Digital multimeter module

Beckhoff has added enhanced measurement technology functions to its I/O system, by incorporating a digital multimeter module. Using the digital multimeter with fieldbus interface for measuring current and voltage, measured values can be processed directly in the I/O system or by the master controller. These dynamic measuring terminals are available for both the Beckhoff bus terminal system and for the EtherCAT Terminal system.

Utilising a powerful CPU, ultra-fast communication (eg, via EtherCAT), real-time software and an I/O interface to the outside world, Beckhoff PC-based control technology offers a suitable system for high-precision, high-speed measuring equipment. The use of the Beckhoff KL3681 (bus terminal) and EL3681 (EtherCAT terminal) significantly increases flexibility thanks to the wide input range and automated measuring range selection. High precision and simple, high-resistance measurement from 30 mV to 300 V allows the bus terminal to be used like a digital multimeter.

In measuring applications in particular, the expected voltage is often not known during the planning phase. Automatic adjustment of the measurement range simplifies use and reduces stock levels. The digital multimeter terminals measure DC and RMS AC voltages.

Good immunity to interference is achieved via the complete galvanic isolation of the electronic measuring system and a measurement interval of typically 200 ms. The measured result is equivalent to that of a good handheld multimeter, but the bus terminal also has an interface to all common fieldbuses via which it can be read out and parameterised.