UNI-T UT612

From sigrok
Jump to navigation Jump to search
UNI-T UT612
Ut612-front-mugshot.png
Status supported
Source code serial-lcr
Counts 20000
IEC 61010-1
Connectivity USB (HID)
Measurements resistance, capacitance, inductance, equivalents
Features autorange, rel, data-hold, auto-poweroff, self-calibration
Website uni-trend.com

The UNI-T UT612 is a 20000 counts, dual-display, LCR meter with USB/HID connectivity.

See UNI-T UT612/Info for more details (such as lsusb -v output) about the device.

The LCR meter uses the popular ES51919/ES51920 chipset, but with the SiLabs CP2110 USB HID communication chip instead of USB CDC and a regular COM port. Libsigrok's serial layer supports either type of connection.

Hardware

The ES51919/51920 chipset is found in other LCR meters, too. The chipset communicates via UART (TX only).

The CP2110 USB serial-over-HID chip resides on a separate breakout board, and is connected to the LCR "mainboard" via a three wire flying cable. Red(!) is GND, green is the meter's TX signal, RX is not connected, yellow is Vcc from USB.

Photos

Protocol

The protocol for the ES51919 was reverse engineered as part of the DER-EE 5000 driver that uses the same chipset. Below is the excerpt from the source code.

Public official documentation does not contain the protocol description, so this is all based on reverse engineering.

Packet structure (17 bytes):

0x00: header1 ?? (0x00)

0x01: header2 ?? (0x0d)

0x02: flags
        bit 0 = hold enabled
        bit 1 = reference shown (in delta mode)
        bit 2 = delta mode
        bit 3 = calibration mode
        bit 4 = sorting mode
        bit 5 = LCR mode
        bit 6 = auto mode
        bit 7 = parallel measurement (vs. serial)

0x03: config
        bit 0-4 = ??? (0x10)
        bit 5-7 = test frequency
                    0 = 100 Hz
                    1 = 120 Hz
                    2 = 1 kHz
                    3 = 10 kHz
                    4 = 100 kHz
                    5 = 0 Hz (DC)

0x04: tolerance (sorting mode)
        0 = not set
        3 = +-0.25%
        4 = +-0.5%
        5 = +-1%
        6 = +-2%
        7 = +-5%
        8 = +-10%
        9 = +-20%
       10 = -20+80%

0x05-0x09: primary measurement
  0x05: measured quantity
          1 = inductance
          2 = capacitance
          3 = resistance
          4 = DC resistance
  0x06: measurement MSB  (0x4e20 = 20000 = outside limits)
  0x07: measurement LSB
  0x08: measurement info
          bit 0-2 = decimal point multiplier (10^-val)
          bit 3-7 = unit
                      0 = no unit
                      1 = Ohm
                      2 = kOhm
                      3 = MOhm
                      5 = uH
                      6 = mH
                      7 = H
                      8 = kH
                      9 = pF
                      10 = nF
                      11 = uF
                      12 = mF
                      13 = %
                      14 = degree

0x09: measurement status
          bit 0-3 = status
                      0 = normal (measurement shown)
                      1 = blank (nothing shown)
                      2 = lines ("----")
                      3 = outside limits ("OL")
                      7 = pass ("PASS")
                      8 = fail ("FAIL")
                      9 = open ("OPEn")
                     10 = shorted ("Srt")
          bit 4-6 = ??? (maybe part of same field with 0-3)
          bit 7   = ??? (some independent flag)

0x0a-0x0e: secondary measurement
  0x0a: measured quantity
          0 = none
          1 = dissipation factor
          2 = quality factor
          3 = parallel AC resistance / ESR
          4 = phase angle
  0x0b-0x0e: like primary measurement

0x0f: footer1 (0x0d)

0x10: footer2 (0x0a)

Resources