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Messages - jry

3
Project logs / Re: Really universal soldering controller
[quote author="sparkybg"]There is not a problem. C210 has so small thermal mass and so small resistance that even one mains period of 24V AC is able to heat it a few degrees up. Peak electrical power of these tips is almost 300W at 24V.[/quote]

I didn't study your code, but wouldn't it be possible to shutdown MOSFET in the calculated time and don't wait for whole mains period? I plan to examine this option in my JBC controller. Maybe with some simple MOSFET power dissipation model, so we can fall back to whole period switching to lower MOSFET temperature.
5
Project logs / Re: Simple DIY JBC soldering station
Next logical step is replace TRIAC with two back to back MOSFETs. Power dissipation when running with 50% duty cycle is 40mW per one MOSFET. So with 100% duty cycle and two MOSFETs it is 160mW total. Compare it with 6W on TRIAC version and it is clear MOSFETs are better solution - no heatsing required, could sit directly on PCB.

tbc...
6
Project logs / Re: Simple DIY JBC soldering station
But why not try the TRIAC version anyway, just for fun. Probably simplest JBC T245 and T210 driver possible. Works fine with small TRIAC heatsink for ordinary soldering. For high thermal tips such as C245966 you would need much bigger heatsink (for dimensions see ST AN533 or Semiconductors AN10384).
7
Project logs / Re: Simple DIY JBC soldering station
Another not-so-good idea was TRIAC used as heater switch. With C245 tip running on full power (Vrms=21V with my transformer) we are talking about dissipated power 6.5W, 1.3V (rms) voltage drop on TRIAC.
8
Project logs / Re: Simple DIY JBC soldering station
Yes, I have some information.

Breadboard from my pictures is disassembled and stored in my drawer. It wasn't very good prototyping platform due to parasitic capacitance and layout I used. I don't say it couldn't be done, but I hit several problems. I also don't use ATmega for my projects anymore, switched to STM32 MCU family.
10
Project logs / Re: Simple DIY JBC soldering station
Sparky, thank you for feedback, I really appreciate it.

Regarding opamp: I'm testing AD623 connected as you described and it behaves strange. There is a lot of noise on AD623 output:

[attachment=1]

I'm also getting only 1.2V output max, regardless of VS+ (testing on 3V - 5V) and gain resistor value. I did test standalone AD623, just power supply, gain resistor and voltage divider with potentiometer instead of thermocouple. Output seems to be VERY nonlinear, no chance to get output over 1.2V with JBC thermocouple voltage on input. I don't get it, maybe I should look at another opamp when I see arhi's TC reading noise level.

I have power supply inputs decoupled on both MCU and AD623 according to specs.

Here is noise level on AD623 output:
[attachment=0]
I'm reading AD623 output in the same phase (zero crossing), but it still seems noisy to me. 60mV of noise on 0 to 1200mV scale I can get from AD623 output.
14
Project logs / Re: HAKKO (907ESD) and SOLOMON (SL-10/30) soldering iron dri
[quote author="thenewguy"]Anybody have any luck with the JBC hand pieces?[/quote]

Please read complete threads (there are JBC related posts inside):
viewtopic.php?f=56&t=2457
viewtopic.php?f=56&t=5264
viewtopic.php?f=56&t=6302
http://www.eevblog.com/forum/testgear/j ... /msg376294
http://www.eevblog.com/forum/blog/eevbl ... -teardown/
http://www.eevblog.com/forum/reviews/jb ... sassembly/
http://www.google.com/patents/EP1086772A2?cl=en
15
Project logs / Simple DIY JBC soldering station
My learning project based on several great information sources:
HAKKO (907ESD) and SOLOMON (SL-10/30) soldering iron driver
My HAKKO classic and T12/T15 soldering controller
eSol - DIY digital soldering station for 80 Watts Weller iron WP80
Thanks guys!

Current status: transformer inside old PSU housing as temporary solution. I don't want to mess with mains on my desk.
[attachment=1]
For now battery powered (3.2V LiFePO4) logic part. Opamp, Atmega328p, three buttons, LCD (waiting for b&w OLED instead of this one for better contrast and faster refresh rate).
[attachment=0]
Next stage: logic level triac driver (or two MOSFETS), first tests, PID controller.

(UPDATE) Other sources:
JBC soldering iron stand wiring
EEVblog #472 - JBC CD-2BB Soldering Iron Teardown
JBC T245 Handle disassembly
JBC Industrias S.A. - EP1086772 A2 - Electric soldering iron patent

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