Brymen BM857

Brymen BM857

Status	planned
Counts	50000, 500000(DCV), 999999(Hz)
IEC 61010-1	CAT III (1000V) / CAT IV (600V)
Connectivity	RS232
Measurements	voltage, frequency, diode, resistance, continuity, capacitance, current
Features	autorange, data hold, crest, backlight, true-rms
Website	brymen.com

The Brymen BM857 is a 50000 counts (500000 DC), CAT III (1000V) / CAT IV (600V) handheld digital multimeter with RS232 connectivity.

Hardware

Multimeter:

• Multimeter IC: TBD
• Precision +2.5V Voltage reference: Analog Devices REF43
• True RMS-to-DC converter: Analog Devices AD737
• EEPROM(?): Chip marked S24C0.
• Unidentified: Several 062-JRC chips. These appear to be JFET opamps.
• Unidentified: Two QFP64 chips.
• TODO

Cable:

• TODO

See User_talk:Mrnuke#BM857_PC_Interface_cable

Photos

Multimeter:

• 

  Box

• 

  Mughsot

• 

  Device, back

• 

  Package contents

• 

  Probe cable storage clips

• 

  LCD Backlight

• 

  Holster removed, front

• 

  Holster removed, back

• 

  Case opened

• 

  Rear cover

• 

  Front cover

• 

  Rear cover, PCB removed

• 

  Upper PCB, top

• 

  Upper PCB, bottom

• 

  Main PCB, top

• 

  Main PCB, bottom

• 

  High voltage isolation slots.

• 

  High voltage isolation walls, designed to fit in the isolation slots.

• 

  Input circuit near the V jack

• 

  Microcontroller (right), and LCD controller (left)

• 

  Microcontroller (right), and LCD controller (left)

• 

  LCD controller and connector

• 

  ICs on the main PCB

• 

  More ICs

Cable:

We don't have the BC-85X cable for this device. The BC-85Xa, which we tried, is not compatible this multimeter. The BC-85-1 seems to work acceptably well.

Currently, mrnuke is working on an improvised USB-to-infrared converter for development purposes. If you have a BC-85X you'd like to donate, contact mrnuke on #sigrok. See User_talk:Mrnuke#BM857_PC_interface_cable for more details.

Protocol

TODO

Resources

TODO