Re: Detect power redirection to ups
From: Nick Malik (nickmalik_at_hotmail.nospam.com)
Date: 10/19/04
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Date: Tue, 19 Oct 2004 14:34:56 GMT
Hello Stephane,
Your store owner would need to be CERTAIN that his register and printer are
supported, but will also be BETTER OFF if his UPS is also supported, because
you will have to write software to listen to each potentially different
message from a UPS.
So, call up your market base and find out what are the top one or two UPS
devices in use in the stores, and write support for them directly. I would
suggest using a "driver" software model, where your app simply registers an
event and you install a driver specific to the UPS to raise that event.
That way, you can write drivers for more UPS devices as time goes on.
You will want to get specs from the UPS manufacturers themselves. I do not
believe that there is a uniform protocol for communicating these messages.
Note: there are three hardware implications that may affect you:
(1) does the UPS actually send a data signal at all? The UPS may have no
port to send it on (smaller UPS devices, and those more than a few years
old, largely have no data message at all),
(2) what port will you receive the message on? Does your device have a type
A USB port? Most newer UPS devices, the ones with USB ports, have a type B
connection. Note that type A and type B are DIFFERENT. There are no
adapters for one to another, because the type A end, expected to appear on
computers, must provide electricity to the type B end. Therefore, your
device will need to have a type A port if you expect to communicate directly
with the USB port on the UPS.
(3) Most UPS devices have one and only one USB port. If that port is
already connected to the register (as it will be in some turn-key
installations), then you cannot connect to it. In a USB communication,
there is one A and one B. That's it. You cannot have two As and one B. It
would be irresponsible for you to tell a store owner to move the connection
from the register to your device. While you only need a second or two to
store everything, the register may need much longer than that. In this
configuration, you simply cannot succeed by directly connecting to the UPS.
In a traditional IT setting, a central computer would query individual
systems using SNMP (Simple Network Monitoring Protocol). Each system that
participates in SNMP would have a driver (usually called a MIB) that
responds to messages, gathers local events, and transmits them upstream.
The central system has the logic to send out messages when specific events
occur.
Therefore, if you were to follow standards, you would provide a MIB, for
your device, that runs on the register (you will need one for each major OS
of the registers). The MIB would query your device for status and send the
status messages to a registered listener (usually a network management
application like CA Unicenter or HP Openview). Also, the MIB would get
messages from the management application and relay them to your device.
That could be done by connecting another port from the register to your
device, or it can be done using some special interrupt sequence that the MIB
sends out by intercepting the data stream travelling over the printer port
(may not be easy to do the latter, but it costs less to manufacture the
device).
Your device can listen for the signals from the MIB, which can give
instructions like "backup now" and "systems initialization test" as relayed
from the management application.
That's the traditional way to do this. Sounds like this may be difficult in
your setting. I don't know. I'm not involved in the retail POS market.
There is another way to look at this, which is much simpler.
Let's stipulate that the power goes off and your device has a small battery
backup capability. The register will shut down. Three causes: (a) the
power went out to the register and no UPS was present... it simply quit.
(b) the register got a signal from a UPS or a MIB telling it to power down
immediately, (c) a frantic store clerk responds to the fact that she is
standing in a dark room with puzzled customers by shutting down the register
(as she was trained to do).
Once the register goes down, assuming you are still running on battery, the
register will stop sending data to the printer. If you have enough battery
to last for 15 minutes, you will last longer than the register would, which
means that the register will quit before you do. In this case, printing
will become idle.
If printing goes idle for more than 30 seconds, then you should simply save
everything, because there is a possibility that the power has gone off and
the register has gone offline.
That's as good a logic as you will likely get without installing software on
the register.
Good Luck,
--- Nick
"Stephane Belzile" <stephan.belzile@cgi.com> wrote in message
news:60e5a8a4.0410190543.7502c2b2@posting.google.com...
> Hi Nick,
>
> Our unit is designed to be placed between the cash register and the
> printer. It has to listen on the serial communication port of the cash
> register to record every transactions that are processed, record it
> into a database and send it to the printer with a unique identifier
> and a legal stamp. Since it will be used in thousands of stores all
> over the country, we will have to support a wide variety of cash
> registers models. Using regular expressions specific to each models,
> we can easily understand which information is sent to the printer
> through the serial port. We don't have to bother over which OS is used
> inside the cash register at all. The store manager will have to make
> sure his cash register and his printer are supported by our unit. If
> the store has a UPS, our unit will have to be connected to it as well
> as the cash register.
