@dc42 @droftarts Thank you again very much! Our device had a current draw of 100 mA only, and based on your advices we were now able to start using OUT 4-6 for our 24V devices. What a great feeling, thank you for excellent support!

@T3P3Tony Hi, and my apologies for the late reply. I repeated my measurements and got a bit more accurate values for the U and V based on those. I now added them in place and neither of the sensors was anymore showing any error, so I think that I might have mixed up with the U and V values. I ensured that the readings now also improved a lot, when using those correct U and V values. So thank you for these parameters for the developers :)!

@T3P3Tony Hi Tony, and thank you for your help. I got it now working well. I think I had an issue previously when I had configured my first sensor to have

M308 S1 P"spi.cs1" Y"rtd-max31865"

instead of having it

M308 S1 P"spi.cs0" Y"rtd-max31865"

based on the naming on the daughter board. But now I got all my three sensors working with two daighter boards.

BR; Heidi

Hi,

I have read your provided instructions (Temperature connecting PT100) on how to connect Pt100 sensors using temperature board on Duet mainboard 6HC.

Is the possible number to stack daughter boards limited to two? Howabout, is the number of Pt100 sensors that can be connected to the daughter board only one or two? Also, should the temperature board work without having the 100Ohm resistor added to the second connector when measuring the temperature with another connector in use (not for test purposes)?

I am asking this because I would need to connect three Pt100 to my system, and got an impression that the resistor would not be needed and I could use both connectors of the daughter board for measuring temperature ?

BR, Heidi

@droftarts Hi, I am sorry, but I edited my above post after you had marked it solved, based on my comment. However, I noticed another questions related to heater fault detection. Could you answer those still? Thanks in advance. BR, Heidi

@droftarts @gloomyandy @Phaedrux Hi, now we have made your instructed corrections and the above problem with heaters were solved. Thank you for these excellent guidance and support.

I still got one question in mind, related to my earlier problem with my heaters, when I had them wired in an old way and when wiring like now. I had a few cases with the old wiring, when I either did not have the Pt100 temperature sensor connected to the board or my firmware crashed because of my written lines on the configuration file related to the global variables at that time. With the first case I got a heater fault warning and a comment on n/a as the temperature on the web interface, while with the latter case the firmware was not responsive. In both cases, both of my heaters turned on (even without setting-up any input for them), which is not desired.

Was these above events because I had my heaters wired and configured in a wrong manner, and does the above change avoid this risk? I had also my heater fault detection set with M143 as described below but it wasn't able to avoid this unwanted heating:

M143 H1 P0 S300 A0
M143 H2 P0 S180 A0

Also, should I have my allowed lowest temperatures be configured with M143, and not only the maxima? Unfortunately I don't figure it out what does the monitor number mean (P in above commands)? Is it somewhat related to the H term?

I also tried to read about these issues from: https://docs.duet3d.com/en/User_manual/Troubleshooting/Heater_faults, but based on that I assume the firmware should automatically detect at least bad wiring issues?

My firmware is: 3.5.1.

BR, Heidi

@T3P3Tony Hi, and my apologies for the late reply. I repeated my measurements and got a bit more accurate values for the U and V based on those. I now added them in place and neither of the sensors was anymore showing any error, so I think that I might have mixed up with the U and V values. I ensured that the readings now also improved a lot, when using those correct U and V values. So thank you for these parameters for the developers :)!

@gloomyandy Hi, great! Thank you for your excellent reply, I think we will correct our wiring accordingly, but first I will wait my colleague to come back from holiday. When we have tested this, I will let you know if we managed to get rid of the problem.

With best wishes, Heidi

@gloomyandy thank you for your help, I appreciate it. I tried to draw a connection diagram of another of the heaters, and both are connected similarly. Hopefully it is ok, and please, ask further questions if that is unclear and I try to specify it better.

I am not so familiar with electric connection drawings after my school, and my colleague who did the connections is now on vacation.

@gloomyandy Thank you for your reply and notification. Yes, we have configured inverted our cartridge and pressurized air heaters, powered with DC-AC solid state relays (IN: 3-32VDC or 5-24VDC OUT: 24-280VAC), because if they were non-inverted then they would turn ON at start-up when powering ON the Duet 3 6HC board. We have connected the positive wires of the heaters to the out1 and out3, and the negative wires to the GND of board.

When I measured also with a multimeter and saw a short-term -0.040VDC voltage at the start-up of the board, which then dropped.

BR, Heidi

@T3P3Tony and @dc42 Thank you for your clear presentation on how to modify those values. I did my corrections accordingly. However, I noticed that with another of my heaters the U and V values were ok to be added on the configuration file. However, with the another the values were such, that I received an erraneous temperature reading of N/A on the web interface and 2000Cdeg on the user interface panel.

The temperature values for the two Pt100 sensors have the following correction coefficients U and V:

Sensor 1 -> showing reliable results
U-0.00332
V0.066408

Sensor 2 -> showing the error
U-0.01662
V0.332326

What could cause the problem with the another sensor?

BR, Heidi

@Phaedrux Hi, thanks for your help.

I upgraded my firmware and web interface to 3.5.1. and it didn't help with this problem. Also, at start-up each led of those high current outputs (OUT 1 to OUT 3) are turned on. OUT 2 is connected with a servo, and OUT 1 and OUT 3 with by above mentioned heaters 1 and 2. Actually, I noticed from my Panel Due that it gives a warning that my heater 2 is expected to experience overheating problem.

I was thinking, if this problem could require some electrical isolation for example with relays?

I would have also another question related to configuring heaters: As my sensor could detach from the board and initiate error or wrong temperature reading for the heater and trigger unwanted excess heating, I would like to prevent this by determining the minimum temperature that I allow for the heater. Can I program it using M143 command? Like here:

M143 H1 P1 S0 A0 C1 ; Minimum allowed temperature for heater is is 0C degrees, which initiates heater fault and heater truning off

BR; Heidi