xsherlock 0 Posted December 22, 2020 Share Posted December 22, 2020 Hi ALL, I need to run a longer cable from the PTC bricklet to the the PT100 probe (the one from your shop). I used 2 x1mm^2 sensor cable to extend the 1m that comes with the probe. 7m long. Do you think that can affect the results much? I have some concerns , as that is an important readout I have 2 sensors in exactly the same location, glued together with a thermal glue into one blob attached to the pipe. They are about 1-1.1 degree apart, and output looks a bit noisy. (I read them every 2 seconds) What do you think? Quote Link to post Share on other sites
batti 0 Posted December 23, 2020 Share Posted December 23, 2020 Hi, as far as I understand your description you use a 2-wire probe, right? For a 2-wire probe there is no wire resistance compensation. One possibility would be to connect the 2-wire probe with 4-wires, such that you can compensate for the wire resistance. Regarding noise a longer cable might induce more noise. In this case a 4-wire connection should also improve the situation. Quote Link to post Share on other sites
xsherlock 0 Posted December 29, 2020 Author Share Posted December 29, 2020 Yes I you your probe from the shop that is 2 wire. How do I connect a 2 wire PT100 with 4 wires? TIA Quote Link to post Share on other sites
batti 0 Posted December 30, 2020 Share Posted December 30, 2020 A PT100 probe is a 2-connector probe. When you use a 4-wire connection you connect two wires to each connector as close as possible to the probe. Quote Link to post Share on other sites
xsherlock 0 Posted Wednesday at 08:19 PM Author Share Posted Wednesday at 08:19 PM (edited) Ok so I rewired the setup and now 2 sensors (Output 1, Output2) are 4 wire (7m extension). 3 named Noel are old setup (2 wire 7m extension). And for comparison I added Poiol skimmer to the graph that is same PTC probe on 2 wire directly to PTC bricklet on the same RPI HAT. As you can see the extension is the problem , adding 2 wires did not improve the noise. Probe directly into the bricklet is super clean. What else could be a problem here? TIA Edited Wednesday at 08:19 PM by xsherlock Quote Link to post Share on other sites
batti 0 Posted Friday at 03:29 PM Share Posted Friday at 03:29 PM Hi Sherlock, is it possible that you send me a picture of your extension? The connection at the sensor and at the Bricklet is what I like to see. I'm pretty sure that you have done that right, but sometimes it is much easier to see it on a picture that to explain it by words. You have configured the PTC Bricklet for 4-wires, right? Quote Link to post Share on other sites
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