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Precision analog measurement module from KNESTEL for measurement in the high-voltage range

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Precise measurement, decentralized, low temperature drift and all this under high voltage? With the development of a precision measurement module completed in 2021, this is all possible..

With our newly developed PAM (Precision Analog Measurement Module), we have oriented ourselves to the requirements of electromobility. The use in charging technology or in component tests of batteries, with the technology of the PAM both is possible.

However, the modular nature of the measuring module offers a variety of other possible applications. Voltages, currents and temperatures can be recorded decentrally with the device. The measured values are transmitted via CAN bus or EtherCAT. Depending on the requirements, several modules for voltage, current and temperature measurement can be added to the control module. For use in the high-voltage range, DIN EN 61010-1 was taken into account during development.

The measuring inputs are galvanically isolated from ground, the power supply and the communication interface. In addition, overvoltage protection up to 2.5kV is provided. The isolation voltage is greater than 3kV. Under these conditions voltage measurements up to 1000V are possible, the offset and scaling error is 50mV.

During development, care was taken to keep the measurement error as low as possible in the event of a change in ambient temperature in order to make the measuring device independent of the place of use. Even if the temperature in the control cabinet rises at high powers, the measured value only drifts by a maximum of 8ppm per Kelvin temperature change.

In order to be able to measure the large currents, which arise for example during the charging process of a battery, almost loss-free, a Hall sensor is used. The voltage supply for this can be provided by an integrable module via the PAM. The Hall sensor is connected to the current measurement module via a Sub-D connector.

In order to monitor the temperature of the DUT during an end-of-line test, an integratable module for temperature monitoring using PT100/PT1000 resistors was developed. With the technologies used, we are able to adapt the PAM to many different applications and to flexible customer requirements. Wherever precise and decentralized measurement is required in a high-voltage environment and under fluctuating temperatures, our PAM can be used. Our PAM has even been commissioned with control tasks. During bidirectional charging with our intelligent buck converter bridges, a setpoint for current and voltage is specified via CAN. The networked PAM takes over the control. It receives the feedback via its own current and voltage measurement modules.