Gossen Metrawatt Metrahit 25S

Gossen Metrawatt Metrahit 25S

Status	supported
Source code	gmc_mh_1x_2x
Counts	31000
IEC 61010-1	CAT III 1000 V, CAT IV 600 V
Connectivity	Infrared (RS232)
Measurements	voltage, current, resistance, capacitance, temperature, diode, continuity
Features	autorange, data hold
Website	[1]

The Gossen Metrawatt Metrahit 25S is a 4.5 digit, 31000 counts 1000V CAT III/600 V CAT IV handheld digital multimeter with IR (RS232) connectivity.

Hardware

• Power supply:
  • Battery: 2x 1,5 V IEC R 6, IEC LR 6 or corresponding NiCd rechargeable batteries
• Fuse:
  • Current 300 mA: FF (UR) 1,6 A/1000 V AC/DC (10 kA) 6,3 mm x 32 mm
  • Current 3A/10A: FF (UR) 10 A/1000 V AC/DC (30 kA) 10 mm x 38 mm

Using the device with sigrok

The device is supported in Send Mode using a RS232 interface by the driver gmc-mh-1x-2x-rs232 (actually this should work, but with Matthias' test device it did not, so it's untested). Set the multimeter to use the communication adaptor RS232.

The multimeter is also supported in bidirectional mode using a BD232 or SI232-II interface by the driver gmc-mh-2x-bd232. Set the multimeter to use the communication adaptor BD232.

The device might be not detected by the driver if it is in a mode where it sends data rarely, either with a huge send interval or with a measurement function that delivers a very low data rate, e.g. temperature measurements with K type sensor. Then it should be set to a mode with higher data rate during the initialisation of the driver.

Measurement functions and ranges

Measurement function	Range	Resolution	Accuracy	sigrok result	Remarks
V=	300 mV	10 μV	±(0,05% 3)	mq V, unit V, mqflags DC
	3 V	100 μV		"
	30 V	1 mV		"
	300 V	10 mV		"
	1000 V	100 mV		"
V≈	300 mV	100 µV	±(0,5% + 30) (> 500 Digit))	mq V, unit V, mqflags AC,RMS
	3 V	100 μV	±(0,2% + 30)	"
	30 V	1 mV		"
	300 V	10 mV		"
	1000 V	100 mV		"
V db≈	-48 - 63 dB	0,01 dB	± 0,1 dB	mq V, unit V, mqflags AC,RMS	Actually the 5 AC ranges, see there for accuracy.
A=	300.00 µA	10 nA	0,1% + 5	mq Curr., unit A, mqflags DC
	3.0000 mA	100 nA		"
	30.000 mA	1 mA	0,05% + 5	"
	300.00 mA	10 µA	0,5% + 5	"
	3.0000 A	100 µA	0,5% + 10	"
	10.000 A	1 mA		"
A≃	300.00 µA	10 nA	0,5% + 30	mq Curr., unit A, mqflags AC,DC,RMS
	3.0000 mA	100 nA		"
	30.000 mA	1 µA		"
	300.00 mA	10 µA		"
	3.0000 A	100 µA	0,75% + 30	"
	10.000 A	1 mA		"
Ω	300.00 Ω	10 mΩ	0,1% + 5	mq Res., unit Ω, mqflags -
	3.0000 kΩ	100 mΩ		"
	30.000 kΩ	1 Ω		"
	300.00 kΩ	10 Ω		"
	3.0000 MΩ	100 Ω		"
	30.000 MΩ	1k Ω	2% + 5	"
Ohm/Cont.	300 Ω	100 mΩ	1% + 3%	mq Res., unit Ω, mqflags -
Diode	3 V	1 mV	0.2% + 3	mq V, unit V, mqflags DC,DIODE
Cap. F	3.000 nF	1 pF	1.0% + 5	mq Cap., unit F, mqflags -
	30.00 nF	10 pF		"
	300.0 nF	100 pF		"
	3.000 µF	1 nF		"
	30.00 µF	10 nF		"
	300.0 µF	100 nF	±(5.0% + 6)	"
	3.000 mF	1 µF		"
	30.00 mF	1 µF	±(5.0% + 30)	"
Hz≈, ≃	300.00 Hz	0.01 Hz	±(0.1% + 1)	mq Freq., unit Hz, mqflags AC,DC	To activate in AC, press yellow button twice.
	3.0000 kHz	0.1 Hz		"
	100.000 kHz	10 Hz		"
°C	Pt100/Pt1000 –200.0 - -100.0 °C	0.1 °C	1 K	mq Temp., unit °C, mqflags -
	Pt100/Pt1000 -100.0 - +100.0 °C		0,8 K	"
	Pt100/Pt1000 +100.0 - +850.0 °C		±(0,5% + 3)	"
°F	"	"	"	mq Temp., unit °C (!), mqflags -	Details and ranges like °C. The protocol does not allow to distinguish between °C and °F, so the unit is always °C.
Event count				mq V, unit V, mqflags AC,RMS,REL	To activate, switch to voltage AC, press yellow button twice. Press up to 4 times to cycle parameters, press long to stop. See manual. Not useful remotely because the voltage measurement value is sent, not the counter.
Stop Watch		100 ns		(Time data)	Max. 100 Min. Press AUTO for start/stop, DATA for reset. Not useful remotely because the stop watch delivers only zeros.
Data Hold				mqflags += HOLD	Disabled while IR interface is active on  Matthias' test device.
MIN				mqflags += MIN	Influences only display, via IR flag is set, but actual current value is delivered.
MAX				mqflags += MAX	Influences only display, via IR flag is set, but actual current value is delivered.

The Accuracy row was simplified, see manual for exact specs. If the value contains three values, the middle value is % or range.

The column "sigrok result" contains in short form what the driver generates for the resp. data type.