Voltcraft VC-840
 | |
| Status | supported |
|---|---|
| Source code | serial-dmm |
| Counts | 4000 |
| IEC 61010-1 | CAT IV (600V) |
| Connectivity | RS232 / USB |
| Measurements | voltage, capacitance, continuity, diode, frequency, temperature, current, duty cycle |
| Features | autorange, true-rms, hold, relative |
| Website | conrad.de |
The Voltcraft VC-840 is a 4000 counts, CAT IV (600V) handheld digital multimeter with RS232 or USB connectivity.
Hardware
Multimeter:
- Multimeter IC: Fortune Semiconductor FS9721_LP3 (datasheet)
- Low power, True RMS-to-DC converter: Analog Devices AD737J (datasheet)
- Unknown SO-8 chip: ?
- Crystal: likely 4MHz (not verified, though)
- Fuses: 10A/250V and 500mA/250V (one glass fuse, one HRV fuse)
RS232 cable:
USB cable:
Photos
Multimeter:
Device, front
Device, back
Device, back w/o battery
Battery 1
Battery 2
PCB, front
PCB, back
Analog Devices AD737J
Fortune Semi. FS9721_LP3
RS232 cable:
See Device cables#UNI-T_UT-D02.
USB cable:
See Device cables#UNI-T_UT-D04.
Protocol
See Multimeter_ICs#Fortune_Semiconductor_FS9721_LP3 for the DMM IC protocol.
Depending on the cable, additional decoding is needed, though.
TODO: Serial cable vs. the two USB HID based cables.
A short protocol description is also available from Voltcraft/Conrad. And another one.