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Project logs / Re: HAKKO (907ESD) and SOLOMON (SL-10/30) soldering iron dri
And the shipping is a bit expensive, only worth for large orders.
The ebay is an alternative.
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Messages - diogoc
And the shipping is a bit expensive, only worth for large orders.
The ebay is an alternative.
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Project logs / Re: HAKKO (907ESD) and SOLOMON (SL-10/30) soldering iron dri
You're giving us a new light about information yet unknown of that soldering stations.
If we know what kind of material is inside the tips we can determine with greater precision any temperature.
Thanks for your work.
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Project logs / Re: My HAKKO classic and T12/T15 soldering controller
Using DC does not necessarily mean more power to the heating element because we have to turn off the power to make the readings of tip temperature. Sparkybg use the crossing for zero of the mains wave to do the readings.
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Project logs / Re: My HAKKO classic and T12/T15 soldering controller
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Project logs / Re: My HAKKO classic and T12/T15 soldering controller
[quote author="sparkybg"]That's why you are reading different temperatures whan the heater is on and off - you are not giving it enough time, so the power to the heater devastates yous ADC results.[/quote]
I turn off the heater, wait 1.8ms, make the ADC measurement 4 times (pre-average), turn on the heater, and then I make the 16 last values average and run PID. I confirmed with the oscilloscope that after 1.8ms the voltage in the amplifier output has stabilized.
[quote author="sparkybg"]Also, instead of averaging you can use another type of digital filtering that behaves much like an RC filter. For example, if you have a variable for averaging, called ADCAvg, and you read the ADC into variable called ADCVal, than for every new ADC value you can do ADCAvg=ADCAvg-(ADCAvg>>3)+ADCVal. This will result in averaged ADC value in the ADCAvg, multiplied by 8 in our case. It behaves differently than averaging, and it uses only one variable for averaging instead of a buffer with last 8-16 results.[/quote]
Your formula for the digital filter may have other advantages over the simple average but for the mathematical simulation that I did (a variation of temperature from 0 to 300) your formula takes much longer than 16 cycles for the value of the temperature reaches 300 ºC.
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Project logs / Re: My HAKKO classic and T12/T15 soldering controller
I reduced a lot the capacitors that I had in the amplifier and so I have a relatively fast response signal to the ADC.
My PWM period is 200ms and I turn off the heating 2ms to acquire temperature so the maximum PWM is 99% which to me does not matter.
To compensate for the reduction of the capacitors and achieve a stable temperature value, I make the average of the last 16 values of temperature. I can increase the number of averaged values but I am afraid this may make the PID slower.
One thing I noticed is that as the tip temperature is different from the temperature where sensor is so I can not calibrate the temperature value for all temperatures. I calibrated to 350 ºC and the other temperatures do not match exactly, but nothing too serious.
At the moment I lack mostly the adjustment of PID parameters. I made a program in C# that receives all parameters of the controller by RS232 and displays them graphically allowing me to more easily make the adjustment of these parameters.
You can give me any tips on the best strategy to adjust the PID?
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Project logs / Re: HAKKO (907ESD) and SOLOMON (SL-10/30) soldering iron dri
For me JBC is JBC and is not comparable, but it is expensive and there is no Chinese clones
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Project logs / Re: My HAKKO classic and T12/T15 soldering controller
Every thermocoule in the world will give you 0(zero!) voltage at ambient temperature. It will start building voltage on it after you heat it above the ambient temperature or cool it down below ambient temperature. Thermocouple measures the temperature difference, not the temperature itself.[/quote]
OMG it is true. I do not know what I was thinking...
I'm trying to do my own soldering controller before give up and build your controller :)
my idea would be:
- use a laptop ac adapter for the power supply to reduce the the weight and dimension
- use a AD8495 for the thermocouple amplifier. It is for K thermocouples but if I linearize it in software it could work (maybe a stupid ideia)
- use a pic18f2550
- use a 3310 lcd
- use a rotary encoder to change the temperature
this probably is not the best topic to expose my questions but you are the only one here who has worked with T12 tips
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Project logs / Re: My HAKKO classic and T12/T15 soldering controller
I'm trying to read the temperature of the tip (ambient temperature, without turn on the heating) but I get a lot of noise and the temperature value is not stable.
I'm acquire 10 samples each time to calculate the average but did not help much.
If I increase the capacitors in the input and output of the amplifier it stabilize, but in that way it is necessary a lot of time for the capacitors discharge between turning off the heater and start reading the temperature
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Project logs / Re: HAKKO (907ESD) and SOLOMON (SL-10/30) soldering iron dri
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Project logs / Re: My HAKKO classic and T12/T15 soldering controller
I realized that the heater is on or off during the whole mains period. That is, you do not use a PWM with a fixed period and varying on and off times, right?
If I use a common PWM the interval between each PID calculation should be at least greater than one PWM period?
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Project logs / Re: My HAKKO classic and T12/T15 soldering controller
What is your source for that PID algorithm?
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Project logs / Re: HAKKO (907ESD) and SOLOMON (SL-10/30) soldering iron dri
From the standard types of thermocouples the N type is the closest, but even so the error is too large.
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Project logs / Re: HAKKO (907ESD) and SOLOMON (SL-10/30) soldering iron dri
I understand now.
But I think it is preferable to perform all the tip control by the MCU.
Turning the tip voltage off in the periods defined to make the measurements.
Probably also because in this way one can reduce the time that the MOSFET is turned off from 1 ms to 500us (for voltage stabilization) + some us to the ADC acquire.
yes to be precise the temperature sensor should be in the T12 terminals, but the temperature in the control box should not be very different and should be more accurate than without sensor because the ambient temperature can be quite different than 22°C
I did not know the self-zeroing opamps but it seems be a good option for this case.
I saw your video and I was impressed with the result.
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Project logs / Re: HAKKO (907ESD) and SOLOMON (SL-10/30) soldering iron dri
I have some questions:
why the 25V dc is not filtered? you can save some components in the back.
I have seen that the T12 tips have a N type thermocouple. Do try to verify if it fits with the N type tables?
The C9 should not be greater due to the large noise that should be when the voltage is turned off?
I don't see a ambient temperature sensor. How do you compensate the TC cold junction?
About the sleep sensor, I think there is no need to complicate :)