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in reply to: Ospid tc read problem, my input says error a lot #4078

I replaced the MAX31855 chip today and finally I´m not getting any input errors at all. Seems that the chip was broken…

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in reply to: Ospid tc read problem, my input says error a lot #4075

I have the same problem as you have. I already checked the ospid for poor solder points and tried out 5 different thermocouples.
But i found nothing, the error is still there.
I did a small workaround in the firmware, and I hope that works (didn´t debug/test yet)

double readThermistorTemp(int voltage)

{

static double oldTemp = -999;

static int cnt = 0;

float R = REFERENCE_RESISTANCE / (1024.0/(float)voltage - 1);

float steinhart;

steinhart = R / THERMISTORNOMINAL;     // (R/Ro)

steinhart = log(steinhart);                  // ln(R/Ro)

steinhart /= BCOEFFICIENT;                   // 1/B * ln(R/Ro)

steinhart += 1.0 / (TEMPERATURENOMINAL + 273.15); // + (1/To)

steinhart = 1.0 / steinhart;                 // Invert

steinhart -= 273.15;                         // convert to C



//eliminate big measurement error peaks

if((oldTemp != -999) && (abs(oldTemp - steinhart) > 10) && (cnt < 5))

{

steinhart = oldTemp;

cnt++;

}

else

{

cnt = 0;

oldTemp  = steinhart;

}



return steinhart;

}

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in reply to: Where can I find an osPID online? #4088

Hi,

take a look here: http://www.ospid.com/blog/buy/

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in reply to: Change To New User Permissions #4085

Great idea 🙂

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in reply to: Setpoint Profiles (for Reflow et al) #3823

@hairykiwi wrote:

What oven are you using? And what Profile and PID settings did you use?

It is a modified Severin TO 2035 with an additional 1500W heating element at the top, so now it has 3000W.
Also I modified the firmware (io.h) a bit, to use both relais at the same time.
Here is the profile:

JedecPB		//first row is Profile Name

3, 40, 0	//Step Setpoint to 40, wait 0 seconds

2, 0, 0		//Wait for PID Input to cross setpoint

1, 100, 60	//ramp setpoint to 100 over the course of 60 seconds

2, 0, 0		//Wait for PID Input to cross setpoint

1, 140, 90	//ramp setpoint to 140 over the course of 90 seconds

2, 0, 0		//Wait for PID Input to cross setpoint

1, 220, 80	//ramp setpoint to 220 over the course of 80 seconds

2, 0, 0		//Wait for PID Input to cross setpoint

1, 50, 150	//ramp setpoint to 50 over the course of 150 seconds

2, 0, 0		//Wait for PID Input to cross setpoint

3, 0, 0		//Step Setpoint to 0, wait 0 seconds

127, 0, 5	//buzz for 5 seconds

And my settings:
Kp: 15
Ki: 0.02
Kd: 0

To the temperature drop problem: I don´t think there is any loose connection outside or inside the osPID. I tried 3 different thermocouples and all of them had these little errors (randomly, some curves worked fine without an error, others with more than 5 errors). Also I can´t reproduce these error by wobbling the cables and/or osPID… It’s random…
Nevertheless i will check the solder points inside the osPID.

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in reply to: Setpoint Profiles (for Reflow et al) #3821

hello together,

I finally got my ospid yesterday and after some tuning I get fantastic curves (in this case i opened the door a bit too late):

I wonder why I get some temperature drops? I tried various K-Type and i get always these measurement-errors. Does anyone else get these errors?

Greetings from germany,
Tobias

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in reply to: Autotuning #3852

Hi guys,

after some trouble with the german customs i finally got my ospid controller today! It´s working so far (with big overshoot at default values), but i really don´t know how to use the AutoTune command.
I toggled to automatic control. After setting the setpoint, the oven started to heat. Then i activated the autotuner, but the oven is heating and heating and heating… I manually turned it off at >200 degrees.
Also I tried to wait for the oven-temperature is at 100 degrees and then turned on the autotune, but then i have the same problem. It will heat up to 200 degrees and greater.

What am i doing wrong? I really don´t understand that… can someone help me please?

Edit: I got it! Thanks anyway 🙂

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