accuracy poll

That is actually what for me this is about every instrument has a manufactured tolerance. A range that the accuracy is supposed to be with in. The issue is most people don't pay any attention to that. For example the specs on my Accurite state that it will be with in 2ºF +/- of correct. So unless I have a better thermometer I have to accept its deviation. It could be correct spot on or it could be 2 degrees off. 88-92 if it is reading 90. No way of knowing unless you buy one that has finer tolerances. You can get digital ones that are 1º or 0.5º or 0.01º The price goes up monstrously as you get less possibility of error. A traceable one means before it left the factory it was placed on a calibration bench and tested that it was correct and it is certified by the manufacturer with a serial number and the records of that test.

Does this help some?

To be honest I just don't worry about it. As long as my snakes are healthy and thriving it's accurate enough for me. :gj:

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Originally Posted by kitedemon

I spoke to a electrical engineer yesterday about that very thing, his response was basically the accuracy comes from the probe and the precision the controller.

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Unless you're like me and cheat by using a sensor in the probe that is a controller. :^) The sensors in the Herpstat probe are digital. They feed back a data stream with the temperature info and my thermostat designs just read that data.

The most common thermometer sensors (thermistors) are resistor based and as the temperature change their resistance changes. Simple huh? Except you are connecting that resistor to a cable so now you add the resistance of the cable. Then you couple that to several other components inside a controller which also usually have 2-5% tolerances and often all of that is affected by the quality of the power regulation the unit is running. So to an extent every circuit could have a different reading. For me there were just too many variables that could affect the true temperature with this setup so I went digital.

Before we ship any of our probes they are plugged into a Herpstat Pro unit four at a time and they all have to be within a degree to pass the test. Usually they are less than half a degree difference. The stated accuracy from the manufacturer of the sensor is +- .9 degrees but in our testing they are even closer.

One thing I want to point out is alot people cause themselves problems by using aluminum tape to secure a probe. Aluminum is a good conducter of temperature but it can pull heat away from the probe as well acting as a heatsink. Any other non-metallic tape is better. :)

Dion Brewington
Owner, Spyder Robotics

I stopped using humidity gauges over 6 months ago because they were so inaccurate.

Dion,
I actually trust the herpstat probes over everything. I have always found them to be very accurate. I use it against the others the empty probe slots I have I use for checking temps.

Spitzu should I tell you I went through 14 different guages before I settled on the ones I use now? I hear what you are saying there. The silly things are the worst ever, the current ones I have so far have not wandered much but at least I can change them when they are wrong rather than tossing them out.