Connecting Temp sensor to Omni Pro II

[kurtmccaslin]

I am working on designing my Omni Pro system and have come up with a question...
 
The manual for the Model 17A00 Expansion enclosure says "The Expansion Enclosure may be used to connect up to 16 Temperature sensors"
 
However, when I look at the Manual for the Model 31A00-7 Expanded range temperature sensor, it says  "The Model 31A00-7 can not be connected to a zone on an expansion enclosure (i.e. Model 17A00)"
 
 
It seems conflicting.   Does this mean that certain temp sensors are compatible with the 17A00 and others are not?    Or is it a typo in one of the manuals?

 

[kurtmccaslin]

I found my answer in the HAI knowledge base:
 
These temperatures sensors convert temperature to frequency – the higher the temperature, the higher the frequency. The temperature to frequency conversion for the extended range sensors produces much higher frequencies than the standard sensors.
 
When connected to any zone on the main controller or hardwire expander (10A06-1), the frequencies of temperatures above 100 (up to 120) degrees are not a concern. When connected to a zone on an expansion enclosure (17A00-X), the frequencies for extended range sensor temperatures above 100 degrees cannot be measured accurately, which results in inaccurate readings being reported back to the controller. With that in mind, your limitations are:
 
a. The 31A00-1 and 31A00-2 can reliably measure 0-120 F on any zone.
b. The 31A00-7 and 31A00-8 can reliably measure -40-120 F on zones on the main board hardwire expanders, but only -40~100 F on an expansion enclosure.
 
Depending on your temperature range requirements you can choose which works best for you.

 

[ano]

Basically standard (older) temp sensors convert temperature to a voltage, and the panel zones or an expansion enclosure zone can measure this voltage and turn it back into a temperature reading.
 
The extended temp sensors are newer and were supported with a firmware update to the panel. They take a temperature and convert it to a low frequency tone that varies with the temperature which the panel zones can decode, but its not accurate from an expansion enclosure. There are lots of variables including the distance between the panel and expansion enclosure, but personally I would only use extended temp sensors connected to the panel directly.

 

[kurtmccaslin]

Thanks.   I will wire it directly into the panel.   It will require pulling some extra wires from the garage, but that will not be a problem as I have an empty 2 inch conduit.
 
I am currently having trouble with accuracy on my bench setup.    I have a 31A00-8 connected directly into the panel.   It is reading about 15% low on humidity (but right on with temperature).   Any thoughts on what might be causing this or the solution?

 

[ano]

That is a pretty common complaint. The humidity sensor is still a voltage generating sensor, so the good news is it can connect to an expansion enclosure. The bad news is I don't think it can be adjusted. If you are using a bunch of these and they are not consistent from one to the next, you might want to contact Leviton to see if they have a solution. This is a problem that many have brought up.