OK, so, finally worked out the issue with the Re-Arm Temperature issue I have been experiencing. Working with @Tom_Keidar who had the same issue, it seems that there is a lot of noise going into the Re-Arm causing issues with temperature reads. He’s added a low pass filter with a decay of 4 into smoothie for me and it’s cleared the issue up. So basically it’s either the RAMPS (more likely) or the Re-Arm itself. Tom’s going to speak to Arthur about it, as it may be a little too specific to be added in.
Marlin github repository has issues/information on this as well, afaik it’s a HW problem.
@Oystein_Krog Oh it is, but it needs a choke to fix it, so basically adding a software low pass filter cleans up the noise coming through’
@Ax_Smith-Laffin Very interesting, thanks for reporting this. I’ve been using a Re-Arm for quite some time. I’ve spent hours pid tuning my hot end temperature but to no avail. Could you share the modified code?
You can try Marlin 2.0 with the Re-Arm. It had that issue fixed.
@Bajdi_Electronics - I’m still running tests currently. As soon as I’m happy with it, I’ll get the code shared.
@Panayiotis_Savva - I really don’t have time to sit and re-configure at the moment. I have orders coming out my ears and need all 5 of my printers running all the time. To give you an idea of the volume I’m going through on just one printer I’ve killed around 4KGs of Black PETG in 2.5 weeks. Thanks for the heads up, but not viable for me at the moment.
Did you get the SD lockup’s solves as well?
@Griffin_Paquette - uh… aye on the Delta, that’s chugging away nicely
Actually the problem is a H/W issue… any ADC on the LPC1769 needs to be powered by AVCC and AGND, these are special filtered powerlines, AFAIK the ramps uses Vcc and GND which injects noise into the entire ADC circuit. At one point Roy was going to put the thermistor ports on the re arm board instead, so it could use the avcc and agnd. If you are plugged into the ramps thermistor ports there will be a lot of noise.
Smoothie already has ample filtering in the ADC code, as well as oversampling, so adding more to the code is not needed. the H/W needs to be fixed instead.
The noise issue with ADC is well documented in the LPC1768/9 documents.
@Wolfmanjm - I had mentioned above that I know it’s hardware, I just don’t have a choke to hand to filter the noise, this was the next best option for the moment. Ultimately, I’m probably going to swap it out.