Voltcraft VC-870
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Status | supported |
---|---|
Source code | serial-dmm |
Counts | 40000 |
IEC 61010-1 | CAT III (1000V) / CAT IV (600V) |
Connectivity | RS232 / USB |
Measurements | voltage, resistance, diode, continuity, capacitance, frequency, current, temperature, loop current, power + apparent power, power factor + frequency, effective voltage + current |
Features | autorange, hold, relative, backlight, min, max, minmax, true-rms, bargraph |
Website | conrad.de |
The Voltcraft VC-870 is a 40000 counts, CAT III (1000V) / CAT IV (600V) handheld digital multimeter with RS232 or USB connectivity.
Hardware
Multimeter:
We don't have teardown photos yet, but this article (see also this photo) claims that the DMM contains the following components:
- 4 3/4 and 5 3/4 digits ADC: Cyrustek ES51966 (datasheet)
- Microcontroller: Texas Instruments MSP430
- Voltage regulators: TPS76301, 7201u55
- EEPROM: Atmel "748"
- True RMS-to-DC converter: Analog Devices AD737 (datasheet)
RS232 cable:
USB cable:
Photos
Multimeter:
RS232 cable:
See Device cables#UNI-T_UT-D02.
USB cable:
See Device cables#UNI-T_UT-D04.
Protocol
Some (partially incorrect and also incomplete) protocol docs are available from the vendor.
The interface parameters for the UNI-T UT-D02 serial cable are 9600/8n1.
A packet consists of 23 bytes:
Byte(s) | Name | Description |
---|---|---|
0 | Function code | Bytes 0 and 1 determine the measurement mode. |
1 | Function select code | Bytes 0 and 1 determine the measurement mode. |
2 | Range | |
3-7 | 5 main display digits | |
8-12 | 5 auxiliary display digits | |
13 | ? | |
14 | ? | |
15 | Status | |
16 | Option 1 | |
17 | Option 2 | |
18 | Option 3 | |
19 | Option 4 | |
20 | Dual display | |
21 | Line feed | Always 10 / 0x0a. |
22 | Carriage return | Always 13 / 0x0d. |
Measurement modes:
Function code | Function select code | Measurement mode |
---|---|---|
0x30 | 0x30 | DCV |
0x30 | 0x31 | ACV |
0x31 | 0x30 | DCmV |
0x31 | 0x31 | Temperature (Celsius and Fahrenheit) |
0x32 | 0x30 | Resistance |
0x32 | 0x31 | Continuity |
0x33 | 0x30 | Capacitance |
0x34 | 0x30 | Diode |
0x35 | 0x30 | Frequency |
0x35 | 0x31 | Loop current, (4-20mA)% |
0x36 | 0x30 | DCuA |
0x36 | 0x31 | ACuA |
0x37 | 0x30 | DCmA |
0x37 | 0x31 | ACmA |
0x38 | 0x30 | DCA |
0x38 | 0x31 | ACA |
0x39 | 0x30 | Active/real power + apparent power |
0x39 | 0x31 | Power factor + frequency |
0x39 | 0x32 | Voltage effective value + current effective value |
Notes:
- The bargraph value (only shown on the LCD for voltage, current, and resistance mode) is not contained in the protocol.
- The auto-poweroff feature which powers the device off after 15 minutes is always disabled when the PC interface is "active" (i.e. the user pressed the REL/PC button for 1 second). Thus the respective "auto-poweroff" bit/flag, which is contained in the protocol, always has the same value.
- The backlight status (on/off) is contained in the protocol.