Thermocouple module ensures safer high voltage measurements

18th November 2014

Mick Elliott

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Datasheet

Hybrid and electric vehicles present entirely new challenges to the manufacturer's testing departments. There is new technology to embrace and an increased regard for safety aspects covering high voltage measurements. To meet these demands IPETRONIK's business division IPEmeasure has developed a compact high voltage thermocouple module for K-type sensors.

M-THERMO2 HV provides high versatility by offering 4 inputs for safe temperature measurement on high voltage potentials. It can easily be integrated into M2 systems and features quick configuration and data analysis in IPEmotion and in IPETRONIK data loggers.

Maximum personal protection is guaranteed by certified high-voltage thermocouples and cables. M-THERMO2 HV uses an enclosure of 106 mm x 73 mm x 60 mm in modern M2 design – performed under the terms of protection class IP65 and designed for direct application in the engine compartment. It operates in a temperature range of -40 °C to +105 °C. It requires 6 VDC to 36 VDC for power supply.

The power consumption typically is under 0.9 W. The temperature measuring range goes from -60 °C to +1370 °C and is digitalized per channel with a 24 bit analog/digital converter. The cold junction compensation takes place on the sockets of measurement inputs using RTDs (PT100 elements).

The adjustment of the A/D measuring chain is performed with each measurement acquisition. In order to achieve greatest possible accuracy, the sensor characteristic curve is numerically interpolated through an intern compensation algorithm. Accuracy at 25 °C ambient temperature is specified with ±0.035 % of the full temperature measuring range. The HV thermocouple module covers input voltage protection of ±50 VDC (indefinitely) and ±200 VDC (short-time). It supports channel sample rates of 1, 2, 5 and 10 minutes as well as 1, 2, 5, 10, 20, 50 and 100 Hz. In CAT I applications the permitted input voltage is 846 VDC, in CAT II applications it is 500 VAC at 50 Hz.

All the measurement inputs, CAN bus, power supply and enclosure are completely galvanically isolated up to isolation voltage of 846 VDC. Status LEDs on each measurement input inform about correct channel allocation or view sensor breaks in measurement operations. The data output occurs via CAN bus in accordance to ISO 11898-2 with up to 1 Mbit/s.

The measuring data has a 2 byte (16 bit) resolution with or without sign. The HV thermocouple module is available with two different connector types (Lemo sockets or thermosensor sockets). A separate HV safety socket is available for each input. A special fixing technique provides a combination of modules without a ny tools.