UNI-T UT61E

UNI-T UT61E

Status	in progress
Counts	22000
IEC 61010-1	CAT II (600V) / CAT III (300V)
Connectivity	RS232 / USB
Measurements	voltage, current, resistance, capacitance, frequency, duty cycle, diode, continuity
Features	autorange, true-rms, data hold, min/max, relative, bargraph, backlight
Website	uni-trend.com

The UNI-T UT61E is a 22000 counts, CAT II (600V) / CAT III (300V) handheld digital multimeter with RS232 or USB connectivity.

See UNI-T UT61E/Info for more details (such as lsusb -vvv output) about the device.

Hardware

• Cyrustek ES51922 multimeter chip (ES51922A actually, as per various photos: 1, 2, 3, 4)

Photos

Older version:

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Newer version:

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Protocol

See Multimeter_ICs#Cyrustek ES51922 for the DMM IC protocol.

Depending on the cable, additional decoding is needed, though.

TODO: Serial cable vs. the two USB HID based cables.

The transmission of the measurement data cannot be disabled, the respective Cyrustek ES51922 pin (111, RS232) is tied to GND (i.e. transmission is always enabled) on this multimeter.^[1]

Resources

• Manual
• Vendor software
• Henrik Haftmann: DMM.exe etc. (Windows software for various UNI-T DMMs, and lots of device/protocol info)
• Henrik Haftmann: Hoitek HE2325U info
• Henrik Haftmann: UT61E log and protocol docs
• diyftw.de: Uni-Trend UT61E (UT-D04 linux treiber) (device info, Linux software using HIDAPI: ut61e-linux-sw-0.02.tar.gz)
• Steffen Vogel: UNI-TREND UT61E Digital Multimeter (device info, Linux software for serial port: dmmut61e-0.01.tar.gz)
• Steffen Vogel: Inner workings of UNI-TREND UT61E Digital Multimeter (teardown)
• erste.de: UT61 - USB Multimeter unter Linux auslesen (info on the Hoitek HE2325U (clone?) and how suspend/resume fixes some issues with it)
• easyelectronics.ru: Refinement of a file multimeter UT61E
• flodins.info: Multimeter UNI-T UT61E
• UNI-T UT61E schematics: ut61e sch.pdf
• Teardowns: 1, 2, 3, 4, 5, 6