UNI-T UT61E

UNI-T UT61E

Status	supported
Counts	22,000
IEC 61010-1	CAT II (600 V) / CAT III (300 V)
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 22,000 counts, CAT II (600 V) / CAT III (300 V) handheld digital multimeter with RS-232 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

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Newer version:

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Protocol

See Cyrustek ES51922 for the DMM IC protocol.

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

Different cables are available to communicate to the DMM: regular serial cables which provide a COM port, and USB HID based cables where applications are required to handle a proprietary protocol of running serial communication on top of HID requests. See the Device cables page for details; the same cables can be used with many different DMM models.

Depending on the specific cable in use, either a device driver ending in -ser or not ending in -ser must be used. See README.devices for details.

The message "HID feature report error: LIBUSB_ERROR_PIPE" results from using the USB HID driver with a USB-to-serial cable. In this case, try using --driver=uni-t-ut61e-ser

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]

Usage

The following sigrok-cli command can be used to receive five measured values from a device connected via USB (note that the USB VID/PID after the conn option needs to be changed depending on the exact USB adapter cable used):

$ sigrok-cli --driver=uni-t-ut61e:conn=1a86.e008 -O analog --samples 5

If your meter has a serial (RS-232) cable connected to a USB-to-serial adapter, a different driver is used. Example for ttyUSB0:

$ sigrok-cli --driver=uni-t-ut61e-ser:conn=/dev/ttyUSB0 -O analog --samples 5

Same example for COM1 (Windows), please note the special syntax for specifying the COM port:

C:\> sigrok-cli --driver=uni-t-ut61e-ser:conn=\\.\COM1 -O analog --samples 5

--samples <n> stops acquisition after the specified number of measurements, while --continuous does not stop. Type just sigrok-cli by itself for a summary of options. More information on drivers can be found in the README.devices file of the libsigrok source tree.

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)
• Multimeter data parsing utility complete implementation written in Python
• 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