Difference between revisions of "Brymen BM857"
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Currently, mrnuke is working on an improvised USB-to-infrared converter cable. See [[User_talk:Mrnuke#BM857_PC_interface_cable]] for more details. | Currently, mrnuke is working on an improvised USB-to-infrared converter cable. See [[User_talk:Mrnuke#BM857_PC_interface_cable]] for more details. | ||
Newer models (BM850a/BM850s) are said to require the BU-85Xa adapter. These different versions of meters and adapters are not compatible to each other. | |||
<gallery> | <gallery> | ||
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== Protocol == | == Protocol == | ||
Serial communication (genuine COM port), textual presentation of measurement values (floating point, normalized mantissa plus exponent), number codes for current meter's function and thus measured unit, variable length records with control chars in the header/footer (DLE, STX/ETX) around the mode number and value's text, up to 22 bytes per DMM packet. See resources below for a full description of the protocol. | |||
== Resources == | == Resources == | ||
[http://brymen.com/product-html/PD02BM850s_protocolDL.html] [http://brymen.com/product-html/images/DownloadList/ProtocolList/BM850-BM850a-BM850s_List/BM850-BM850a-BM850s-500000-count-DMM-protocol-BC85X-BC85Xa.zip] BM850/BM850a/BM850s protocol documentation, download area and download file (ZIP with PDF, worked as of 2019-06-10) | |||
[[Category:Device]] | [[Category:Device]] | ||
[[Category:Multimeter]] | [[Category:Multimeter]] | ||
[[Category:Supported]] | [[Category:Supported]] | ||
Revision as of 10:20, 10 June 2019
 | |
| Status | supported |
|---|---|
| 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:
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:
This can use either the BC-85X or the BC-85X-1 cables. See Device_cables#Brymen_BC-85X(-1).
Currently, mrnuke is working on an improvised USB-to-infrared converter cable. See User_talk:Mrnuke#BM857_PC_interface_cable for more details.
Newer models (BM850a/BM850s) are said to require the BU-85Xa adapter. These different versions of meters and adapters are not compatible to each other.
Cable hookup
Cable hookup, detail
Cable hookup, closeup
Cable hookup, top detail
Protocol
Serial communication (genuine COM port), textual presentation of measurement values (floating point, normalized mantissa plus exponent), number codes for current meter's function and thus measured unit, variable length records with control chars in the header/footer (DLE, STX/ETX) around the mode number and value's text, up to 22 bytes per DMM packet. See resources below for a full description of the protocol.
Resources
[1] [2] BM850/BM850a/BM850s protocol documentation, download area and download file (ZIP with PDF, worked as of 2019-06-10)