Brymen BM857

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Brymen BM857
Bm 857 mugshot 500000.png
Status progress
Source code brymen-dmm
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, dBmW1, %4-20mA
Website brymen.com

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

1: The reference impedance is selectable from 4Ω to 1200Ω. It is not limited to reference impedance of 600Ω.

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:

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