ESP8266 Community Forum

- Sat Oct 27, 2018 3:23 pm #78911

I can't say what is best for you. I prefer thermocouples as that is what I am familiar with. The processes that i have dealt with had thermocouples originally so I stuck with it. Thermocouples need to be connected with thermocouple wire of the same type. The resistance of the wire connecting the RTDs is a factor that needs to be considered. With thermocouples resistance is not significant.

In the end the choice is always a consideration of many factors.

If you are considering thermocouples then look at MAX31856. It would be my first choice in a new design.
https://www.adafruit.com/product/3263

https://www.aliexpress.com/item/MAX3185 ... 82894.html

I understand, your best case is thermocouple! I'm also facing this, meeting some customers but still can not tell when they both have 2 strands, they look pretty. Perhaps there is a difference between their resistance that characterizes each one.
Very good the chips, it is easy to confuse, because the names are very similar between the MAX that le PT100 and what thermocouple.
I did not find here in my country to buy the MAX31856, I found the MAX6675. Do you know the difference between them? I will use commercial to automate some things, I must begin to take one that I will buy in greater quantity.

- Sat Oct 27, 2018 4:40 pm #78912 MAX6675 Cold-Junction-Compensated K-Thermocouple-to-Digital Converter (0°C to +1024°C)
The MAX6675 is an older part compared to the others.

Honestly, all the answers I gave you, you could have found this information by doing a simple search. I don't mind helping if I can, but why should I spend the time to look for information when the person with the project doesn't make a little effort.

- Sat Oct 27, 2018 8:18 pm #78916

MAX6675 Cold-Junction-Compensated K-Thermocouple-to-Digital Converter (0°C to +1024°C)
The MAX6675 is an older part compared to the others.

Honestly, all the answers I gave you, you could have found this information by doing a simple search. I don't mind helping if I can, but why should I spend the time to look for information when the person with the project doesn't make a little effort.

So, I've done some research for some time ... I've been researching but I think it's just an absurdly expensive solution. It is not lack of effort. I am currently using Novus TxMini. But I am dissatisfied with the price and the difficulty of use. As you wanted to help, I asked a few questions. People who use the most time, have more tips and experience to share. I figured it was not a problem to ask. It is the first solution that I think for thermocouple and for pt100 with affordable price and compatible protocol. Previously the best I got was a Modbus converter that costs something around 70 dollars.
Thank you for your help!
I'll follow your tips!

Tks Rudy

- Sun Oct 28, 2018 2:09 am #78919 Sine you are developing this solution for a specific customer, why not price-up each option with pros/cons and give this to the customer as an R&D assessment of what they have to choose from; it is then their choice as to cost.