Hardware Installation Instructions

[sjaffe1]

I bought an HA7e and some temp sensors a few years ago but never got around to installing them. I'd like to revisit the effort but I've since used all of my comm ports. I figure it would be cheaper to buy a USB adapter than a PCI comm card and I was looking at the DS9490R.

Is this the best USB adapter to buy? Also, does anyone have any hardware installation instructions (based on their installation with HS). I seem to remember that longer runs require a 5volt power supply to be inline with the sensor.

Any help would be appreciated.

Seth Jaffe

[Michael McSharry]

I think the DS9490 is the only choice and it will work fine. You can have 2, 3 or 4 wires in your run. If only temperature sensors then 2 is fine. If you have humidity or other DS2438-based devices then you will want a 12V line. A 5V line can also be used, but not needed due to wire length. You may find sometimes you need 5V at one of the 1-wire interfaces. If you do inlcude it then you can use it with the temperature sensors too.

There have been many discussions on 1-wire topology this on this message board. Perhaps a seach on topology will find some of them. There is much to be said about out. There is theory, but go guarantees as there is some art to it just as there is some art to RF.

You are generally better to have a single line that snakes everywhere rather than a homerun star topology. Each branch introduces reflections and these reflections may cancel the digital communications.