The conductors are protected from the environment, enabling the sensor to be used in a wider range of applications.

thermocouple interface with no issues as long as the type is also supported. Ungrounded thermocouples can be used with a Phidgets Inc. As a result, it will take longer for the thermocouple to react to temperature changes in the environment, because the inside of the sheath must reach thermal equilibrium before the conductors can detect the change. The junction where the two conductors meet is suspended inside this sheath, such that the end of the junction is not in contact with the sheath. There are three main types of junctions: Grounded, Ungrounded, and Exposed.Ī thermocouple with an ungrounded junction has a metallic outer sheath, usually made of a corrosion-resistant material such as stainless steel. This describes the degree to which the sensing end of the thermocouple is exposed to the environment it's measuring.

Add the two voltage values from the previous steps and use the table to convert back into temperature.Ī cross-sectional view of the three most common junction types.Īn important feature to consider when choosing a thermocouple is the junction type.

Open your Phidget's thermocouple output in VoltageInput mode and read the Voltage property in your program (see the Phidget22 API for details) in order to get the thermocouple's current thermoelectric voltage value.

Record this thermoelectric voltage value.

Take the ambient temperature value measured by the board and use the ones digit to select the column, and the other digits to select the row.

First, visit this website and open the conversion table for the desired thermocouple type.

thermocouple interfaces, with some minor calculations: You can interface with other thermocouple types using Phidgets Inc. Using Other Thermocouple Types with Phidgets For short durations the thermocouples can be exposed to higher heat than they are rated for, however, they will degrade if exposed to very high heat for long periods of time. The same thermocouple using Fiberglass is good to 480☌. For example, a K-type thermocouple insulated with teflon is good up to +200☌. The insulation that surrounds the thermocouple is the limiting factor in the true temperature range. Well suited to low temperature (cryogenic) use Most Accurate base-metal thermocouple, non-magnetic, popular choice for strong magnetic fields and subzero environments More Limited range, main application is with old equipment that cannot accept modern thermocouples The most common sensor, wide range, good in oxidizing atmosphere

Each type has a different temperature range and resolution due to the metals used in the conductors. J, K, E and T-Type thermocouples are the most common types of thermocouples. Most thermocouples produce voltages of less than 50mV so very sensitive electronics are required to interface with them.Ĭhoosing a Thermocouple Conductor Calibration Types There are many types of thermocouples, with varying types of conductors and probe designs. A thermocouple is a device consisting of 2 different conductors that produce a voltage proportional to a temperature difference between either end of the pair of conductors.

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