Metrix MX56C

**Metrix MX56C**
Status	supported
Source code	serial-dmm
Counts	50000
IEC 61010-1	CAT III (600V)
Connectivity	RS232
Measurements	voltage, resistance, diode, continuity, capacitance, frequency, duty cycle, pulse count, current, power, gain
Features	autorange, hold, relative, bargraph, backlight, true-rms, AC+DC
Website	chauvin-arnoux.com

The Metrix MX56C is a 50000 counts, CAT III (600V) handheld digital multimeter with RS232 connectivity.

The same device was also sold as BK Precision 5390.

Hardware

The vendor specifically announces the high IP rating, and the advanced safety features. The labelling suggests that "ASYC" stands for "Advanced Safety Concept". Some models "lock" the probes, such that special action needs to be taken before they can get unplugged. The battery and fuse compartment only can get accessed after the probes were removed.

The tilt stand at the back of the device can get removed, and then be used as a tool to open the front cover. The locations for the tool during this activity are marked. Removing the front cover allows access to the battery and the fuses. The tool can be used to further open the device and remove the back cover as well, to access the PCB inside the meter. But that activity is not suggested, and is not needed for regular use.

The location of the IR LEDs is rather unusual -- right underneath the range selector, within the battery compartment. This is especially annoying as the meter has a high IP rating, which results in extra covers for improved isolation from environmental influences. A special kit is sold for serial communication, which includes an alternative cover that replaces the originally shipped cover around the range selector.

(No further hardware details here, neither teardown images -- see the EEVblog link in the resources section. Images there show a DMM chip labelled "ITT" and "METRIX DMM5", and a flyer for the serial communication kit. User "free_electron" provides background on the ITT corporation.)