The TC30 is a low cost head mounted pt100 4-20 mA temperature transmitter that accepts RTD temperature sensors and all types of thermocouples and converts sensor output over a selected range into a 4 to 20 mA transmission signal. The transmitter is a two-wire, loop-powered device, and is fully configurable by the user, over a wide temperature range.
Head mount transmitter is in housed in the connection head of the sensor and thus the transmitter size is very compact. Moreover, it has minimal wiring because the transmitter is fitted in the head section of the sensor.
The conventional transmitter is mounted far from the sensor, and the additional precautions like lead wire compensation is required to minimize the measurement error. It also requires the long cable which incur additional cost. If the sensor is thermocouple type, then the additional thermocouple compensating cable is required.
However, in the case of head mount transmitter the lead wire compensation is not required as sensor and the transmitter is fitted in the same housing. As a result of this, the measuring accuracy of head mount transmitter is much better than the conventional 2 wire or 4 wire temperature transmitter.
If the head mount transmitter is used for thermocouple sensor, then no thermocouple compensation cable is required.

The 4 to 20 mA signal is a standard analog signal used in industrial instrumentation and control systems. It represents a range of values, where 4 mA corresponds to the minimum temperature measurement and 20 mA represents the maximum temperature measurement.