> Since the store owner won't be forced to use a UPS and because he can
> use wathever UPS unit he wants if he desires to have one, I can only
> rely on my own OS (Win CE or Xp Embedded) running in my Unit to notify
> my program that the UPS has started.
> The best solution for us would be as you said to put in our module our
> own UPS device or battery. In fact, we only need just a few seconds,
> not minutes or hours, to make sure we backup everything and shut down
> the process properly.
> Wether we use a own power backup system or the store owner's ups, we
> would like to intercept any notifications from the OS that the power
> had been lost.
>
> Stephane
>
>
> "Nick Malik" <nickmalik@hotmail.nospam.com> wrote in message
news:<iFRad.459378$8_6.264122@attbi_s04>...
> > Hello Stephane,
> >
> > First off, will the device be directly connected to the UPS device, or
just
> > to the cash register? If you are connected directly to the UPS, you can
be
> > notified by it. Otherwise, this is not a UPS question, this is a
question
> > of how you are notified by the OS.
> >
> > Secondly, is your device designed to connect to many different cash
> > registers, or a specific model and type of cash register? If so, you
may
> > know what version of the OS that the register is using, and what
hardware
> > features you can count on. Note that there is no reason to believe that
all
> > registers are actually notified by the OS. The fact that the OS *can*
be
> > notified does NOT mean that the register *will* be notified. These are
two
> > radically different things.
> >
> > http://support.microsoft.com/kb/q310752/
> >
> > Thirdly, can you put software on the register, or are you simply
connecting
> > to the serial port? If you are not installing software on the register,
> > then none of this matters, because there would be no application running
on
> > the pc to forward the message on to the serial port where you could
detect
> > it.
> >
> > It may make more sense for your device to use a simple Lion battery
backup
> > or USB solid state hard drive for data backup than for your device to
detect
> > if the UPS has switched power.
> >
> > --- Nick
> >
> > "Stephane Belzile" <stephan.belzile@cgi.com> wrote in message
> > news:60e5a8a4.0410120532.7b1cbef1@posting.google.com...
> > > Thank you Nick
> > >
> > > Actually, I'm developping a device that will be connected to the
> > > serial port of thousands of cash registers all over the country. In
> > > fact, I don't know which UPS unit will be in used if there is any.
> > > Since I'm dealing with very sensitive data, I don't want to loose
> > > anything in case of a power failure. I'm know the OS gets notified
> > > when the UPS unit start to deliver the power after a power failure
> > > (You confirmed that). And I'm pretty sure that the OS must send a
> > > message to all running application to let them know. My question is,
> > > how can I pick up this message when it happens or when the power comes
> > > back?
> > >
> > > "Nick Malik" <nickmalik@hotmail.nospam.com> wrote in message
> > news:<qKw9d.435291$8_6.368115@attbi_s04>...
> > > > Most UPS vendors support a method for communicating the status of
their
> > > > devices and the power supply. Most of them even have software that
they
> > > > sell or give away that will monitor your UPS device for power
failure,
> > so
> > > > that you can shut down a machine.
> > > >
> > > > For large networked systems, you'd use a MIB and SNMP, because the
> > larger
> > > > UPS devices can speak over a network. The smaller devices, for
personal
> > > > computers, often hook up over USB. For that, you will probably be
best
> > off
> > > > using the software that comes with the UPS. For example, if you
have an
> > APC
> > > > device, you would use Personal PowerChute, which is a free download
from
> > > > their web site www.apcc.com
> > > >
> > > > So, I ask, are you trying to do this for a server-sized UPS device
that
> > you
> > > > can hook to your network, or a smaller unit that you will hook to a
> > > > particular machine? If the former, SNMP is your method. If the
latter,
> > you
> > > > are doing either USB programming (proprietary, in all liklihood) or
you
> > can
> > > > configure the tools that come with the device to call your app.
> > > >
> > > > Good Luck,
> > > >
> > > > --- Nick
> > > >
> > > > "Stephane Belzile" <stephan.belzile@cgi.com> wrote in message
> > > > news:60e5a8a4.0410080518.422e0f8c@posting.google.com...
> > > > > Is there a way I can detect in vb.Net the power has switched to a
UPS
> > > > > unit in case of power failure?
> > > > >
> > > > > Thanks
- Next message: Robert Chapman: "Replication/Synchronization Component"
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- In reply to: Stephane Belzile: "Re: Detect power redirection to ups"
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