PT100 Wiring
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I used an online calculator and PT100 Resistance table to come up with these values
M305 P1 T110.23 B-356.98 C0 R4700 L0 H0 X200
anyone see any issue with the negative value?
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Actually you don't need any of those parameters. I have none and it just works: M305 P1 X200
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As Alex says there is no need for the T B C R L H switches on M305 for a PT100 - they are for thermistors, the MAX chip we use for the PT100 does all that internally.
Regarding the solder jumpers, David and I discussed this and came to the conclusion that adding wire jumpers (as you did), was easier that cutting solder jumpers if you have a 4 wire PT100, using a 2 pin jumper would have made the board footprint bigger.
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Thanks for the Tip regarding the M305 P1 X200
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This is a great thread, hope folks don't mind me adding a few bits of info I learned hooking up my pt100 for future reference if anyone searches on it.
Consider using shielded cable if your PT100 wiring runs in a bundle with the hot end heater, stepper, servo, etc.. wires attached to hot end carriage.
Ground the shielding wire. The PT100 daughter board appears to be very sensitive to inducted currents / EMI. It constantly read 2000 when the hot end heater kicked in. Once I ground the shield wires in the bundle, the sensor worked liked a charm.Use good low resistance wire, per the note in the duet3d.com page, https://duet3d.com/wiki/Connecting_PT100_temperature_sensors
Limit number of connectors and/or ensure connectors are properly crimped.
I had two conenctors and 26 or 28 gauge wire in one section of my wire path to the PT100. The crimp of one connector on the small wire was not perfect and introduce additional resistance and raised the temp reading by 30-40 degrees C. Removed that connector and small wire and instead used 20 gauge wire directly into PT100 daughterboard. Temp is now with +/- 1 C of room temp. -
Wow nice post. I was looking for info about exactly this. Wow perfect photos of the wire from 2-1 and 3-4. I wasn't getting the 'add wire' explanation. Could be nice to have that photo on the wiki. Nice job guys!
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I'm trying to make the setup a bit easier and I was wondering if using this for a 2 cable PT100 sounds like a good or bad idea:
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Just finished a video showing how to make a simple adapter that fits perfectly on the PT100 RTD Duet3D board.
https://www.youtube.com/watch?v=GJCLiqsz_ho
Hope you guys like it! Works like a charm!
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Best cringe worthy video with an Exacto blade I have seen in a long while. I was anticipating a sliced finger every time he uses it in an unsafe manner. If you're going through all that trouble, just solder the damn jumpers and use the correct 2 pin molex KK connector.
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Nice job!
