Brymen BM857
 | |
| 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 |
| 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:
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