Phidgets Plugin Discussion

Posted on
Fri Jul 24, 2020 10:48 am
mpleeds offline
Posts: 33
Joined: Jul 02, 2012

Re: Phidgets Plugin Discussion

Thanks for the response Berkinet.

I had the Trigger Threshold set to 3 during my initial sauna test (running side by side with existing 433 RFX BBQ probe) and noticed that it only reported changes of EXACTLY 1.2° F (not granular enough for sauna temp control). When lowering the Trigger Threshold to 2, readings became very erratic ("thrashing"). Could this be the limitations of the 1124 or a possible bug in the plugin? Based on your comment that the 1124 is not "super stable", I am thinking of upgrading to a thermocouple and Phidgets 1048 sensor with the hope that readings will be more reliable, down to around .5° F.

Thoughts?

Posted on
Fri Jul 24, 2020 11:05 am
berkinet offline
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Joined: Nov 18, 2008
Location: Berkeley, CA, USA & Mougins, France

Re: Phidgets Plugin Discussion

mpleeds wrote:
...I had the Trigger Threshold set to 3 during my initial sauna test (running side by side with existing 433 RFX BBQ probe) and noticed that it only reported changes of EXACTLY 1.2° F (not granular enough for sauna temp control). When lowering the Trigger Threshold to 2, readings became very erratic ("thrashing"). Could this be the limitations of the 1124 or a possible bug in the plugin? Based on your comment that the 1124 is not "super stable", I am thinking of upgrading to a thermocouple and Phidgets 1048 sensor with the hope that readings will be more reliable, down to around .5° F.

Thoughts?

A trigger of 3 should be fine. And, at this point (several years) I am certain there is not a bug in this part of the code. BTW, by stability, I mean there is some jitter in the 0-5v output from the 1124, thus the thrashing you saw. One test is to look at the phidget in the Phidget control panel and see what it reports in raw value and then convert that to ºC using the formula Temperature (°C) = (SensorValue x 0.2222) - 61.111 There could be other factors, such as is the 1124 in open air or attached to something. If it is attached, the heat will change at the rate of whatever it is attached to.

Finally, the 1048 is excellent, but for your application, you shouldn't need it. If you can confirm the 1.2º difference using the control panel, I would suggest calling phidgets support, you may have a faulty 1124. I mention re-creating the problem with their own code to remove the plugin from the issue.

Posted on
Fri Jul 24, 2020 12:01 pm
mpleeds offline
Posts: 33
Joined: Jul 02, 2012

Re: Phidgets Plugin Discussion

Good idea. I tested in Phidgets Control Panel and came up with a variance of around .1° C when set to lowest change trigger and interval ≈ 66 ms(see screenshot). Would this indicate that the 1124 is ok and that something is getting lost in the plugin translation?
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Posted on
Fri Jul 24, 2020 12:23 pm
berkinet offline
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Posts: 3408
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Re: Phidgets Plugin Discussion

mpleeds wrote:
Good idea. I tested in Phidgets Control Panel and came up with a variance of around .1° C when set to lowest change trigger and interval ≈ 66 ms(see screenshot). Would this indicate that the 1124 is ok and that something is getting lost in the plugin translation?

If you were connecting through the web service then for the interval will mean nothing . If you are connecting directly via USB then you probably should set it at 16 ms to match what is happening in the plug-in. But, beyond that the 1/10 of a degree difference is exactly what would be expected and what you would see with the threshold set to zero. Set a threshold higher for example two or three, and then see when it changes. That will give you your comparison.

Posted on
Fri Jul 24, 2020 12:59 pm
mpleeds offline
Posts: 33
Joined: Jul 02, 2012

Re: Phidgets Plugin Discussion

I will continue to experiment. Thanks for the assistance and for creating this great plugin!

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