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2X MAX31850K from adafruit #222

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elmenno opened this issue Jan 7, 2022 · 11 comments
Open

2X MAX31850K from adafruit #222

elmenno opened this issue Jan 7, 2022 · 11 comments

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@elmenno
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elmenno commented Jan 7, 2022

I have 2x the adafruit MAX31850K https://www.adafruit.com/product/1727

i connecting the date to date en v3.3 to v3.3 en GND to GND

its te same situation as used by Werner Johansson https://github.com/UnifiedEngineering/T-962-improvements/wiki/Better-thermocouple-interface
IMG_20220107_173230
IMG_20220107_173227

Can somebody help me out please?
IMG_20220107_172907

same temp readings
See the pictures

@xnk
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xnk commented Jan 7, 2022 via email

@elmenno
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elmenno commented Jan 7, 2022

Realy thanks for the quick replay now i am happy
the cold juction temp works the DS18B20

Do you mean this? see pict
qwqw
ure red marking is for soldering

i go soldering now the correct voltage super thanks Werner

@elmenno elmenno closed this as completed Jan 7, 2022
@elmenno elmenno reopened this Jan 7, 2022
@elmenno
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elmenno commented Jan 7, 2022

I hope it wil work now (-:

@xnk
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xnk commented Jan 7, 2022 via email

@elmenno
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elmenno commented Jan 7, 2022

Werner super thanks for the fast replay

Now it working great for so far now i gong testing the oven
see the picture
IMG_20220107_225443

Greeting Menno

@xnk
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xnk commented Jan 7, 2022 via email

@borland1
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Menno,

Since the MAX31850 chip incorporates internal Cold-Junction temperature compensation, does the UnifiedEngineering TC-961 firmware take this into account? Did you subsequently remove the DS18B20? Seem unnecessary with the MAX31850's being used.

@GitLang
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GitLang commented Aug 28, 2022

The DS18B20 is now used to monitor the electronics enclosure temperature and (I think) control the very small fan for that enclosure.

@borland1
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borland1 commented Aug 28, 2022

GitLang,

The small 12V DC fan is connected directly to the power supply, so normally this small fan runs at one speed. The wiki describes a circuit board mod, using a transistor switch, to add processor control of this fan.

The firmware of this repository adjusts the oven thermocouple temperature by adding, if detected, the DS18B20 reported temperature. With the two MAX31850's, which have there own internal cold junction compensation, I'm not sure about how this UE firmware handles the compensation calculation.

This code snippet from the sensor.c file.

coldjunction = OneWire_GetTempSensorReading();  <--
		if (coldjunction < 127.0f) {
			cjsensorpresent = 1;
		} else {
			coldjunction = 25.0f; // Assume 25C ambient if not found
		}
		temp[0] = ADC_Read(1);
		temp[1] = ADC_Read(2);

		// ADC oversamples to supply 4 additional bits of resolution
		temperature[0] = ((float)temp[0]) / 16.0f;
		temperature[1] = ((float)temp[1]) / 16.0f;

		// Gain adjust
		temperature[0] *= adcgainadj[0];
		temperature[1] *= adcgainadj[1];

		// Offset adjust
-->		temperature[0] += coldjunction + adcoffsetadj[0];
-->		temperature[1] += coldjunction + adcoffsetadj[1];

		tempvalid |= 0x03;

		avgtemp = (temperature[0] + temperature[1]) / 2.0f;

@szenieh
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szenieh commented Aug 15, 2024

Ah I didn’t spot the address select dog bones on the bottom side. Leave a1 a2 and a3 at “0” on both boards and cut a0 from “0” and connect it to “1”. /wj

May I ask if your instruction to: "cut a0 from "0" and connect it to "1" " is for both boards or only for one of them? Thank you,

Salah Zenieh

@szenieh
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szenieh commented Aug 17, 2024

I also have 2x Max38150K from Adafruit- the same exact model as in this post. I am unable to get them to work. I have configured the address on one them to be 0 and on the other one to 1. The firmware does not recognize them. I have tested them with an Arduino and they work great. So, it must be a configuration issue so that the firmware can recognize them.

Should I configure them as 2 and 3? (making A0 (1, 0) and A1 (1,1)? Please help! Could elmenno describe how his worked?

Also, is how do I monitor the boot process via the programming header? Should I hook it up to a serial program like PuTTY? Will that work?

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