Advanced GPO's on new MX2 models

dmt17 · Post by **dmt17** » Mon Jul 28, 2003 5:27 pm

I ran into this article on the web somewhere and have some questions about the new unit with the improved GPO's. Figured I would throw some questions out there. The integration of the Dallas Temperature Sensors built into the MX2 is a great improvement on the unit. I ordered the new model as soon as I was done with the article in order to take advantage of the new features. My question is about the temperature sensors that use the WOL cables, it says you are only limited to about 3 feet. I was thinking about monitoring the temp. outside my house also if thats possible. It also states that you can have up to 32 sensors hooked up to the unit!? Was I reading it wrong? Or did the writer mean something else. Well if anyone wants to enlighten me on these topics your more than welcome.

Thanks..........Here's the link to the article http://www.gruntville.com/reviews/video ... /index.php

Post by **Henry** » Mon Jul 28, 2003 6:04 pm

There are 4 physical temp probe headers, but they all use the same data line and the limit of the interface is 32... so all you do is keep attaching the probes to the same wire. I'll get you a maximum distance tomorrow.

dmt17 · Post by **dmt17** » Mon Jul 28, 2003 6:23 pm

So I guess you can daisy chain the probes somehow. Where can I get a cable like that? Thanks, you cleared up a few things.

Post by **linear** » Tue Jul 29, 2003 8:52 am

I'd recommend getting a WOL cable (about a buck at a PC shop) and removing the connector. It's an IDC (insulation displacement connector), so with a bit of fiddling, you can mate it to your own wire. I might suggest using category 5 wire since it's readily available in arbitrary lengths.

Miles · Post by **Miles** » Tue Jul 29, 2003 9:35 am

Hello...

Our official stance on this topic is that we tested 4 probes at 1 meter each and it worked perfectly, however we are very confident that it can handle greater distances but we cannot guarantee anything...since we have not tested at greater distances we leave this to you....

Give it a try and let us know how you make out...

dmt17 · Post by **dmt17** » Tue Jul 29, 2003 9:45 am

So I can typically make my own WOL cables for the temp probes if I can get me hands on the WOL connectors. I can pretty much solder the Dallas Probes on in that case, just one connector to interface with the MX2 unit. I'm still waiting to find out what the max length of the Dallas cables can be though. The only reason I ask is because I want to monitor the temp outside my house.

Paradigm · Post by **Paradigm** » Tue Jul 29, 2003 3:04 pm

The maximum distance of the wire is a little bit of a tricky question. It depends on the 1-wire driver. For those who want the really technical end of things, the best references are at http://www.maxim-ic.com/an_prodline2.cfm/prodline/21. Specifically you should probably look at one that isn't listed there:

http://pdfserv.maxim-ic.com/an/en/app132.pdf

and also

http://pdfserv.maxim-ic.com/an/en/app148.pdf

The long and the short of it is that with the controller that we use, only a total of 25m (about 82ft) is reccommended. However since we haven't tested it, we can't guarantee it.

And the better the cable you use, the longer it should go. One cable you could try using is cat3 or better cable (eg cat5 ethernet cable). Cat5 will have 5 extra unused wires but it is a good quality and should help with distance.

dmt17 · Post by **dmt17** » Thu Jul 31, 2003 11:26 am

Thanks for all the help. My unit should arrive today and as for the Dallas probes who knows when they'll arrive. As soon as I get everything up and running I'll let you guys know how it does on a long cable. I dont plan on having a long run either only about 10 feet, I figure I'll be able to get some accurate results from it.

DT

Miles · Post by **Miles** » Tue Aug 05, 2003 12:18 pm

Can't wait to see the results...!!