Voltcraft ME-42
 | |
| Status | in progress |
|---|---|
| Source code | serial-dmm |
| Counts | 4000 |
| IEC 61010-1 | CAT II (750 V AC/1000 V DC) |
| Connectivity | RS-232 (DB9) |
| Measurements | voltage, current, resistance, diode, continuity |
| Features | autorange, hold, bargraph |
| Website | conrad.de |
The Voltcraft ME-42 is a 4000 counts, CAT II (750/1000V) handheld digital multimeter with RS232 connectivity. It is an OEM version of the Metex ME-42. The device was sold by Conrad Elektronik as article 120130 starting from 1999 and is not available any more.
Hardware
Multimeter:
- TODO
- Fuses: 800mA/250V 5x20mm and 15A/250V 6x30mm (superfast, ceramic fuses)
- Battery: 9V NEDA 1604 or 6F22
RS232 cable:
Standard RS-232 cable with DB9 (M) plug.
During tests run by Matthias, this device did not work with several USB to serial converters (tested MosChip, Prolific, FTDI chipsets), only on a real "RS-232" port.
One source on the net [1] reported a very low battery life.
Photos
Multimeter:
Front
Back
Inside, with shielding
Back of board, without shielding
Board and power button removed
RS-232 interface and cover
Protocol
See Multimeter_ICs#Metex_14-byte_ASCII for the DMM IC protocol.
Model family
It seems that this device belongs to a family of several similiar devices and OEM models.
| Metex | Conrad | PeakTech | Radio Shack | RMS | Frequency | Transistor | Logic | Temp | Cap. | Remarks |
|---|---|---|---|---|---|---|---|---|---|---|
| Metex ME-11 | - | ? | RadioShack 22-805 | ? | ? | ? | ? | ? | ? | Amps manual range; seems to be similiar to ME-42
|
| Metex ME-21 | - | ? | ? | - | ● | - | ● | - | ? | Manual Range |
| Metex ME-22 | Voltcraft ME-22 | ? | ? | ? | ● | ● | ● | ● | ? | Manual Range |
| Metex ME-22 RMS | Voltcraft ME-22 RMS | ? | ? | ● | ● | ● | ● | ● | ? | Manual Range |
| Metex ME-31 | - | PeakTech 3410 | ? | ? | ? | ● | ? | ● | ? | |
| Metex ME-32 | Voltcraft ME-32 | ? | ? | - | - | ● | - | ● | ● | Amps manual range |
| Metex ME-42 | Voltcraft ME-42 | ? | ? | - | - | - | - | - | - | Amps manual range |
Resources
Measurement functions and ranges
| Measurement function | Range | Resolution | Accuracy | sigrok result | Remarks |
|---|---|---|---|---|---|
| V= | 400.0 mV | 100 μV | ±(0.5% + 3) | mq V, unit V, mqflags DC | " |
| 4.000 V | 1 mV | " | |||
| 40.00 V | 10 mV | " | |||
| 400.0 V | 100 mV | " | |||
| 1000 V | 1 V | " | |||
| V≈ | 400.0 mV | 100 μV | ±(1.0% + 5) | mq V, unit V, mqflags AC | 40 Hz - 100 Hz |
| 4.000 V | 1 mV | " | 40 Hz - 400 Hz | ||
| 40.00 V | 10 mV | " | " | ||
| 400.0 V | 100 mV | " | " | ||
| 750 V | 1 V | " | " | ||
| A= | 4.000 mA | 1 µA | ±(0.8% + 3) | mq Curr., unit A, mqflags DC | |
| 400.0 mA | 100 µA | ±(1,2% + 3) | " | ||
| 20.00 A | 10 mA | ±(2,0% + 5) | " | ||
| A≈ | 4.000 mA | 10 µA | ±(1,0% + 5) | mq Curr., unit A, mqflags AC | |
| 300.0 mA | 100 µA | ±(1,5% + 5) | " | ||
| 20.00 A | 10 mA | ±(3.0% + 5) | " | ||
| Ω | 400.0 Ω | 100 mΩ | mq Res., unit Ω, mqflags - | Continuity beep < 50 Ω | |
| 4.000 kΩ | 1 Ω | " | |||
| 40.00 kΩ | 10 Ω | " | |||
| 400.0 kΩ | 100 Ω | " | |||
| 4.000 MΩ | 1 kΩ | " | |||
| 40.00 MΩ | 10 kΩ | " | |||
| Diode | 2.000 V– | 1 mV | mq V, unit V, mqflags DC,DIODE | Max. 1,5 mA | |
| Data Hold | - |
The column "sigrok result" contains in short form what the driver generates for the resp. data type.
The device seems to be extremely slow when the RS-232 interface is enabled and often takes up to about 10 seconds to detect a changed value or switch to another range. During this time a previous value keeps being sent. When changing to a new range automatically or manually, the device might send the old value scaled to the new range for a short time. This behaviour is caused by the device, not by sigrok!