We have a WSN-9791 with four WSN-3212s. All the 3212s have NI power supplies (not running off battery).
Three of the four 3212s give erratic readings. For example, the following was logged today from a room that should be around 70F:
17/10/2012 15:38:20 187.8
17/10/2012 15:39:20 148.9
17/10/2012 15:40:20 139.0
17/10/2012 15:41:20 -1548.9
17/10/2012 15:42:20 37.2
17/10/2012 15:43:20 158.8
17/10/2012 15:44:20 39.5
17/10/2012 15:45:20 111.5
17/10/2012 15:46:20 206.4
17/10/2012 15:47:20 -6.6
17/10/2012 15:48:20 188.6
17/10/2012 15:49:20 262.5
17/10/2012 15:50:20 74.1
17/10/2012 15:51:20 102.0
Location seems to play a part -- so far two different 3212s that are giving erratic readings have been very stable (with reasonable readings, too) when they sit on my desk, but go back to being erratic when moved elsewhere in the building. Additionally, one of the erratic nodes spends several days stable, then several days erratic, then back to stable. When a node is erratic, all four thermocouples on that node are erratic.
Thinking this might be a problem with electrical noise, I put one of the 3212s onto a UPS -- no difference. I've also changed the wireless channel used to a couple of different settings, without any change. I moved the 9791 to several different locations in the building, again without a difference. Thermocouple type settings have been triple checked.
Any ideas on how to further troubleshoot this?
