Once you determine the type of thermocouple you need for your application, the decisions aren’t over. The last decision to make is the type of connector to be used; mini-plug, screw terminal or terminal block. Each type of connector has different benefits depending on your needs.
Also known as a sub-miniature plug or SMP, a mini-plug connector is the most common, and easiest connection type for thermocouples. These connectors are prewired into a plug which is simply plugged into the terminal. Each connector will have a positive and negative male connector which will plug into the female connector for quick, fail-proof installation. As an added bonus, the mini-plugs are color-coordinated, so you will always be able to tell the type TC you are using with a quick glance.
Unlike the simple plug-and-play nature of mini-plugs, screw terminal connectors attach bare wire to the circuit board of the data logger. For a product like the TC101A, Simply insert the wires into the correct slot and tighten the screw terminal. Once connected, the thermocouple can not be removed from the data logger without reopening the case. Although slightly more work, bare wire thermocouples tend to be less money than mini-plugs.
Combining the two connector types above results in your third option: terminal blocks. This approach takes a bare wire thermocouple and screws into a terminal block, which can then be connected to the data logger. There is again a cost-saving associated with this approach, although, as with screw terminal connections, it is important to take note of the polarity of the thermocouples, as incorrect wiring will lead to inaccurate readings.
At the end of the day, choosing which type of thermocouple connection to use is a personal preference. When wired correctly, all three options should perform the same. For more information on thermocouples and their connections to data loggers, contact MadgeTech at [email protected] or (603) 456-2011.