HA7Net + DS1820 gives 85 degrees

Post by **Digit** » Tue Nov 20, 2007 10:09 pm

Hi,

Strange things always seem to happen when i'm using 1-wire...
I added an extra Temperature sensor to my HA7Net yesterday, to measure the temperatures of the water used for heating.
But i get some strange results. Here's what i mean:

2007-11-20 20:51:45.000 1WT3.TEMP 47.375000
2007-11-20 20:51:31.000 1WT3.TEMP 47.625000
2007-11-20 20:51:16.000 1WT3.TEMP 47.937500
2007-11-20 20:51:00.000 1WT3.TEMP 85.000000 <--
2007-11-20 20:50:46.000 1WT3.TEMP 48.187500
2007-11-20 20:50:15.000 1WT3.TEMP 85.000000 <--
2007-11-20 20:50:00.000 1WT3.TEMP 48.687500
2007-11-20 20:49:45.000 1WT3.TEMP 48.937500
2007-11-20 20:49:30.000 1WT3.TEMP 85.000000 <--
2007-11-20 20:49:16.000 1WT3.TEMP 49.187500
2007-11-20 20:49:00.000 1WT3.TEMP 49.250000
2007-11-20 20:48:46.000 1WT3.TEMP 49.187500
2007-11-20 20:48:30.000 1WT3.TEMP 49.750000
2007-11-20 20:48:15.000 1WT3.TEMP 49.812500
2007-11-20 20:48:00.000 1WT3.TEMP 85.000000 <--
2007-11-20 20:47:45.000 1WT3.TEMP 50.625000
2007-11-20 20:47:30.000 1WT3.TEMP 85.000000 <--
2007-11-20 20:47:15.000 1WT3.TEMP 51.125000
2007-11-20 20:47:00.000 1WT3.TEMP 51.062500
2007-11-20 20:46:46.000 1WT3.TEMP 51.312500
2007-11-20 20:46:30.000 1WT3.TEMP 51.812500
2007-11-20 20:46:00.000 1WT3.TEMP 85.000000 <--
2007-11-20 20:45:45.000 1WT3.TEMP 53.375000
2007-11-20 20:45:30.000 1WT3.TEMP 53.500000
2007-11-20 20:45:16.000 1WT3.TEMP 53.625000
2007-11-20 20:45:01.000 1WT3.TEMP 53.812500
2007-11-20 20:44:46.000 1WT3.TEMP 53.687500
2007-11-20 20:44:30.000 1WT3.TEMP 53.437500
2007-11-20 20:44:15.000 1WT3.TEMP 85.000000 <--

I keep getting these odd 85 degrees readings.
I'm using a DS1820, power supplied by the Ha7Net, checked at 4.98 V, using firmware version 1.0.0.16.
Even the web-interface gives me the "85" readings, so i'm not doing anything wrong in my software.

What could be wrong here?

Robert.

Post by **Bwired** » Tue Nov 20, 2007 10:48 pm

Did you try resetting restart the system and scan the line again?

Post by **Digit** » Tue Nov 20, 2007 10:56 pm

Yep. No change in behaviour.

Post by **Kroonen** » Tue Nov 20, 2007 10:58 pm

Mostley if te time-out is to short (1-wire bus is long) he reads nothing and displays it as 85 degrees.

Post by **Digit** » Tue Nov 20, 2007 11:04 pm

Cable is ca. 4m, UTP. And i don't have influence in how long the HA7Net waits for the conversion. As you can see above i use the high level ReadTemperature command.

Post by **Bwired** » Tue Nov 20, 2007 11:24 pm

Try switching the sensors. I have similar problems once I change the setting I need to restart, rescan the wire several times before I get readings of every device on the wire.

Post by **Digit** » Tue Nov 20, 2007 11:42 pm

Ok, I'll do that.
There were more sensors planned here, i'll add those too (total will be 4), so i can see if all of the sensors are having these problems or not.

I'll keep you informed.

Robert.