HYELEC MS8236

HYELEC MS8236

Status	planned
Counts	6000
IEC 61010-1	CAT III (1000V) / CAT IV (600V)
Connectivity	USB
Measurements	voltage, resistance, diode, capacitance, frequency, current, hFE, temperature
Features	autorange, true-rms, data hold, delay hold, min/max, relative, bargraph, backlight
Website	hy-elec.com

The HYELEC MS8236 is a 6000 counts, CAT III (1000V) / CAT IV (600V) handheld digital multimeter with USB connectivity.

See HYELEC MS8236/Info for more details (such as lsusb -v output) about the device.

Hardware

• 8-bit MCU with 4x40 LCD driver and 18-bit ADC: Hycontek HY11P14 (datasheet, user's guide)
• USB to serial IC: WCN CH340G (datasheet)

Photos

Multimeter:

• 

  PCB, top

• 

  PCB, bottom

• 

  USB interface

USB cable:

Standard USB to miniUSB.

Protocol

TODO.

The device's LCD segments are layed out as follows:

	G
C		F
	B
A		E
	D

To the left of each LCD digit there is another segment which represents a dot / decimal point (DP).

An LCD segment is represented in the protocol as follows:

Bit 7	Bit 6	Bit 5	Bit 4	Bit 3	Bit 2	Bit 1	Bit 0
DP	A	B	C	D	E	F	G

Example: In the protocol a byte of 0x3F (0 0111111) represents the digit 9 on the LCD, where the decimal point is not displayed (bit 7 is not set). All other bits except for bit 6 (segment A, see above) are set, i.e. the respective LCD segments are displayed.

The meter have an NCV icon but the function is not documented on the manual, I wasn't able to trigger it, it's probably not implemented. Everything with a (?) after is doubtful or impossible to confirm.

Protocol consists of 22 bytes:

Bytes 1 to 6: Always AA 55 52 24 01 10 . Probably some kind of header to test if transmission is ok, as the protocol doesn't have any kind of CRC.

Bytes 7 to 10: Next four bits are the big LCD numbers, from right to left, in the format already specified by uwe_ on the wiki.

Byte 11: 00000000 -> Diode icon

        |||||||---> AC
        ||||||----> DC
        |||||-----> - 
        ||||------> - (yeah, both bits set to 1 when displaying "minus")
        |||-------> "Progess bar cue" -the bar with the 0 - 10 - 20 - ...
        ||--------> Continuity tester "sound" icon
        |---------> Battery

Bytes 12 to 18: that "progress bar on the top". Dunno what's its use, probably we can ignore it

Byte 19: 00000000 -> More progress bar thingy

        |||||||---> More progress bar thingy
        ||||||----> More progress bar thingy
        |||||-----> More progress bar thingy
        ||||------> Wait... (?) (Never shown on the PC but as it is a LCD protocol probably goes mapped here internally even if it never get transmited to the PC)
        |||-------> Auto
        ||--------> HOLD (?) (USB transmission seems to stop when Hold is activated)
        |---------> REL

Byte 20: 00000000 -> USB Icon (Of course, always on)

        |||||||---> MAX
        ||||||----> - (between MAX and MIN)
        |||||-----> MIN
        ||||------> N/A (?)
        |||-------> %
        ||--------> hFE
        |---------> N/A (?)

Byte 21: 00000000 -> C

        |||||||---> F (temp)
        ||||||----> N/A (?)
        |||||-----> N/A (?)
        ||||------> m (in the Farads line)
        |||-------> u (in the Farads line)
        ||--------> n (in the Farads line)
        |---------> F (Farads)

Byte 22: 00000000 -> u (in the A line)

        |||||||---> m (in the A line)
        ||||||----> A
        |||||-----> V (in diode meter mode)
        ||||------> M (in the Ohms line)
        |||-------> k (in the Ohms line)
        ||--------> Ohms
        |---------> Hz

Resources

• Random aliexpress.com sellers
• Disassembly video