Interference between extruder motors and PT100

Idir

The factory sensor comes connected on a 3 wire configuration and sadly I can't access them because they are heavily encapsulated all the way though, but I can try grounding the extruder-hotend setup as suggested by @o_lampe. If that doesn't work I guess I'll try switching them for PT1000 since they seem more resilient. I'll update with the working solution if I get there for future reference.

Thank for the quick response!

Phaedrux

3 wire should be pretty resilient to interference. 4-wire is best, but 3 should be ok. Hopefully the grounding helps.

o_lampe

@Idir
there's still a chance, you have a broken sensor or bad solder joint. The connections between mainboard and daughterboard can also cause issues. Maybe the extruder draws too much current, it causes a brownout or huge voltagedrop on the daughterboards?

dc42

Unfortunately, stepper motor cables generate interference in other wires that they run close to.

Please post a photo of the PT100 daughter board so that we can see what revision it is. The newer boards have additional capacitors to help reject interference. It's possible to add capacitors to the older boards.

Idir

@dc42

Here's the picture of the boards. Sorry for the quality, but it's what I managed to get from mi client.

I have not been able to try yet grounding the head yet.

dc42

As the PT100 wires run close to any stepper motor wires for a substantial distance, then using shielded cable for the PT100 wires should solve it.

Idir

The PT100 wires and the extruders wires go through different cables (although I suspect they are not insulated) and are relatively separated, but the cables go through the same ducts for about 4-5 meters, so I guess that might be a problem. I don't have detailed photos of the cable arrangement, but here's an overall look of the machine in case is helpful.

Idir

@Idir said in Interference between extruder motors and PT100:

The PT100 wires and the extruders wires go through different cables (although I suspect they are not insulated)

Sorry, I intended to say that they are probably not shielded. They are of course insulated and I've checked for any derivation.

hackinistrator

2000 deg sounds more like a connection issue then interference .

Idir

After fiddling everything for several hours I didn't manage to find a bad connection or to solve the problem. I ended up changing the sensors for thermocouple cartridges and after connecting them directly to the board they just work, so I guess that's the end the problem for now.

Thanks to everyone for the quick response and the help.

waruta

@idir I've got an old BigRep 1.2 as well and wondering if I could ask you for some info as the local distributors/resellers are proving most unhelpful.