Lightobject.com Support Forum

Using JLD612 and PT100 probe.

For the first minutes of operation after being plugged in, the actual temp is unstable by +/5 degrees F. After a period of time the temp converges as if it is filtered.

I do not think it is a noise issue as described by previous posts.

Is this normal?

Dave-
Do you have the unit set for Pt10.0? This will show temp in .1 degree increments. It the fluctuation full degrees +-5 or tenths of degree? That much fluctuation in tenths is not so much.

It also depends on what is being sensed -- in my hot tub, from a warm restart, the measured temp will vary a lot while the temp of the water forced over the sensor is stabilizing, so some initial wobble is not unusual in my application.I do use the Pt10.0 setting...

The fluctuation is +/-5F not +/-0.5F
Also I notice if I wiggle the shielded cable the fluctuation is +/-5F.
Is this normal?
Thanks for the tip on Pt10.0
I wondered what that was.

mythopoeic.org/sous-vide-cooking had a similar problem with the temperature readings jumping around.
Coupling the PT100 shield to one of the return wires seemed to fix it.

Did you solder directly to the shield?

Excellent sous vide implementation.

Did you think about making a homemade stir plate to stir the water instead of water bubbles?

It's not my setup, but I've gotten a few good tips from it

For now, I'm just using an alligator clip to connect to the shield.

I followed Mike's tip and connected the blue leads of the Pt100 temp sensor to the shield using an alligator clip and the stability improved dramatically. I also tried connecting the shield to AC ground and there was poor stability. I wonder if there is any advantage in connecting AC ground to the shield and to the blue leads.

Dave, I wouldn't connect AC ground to anything associated with the controller. I think it needs to float. Maybe Marco will have something to say about this.