Yokogawa CA450 process multimeter

The Yokogawa CA450 process multimeter is an on-site measuring instrument that not only offers the functionality of a digital multimeter for basic measurements such as voltage, current and resistance, but can also act as a calibrator for electrical and process measurements.

With specialised functions for repair, maintenance and troubleshooting of plant equipment, the multimeter is a single-unit, on-site measuring instrument that reduces the engineering load and improves plant efficiency by accomplishing tasks that have traditionally required two on-site measuring instruments.

The instrument is a true RMS digital multimeter with a basic measurement and generator accuracy of 0.05% and dedicated sensor modes for direct inputs from sensors such as AC/DC clamp probes. In addition, it incorporates a number of process-related features including loop check and 4-20 mA output generation and measurement functions.

With the loop check function, designed for tests on 2-wire transmitters, the instrument supplies 24 VDC power to the transmitter and measures the DC output in µA to an accuracy of 0.05% up to 30 mA. A HART mode with loop power and 250 Ω resistance allows HART and BRAIN communications to be tested. A transmitter simulator function allows transmitter I/O to be checked by drawing in (‘sinking’) designated currents from the external voltage generators of the instrumentation. The 4-20 mA generator output includes span, step, auto-step and sweep capabilities.

The device can also be used to carry out operating checks and adjustments on valve positioners, including zero and span adjustment, response testing using the auto-step function and tests for hunting, sticking/slipping and valve open/close errors. Controller programs can also be verified using its 4-20 mA step-generation function, which switches between 4 and 20 mA in 4 mA output steps.