS that is connected using a serial cable is configured using the UPS tab
in the Power Options tool. Windows 2000 may or may not recognize a serial
PnP UPS.
<end quote>

I could be wrong, but to me, this means that the UPS sends messages in the
form of character strings and responds to similar strings, from the
computer, requesting information. In other words, its plain old RS232
communication, not status of voltage on certain pins on the 9-pin connector.
You may be able to find a description of the protocol at various UPS
vendor's sites or at MSDN.

There are programmable controllers that might be able to impliment the
protocol.
http://shop3.outpost.com/product/5321468?site=sr:SEARCH:MAIN_RSLT_PG

-Paul Randall

 

[Guest]

Hi Paul.

Again, thanks for your reply. I took a look at the KB article you linked.
Yes, that is the control panel applet I am referring to. And I understand it
may or may not be there if I am using a USB UPS, but it does also mention
exactly what I am referring to. That there is support for a 'Generic' UPS.
I understand that I may need to add additional hardware to make this happen,
but I'd like to confirm that before I go that route.

Let me ask my question in a different light so that you might see the
information I am looking for.

Let's say I am developing my own hardware device, a battery backup, and I
don't want to write my own device driver, nor my own software. I plan to
have users use the buit-in UPS functionality to control the unit. What is
the Windows Operating System monitoring with its built-in functionality to
recognize these events? If you say I may need to comunicate over the serial
connection, that's not what I'm looking for and if you don't know, that's
fine, but I'm looking for a more definite answer before I pick my path to
continue. I'd like specifics, such as I need to turn DTR high/low to make
the signal, or I need to send an ASCII string such as "ON BATTERY" at
9600,8,n,1 etc..

 

[Paul Randall]

As you may have guessed, I don't know. I'm just throwing out possibilities
based on stuff I've read and a general knowledge of RS232 communication I
used back in the '80s & '90s.

I'd suggest searching manufacturer's web sites for the rs232 wiring diagram.
One resource/list:
http://www.jetcafe.org/~npc/doc/ups-faq.html

-Paul Randall