My new indoor Airlab device reads a high temperature, almost 10 degrees F. I went into the T3000 software to apply an offset, but I can’t find where to put in the offset value. I do see the offset value in the Modbus register map.
- Is there a place in the T3000 software to apply an offset?
- If no, can you provide the details of how the offset works? It says unsigned 16 bit, does it have a sign bit or 2’s compliment? Is it in F or C? (I am using F for my units)
You can set the temperature offset in the T3000 software, it does not matter degrees Celsius or Fahrenheit.
- Click the “inputs” button
2.Set “Calibration” and “Sign” of TEMPERATURE, because your temperature is 10 degrees higher, then the sign is set to negative, the calibration value is set to 10.0, and the accuracy is 1 decimal place.
Thank you for the quick reply with the directions!
I have the airlab in a controlled air environment to analyze its accuracy to temperature and humidity. I found that the airlab electronics itself, or possibly the LCD is causing the hike in temperature by this amount approximately 6-10 degrees F higher. My room is 77 degrees F, in fact the air vent is blowing 72 degrees F. The airlab is reading 84.x. It’s temperature is running at 86 degrees F. So Airlab itself is creating the false offset in its temperature sensor. If you try calibrating, its going to only be an approximate to the initial temperature you’re setting against.
There’s a certain amount of internal heat gain from the electronics. Please repeat your test with the unit mounted on the wall at around light switch height. Make sure to locate it out of the way of drafts and direct sunlight as best you can.
Hi Maurice, I’ve mounted it on a few other locations, the wall, and the edge of the metal desk with full airflow around it. It still is much warmer than the ambient. Today’s high was 78 deg F. After hours of not being in the room, everything is acclimated at 78. The airlab is simply hanging by its wires on a metal desk edge with all of its air vents freely venting. Still reads well over 5 degrees higher. This is a very bad thing if you’re trying to regulate air handlers and conditioning if it keeps power-hungry units running to cool the place. I am sure I can offset it, but what happens when temperatures drop to let’s say below 65 ambiance? Would the offset be incorrect as now you have a heat generator source when the rest of the room is cold?
In addition, am I supposed to see any sound level change at all? It never changes from a value of 61, regardless of the sound level tests. The occupancy sensor does change slightly from below 140 to just about 167, but it never changes status from unoccupied to occupied. Should it? I’m wondering if this is a flawed unit.
We put a lot of effort into keeping the internal heat gains to a minimum, in our tests we had it down to around 2F as I recall and that is basically a fixed offset which can be calibrated out easily. I will have our team repeat the ‘internal heat gain’ tests and we can compare notes. 5F sounds way too high.
That said, you could try extending the thermistor outside of the case. We could ship with one of these ‘flush mount’ type sensors which you would mount nearby. Its not ideal I admit but would get you going till we have more time to dig into this with you.