That's basically the ideal setup in my opinion, although I have the usb on the front. I temporarily added the rotary encoder in place of the center button. I still need to finalize the rotary version, after which I can revert this one back to button operation (I love the rotary but this front is too nice for a half baked rotary hack).
I wish there was a cheap option to make this locally, but unfortunately this kind of work is expensive over here.. But I like the quality.
Your frontpanel looks Indescribably good can you please upload your schaeffer ag Frontplatten Designer source files (front & back). I would like to copy your case
I suppose this is C245 on the movie? If yeas, the resistance is definitely NOT OK - C245 has 2.8 - 3 ohm resistance, and the graph shows 5 ohm resistance.
VIN @ fuse is OK. VINT is also ok. Check Vacdc @ R51. It must be equal to VIN / 28, with the same shape.
Check SHUNT voltage between front board flat cable connector pins 5 and 7 - it must be the same as on shunt resistor. Then check VSHUNT voltage on C59 - it must be 23.5 times that on shunt resistor, with the same shape but with less noise.
Show me VSHUNT voltage with faster H sweep (500us). It must always be constant, with similar shape as Vacdc, while heater is heating up. Use VSHUNT as trigger source and measure Vacdc on another channel to be able to view them both.
Check your connectors and solder joints between back PCB and instrument's connector. I had some issues there in the past, no matter how ridiculous this sounds. Some connectors behave REALLY nasty sometimes. This is why I replaced the chinese connectors with Amphenol ones. It is fair to check chimps on the cables between back PCB and instrument connector also.
You may try to replace flat cable between front and back boards. I had issues there also. What I do is heat up the cable a bit (maybe around 80 degrees Celsius), before pressing it into the connector. The flat cable PVC insulation is much more soft and it is easier for the blades of the connector to penetrate well and have good contact with the wire cores.
At first many thanks for your help and sharing this awesome project
After few hours testing I found the problem. It was the resistor R45 I changed the resistor from 3kOhm to 1kOhm. The "heater shortcircuit" is gone and the heater resistance curve is Smooth.
F=full power, H=1/2 power, Q=1/4 power, E=1/8 power
Check the current sense (SHUNT) circuit.
Both your tip must show "ACF" when on 24V. All your problems come from malfunctioning VIN or current sense circuits. The controller thinks that heater resistance is much smaller than it is. (or much higher as the graph shows).
I checked the current sense circuit 3x times. I couldn't find any abnormalities. VSHUNT_@R45_AC_supply --> looks ok for me
Then I looked at VINT circuit. With 24V AC transformer i measured ~2.21V @ ZD4, ~0,82V @ R51 --> The two measured voltages are plausible to me.
With my Oscilloscope i measured the voltage @R46 --> It looks strange to me. What do you think about this?
Hmm... something is VERY wrong with current sense circuit I guess. The gray line (heater's resistance) must be flat, but it is not. So either the input voltage or the input current is not sensed right.
Check the flat cable between front and back (VIN and SHUNT signals). Also check the -0.6V power supply, although it must be OK, because otherwise the temperature reading will be corrupted also.
T12 heats up extremely slow - this is also because current or voltage sense circuit is malfunctioning.
So chek your flat cable. Check it's connectors solders and replace the cable/connectors.
Thank you for the hints The T12 heats only slowly when the "heater shortcircuit" is / was active. I measured the current on the ac inlet (~1.4A when the error is active, ~2,5A when the T12 works normal). I'll check the flat cable / connectors and the current and VIN circuit.
What I also noticed is that the error only occurred in ACF operation, with ACQ I haven't had the error yet. What does q abbreviate? ACF = alternate current frequency?
I used for the last years the DC for powering the unisolder. This is the reason why both plugs (and ac wire) are connected. When I try AC I disconnect the DC SUPPLY.
I soldered a 10k resistor and flashed your newest fw 2020.06. With the new fw the "heater shortcircuit" error is not that common as with the fw (2020.02) which I user before.
EARTH connection is iron-specific. It is connected to the outer shell of the iron. On some irons SENSEB is also connected there (T245), on some irons it is connected to VOut-.
EARTH must not be connected anywhere else, just to enclosure (if it is made of conducting material), and tip's outer shell.
Make pictures of your setup and I will be able to comment more.
This are my pcb's. I'll solder 1k resistor between CS and GND and update to your latest version.
I attached an picture of the calibration menu (with toroidal transformer), the resistor has 10.1 Ohm. When I used it with DC supply I don't connected the mains earth. At first I tested AC without main earth connection, turning testing I connected the earth to SENSEB (at c245 connector) and connected with 1M resistor in series to mains earth.
I built my unisolder in 2017 and used it with a DC power supply. The unisolder ran without any problems and I was very happy with it.
I am currently planning a housing and now also want to use a toroidal transformer. I have already bought a 24V 120VA toroidal transformer. With the transformer connected, I get the following error message "heater shortcircuit" after heating up. After about 3-5 seconds the error message disappears and the soldering iron starts heating up again.
I have this issue with all my solder irons which I use (C245, T12).
I never had this problem with a DC supply.
When I reconnected the DC supply the error doesn't occur.
I checked the calibration (there was no offset).
Do you have a tip for me? I got no further with finding the error
can you please upload your schaeffer ag Frontplatten Designer source files (front & back). I would like to copy your case 
