arc19
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Joined: Mon Jul 08, 2019 1:59 pm

Thermocouple vs Temperature Sensors

Thu Jul 11, 2019 3:38 pm

Hi, just a general question: I want to detect values from a generator. What's the difference between using thermocouple or temperature sensors?

LTolledo
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Re: Thermocouple vs Temperature Sensors

Thu Jul 11, 2019 9:07 pm

thermocouple is a contact temperature sensor
temperature sensors may be in form of thermocouple, infrared, etc

google around to get a better answer!
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omegaman477
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Re: Thermocouple vs Temperature Sensors

Fri Jul 12, 2019 11:57 am

arc19 wrote:
Thu Jul 11, 2019 3:38 pm
Hi, just a general question: I want to detect values from a generator. What's the difference between using thermocouple or temperature sensors?
When you say temperature sensor, I assume you mean a digital style DS18B20 style chip sensor, but here is the run down.
When I speak of Thermocouples, the same generally applies to PTR's.

Thermocouples need precise amplifiers and ADC circuits to be read by the RPI. There are many Thermocouple hats available.
Thermocouples are far more rugged, and offer wider temperature ranges. Most digital sensors max out at 125C. Thermocouples can go to several thousand C. If this is a combustion engine generator, then the high temperature range will probably demand a thermocouple.
There is a thermocouple style for every application (bolt, pipe, oil pan, fuel line, bearing, exhaust manifold, turbo shaft) Chip sensors tend to be very limited in their mechanical mounting options.
Digital sensors are easy to interface, i2C sensors just need power and 1 wire, and the RPI will read them natively. Thermocouples will need a ADC hat etc.
Both have limitations over cable distance from the sensor to the controller
Digital sensors usually read quicker, and usually are cheaper, for smaller projects
Digital sensors claim to be calibrated, but often do need calibration. Thermocouples will need calibration generally.
Thermocouple wiring is specialised. Extension cables must be of special type and use the correct termination and connectors.
For an engine generator, you will find thermocouples moe reliable and robust. But digital sensors are much easier to interface for the hobbiest.
..the only thing worse than a stupid question is a question not asked.

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rpdom
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Re: Thermocouple vs Temperature Sensors

Fri Jul 12, 2019 12:13 pm

omegaman477 wrote:
Fri Jul 12, 2019 11:57 am
Digital sensors are easy to interface, i2C sensors just need power and 1 wire, and the RPI will read them natively.
Sensors that use the Dallas 1-wire bus just need power and 1 wire for data.

i2c sensors need power and 2 wires, one for data and one for clock.

arc19
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Joined: Mon Jul 08, 2019 1:59 pm

Re: Thermocouple vs Temperature Sensors

Fri Jul 12, 2019 3:13 pm

Thank you omegaman477! I was having trouble understanding things online and you cleared it up for me very simply.

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