Gossen Metrawatt

Gossen Metrawatt is a German manufacturer of professional and high-end test and measurement equipment, including multimeters.

This article tries to give an overview of the multimeters with interfaces for data exchange, OEM models and communication.

Company

• http://www.gossenmetrawatt.com/ (Homepage)
• https://de.wikipedia.org/wiki/Gossen_Metrawatt

Multimeters

One remark concerning device names: The manufacturer writes the name of the device series sometimes "METRAHit", sometimes METRAHIT or even METRA HIT, sometimes not even consistently for the same device. For simplicity it will be "Metrahit" here most of the time, other names alike.

Metrahit 1x series

Gossen Metrawatt	Siemens OEM	Rishabh	HT OEM	Count	TRMS	Supported	Remarks
Metrahit 12S (GTM 2012 000 R0003)		Rishmulti 12S		3100	-	○
Metrahit 13S (GTM 2013 000 R0003)		Rishmulti 13S		3100	-	○
Metrahit 14A (GTM 2014 000 R0007)	B1102 7KB1102-8AA			3100	-	●
Metrahit 14S (GTM 2014 000 R0003)	B1103 7KB1103-8AA	Rishmulti 14S		3100	-	●	Tested successfully by a sigrok user.
Metrahit ONE PLUS (M204D) [1]				3100	-	●	Seems to be the successor of the 14S, detected as 14S. Tested successfully by a sigrok user.
Metrahit 15S (GTM 2015 000 R0003)		Rishmulti 15S	HT Instruments HT410	3100	-	●
Metrahit 16S (GTM 2016 000 R0003)	B1104 7KB1104-8AA	Rishmulti 16S		3100	●	○
Metrahit 16I (M216B)				3100	●	●	Multimeter and insulation tester 500/1000 V
Metrahit 16L (M216L)				3100	●	○	Seems to be a Metrahit 16I with additional duty cycle function
Metrahit 16T (M216A)				3100	●	○	Multimeter and insulation tester 100 V telecom; seems to be almost identical to T-Com KMM2002.
T-Com KMM2002 (M216T)				3100	●	●	Multimeter and insulation tester 100 V telecom
Metrahit 16U (M216U)				3100	●	○	Multimeter and insulation tester for symmetrical copper wire, very similar to 16T
Metrahit 18C						-	Calibrator; This device is a signal generator, not a multimeter, and seems to have not much in common with the multimeters except the case. Added here just for completeness.
Metrahit 18S (GTM 2018 000 R0003)	B1108 7KB1108-8AA	Rishmulti 18S		31000	●	●

These multimeter can send data unidirectionally via IR/RS232 (Send Mode). It seems that the 3100 count types are actually 31000 count types that do not display the last digit, but can deliver it via the serial interface.

Currently the Metrahit 14A, 14S, ONE Plus, 15S (HT410), 16I, KMM2002 and 18S are supported by sigrok using the driver gmc-mh-1x-2x-rs232.

The models marked with ○ in the Supported row are untested, but expected to work. See section Metrahit 1x/2x Send Mode for details.

Please contact Matthias if you have one of the unsupported devices and can test it.

The devices are not available from Gossen Metrawatt any more, but it seems that a company in India named Rishabh makes slightly redesigned versions of some models. The HT Instruments HT410 seems to be another OEM model, probably made by Rishabh.

The Metrahit 1x series includes some more devices (Metrahit 15 and 16 without letter, Milliohm Meter Metrahit 17, some sold as ancestor brand ABB Metrawatt) that are unsupported because they do not have an IR interface.

Metrahit 2x Series

Gossen Metrawatt	Siemens OEM	LEM ELMES/ HEME/NORMA OEM	Dranetz brand	Count	TRMS	Supported gmc-mh-1x-2x-rs232	Supported gmc-mh-2x-bd232	Remarks
Metrahit 22S (M222A)		Unigor 330		31000		○	○	Signal Generator; Current measurement only with clamp
Metrahit 22M (M222B)				31000		○	○	Signal Generator; Like 22S + Integrated measurement data storage
Metrahit 23S (M223A)				31000		○	○	Signal Generator; special 16A (unfused) range for use with measuring current transformers
Metrahit 24S (M224A)				31000		○	○	Signal Generator
Metrahit 25S (M225A)	B1102 7KB1102-8BA	Unigor 355		31000	AC	●	●	Signal Generator
Metrahit 26S (M226A)				31000	●	○	○	Signal Generator
Metrahit 26M (M226B)					●	○	○	Signal Generator; Like 26S + Integrated measurement data storage
Metrahit 27EX (M227F)						-	-	Milliohm meter for explosive atmospheres
Metrahit 27EX Airbus (M227G)						-	-	Milliohm meter for explosive atmospheres, special version approved by Airbus.
Metrahit 27I (M227B)	B1107 B 7KB1107-8BA ?		DranTech PMIT		●	-	-	Milliohm and Megaohm, insulation tester. ASCII-based communication protocol similiar to SCPI. Same device available as part of avionic kit 27AS (M227C).
Metrahit H+E Car (M227T)					●	-	-	Special tester for Electro and Hybrid Cars. Milliohm and Megaohm, insulation tester. Seems to be a Metrahit 27I in different colors
Metrahit 27M (M227A)					●	-	-	Multimeter and Milliohmmeter
Metrahit 28C (M231A)				310000	●	-	-	Multimeter, Milliohmmeter + Calibrator
Metrahit 28C light (M232A)				(30000)	-	-	-	Calibrator; Only a signal generator, not a multimeter, added here just for completeness.
Metrahit 28S (M228A)	B1105 7KB1105-8AA	Unigor 380		310000	●	●	●
Metrahit 29S (M229A)	B1106 7KB1106-8AA	Unigor 390	PowerLogger 10	310000	●	●	(○)	Energy and power disturbance measurement functions, integrated memory. Energy measurement functions not implemented yet for driver gmc-mh-2x-bd232.
Metrahit 30M (M230B)			DranTech ULTRA	1200000	●	-	-	Laboratory multimeter; special communication protocol not compatible with other Metrahit 1x/2x devices!

The Metrahit 2x series supports unidirectional (Send Mode) and bidirectional data exchange via IR.

Currently the Metrahit 25S and 28S (Siemens B1105) are supported by two different drivers:

• gmc-mh-1x-2x-rs232: Send Mode
• gmc-mh-2x-bd232: Bidirectional Mode

The models marked with ○ in a Supported row are untested, but expected to work. Please contact Matthias if you have one of these unsupported devices and can test it.

See Communication Protocols for more details.

Metrahit Starline Series

The series of newer devices with only three sockets (only one socket for all current measurement ranges) is called Starline Series. The manufacturer sub-divides this further into an A Series, E Series and S Series, which does not make a big difference concerning communicating with the devices.

Gossen Metrawatt	Siemens OEM	Dranetz brand	Count	Supported	Remarks
Metrahit X-Tra (M240A)	Siemens B1125 7KB1125-8AA	Drantech XTRA	12000	-	Teardown on EEVblog: 1
Metrahit Outdoor (M240o)		DranTech Outdoor	12000	-	IP65; seems to be a more rugged, different-coloured flavour of the X-Tra
Seculife Hit (M687A)			12000	-	Seems to be a white, "medical" version of the X-Tra
Metrahit EBase (M251A)			60000	-
Metrahit ESpecial (M252A)			60000	-
Metrahit ETech (M253A)			60000	-	Simular to Extra, but fewer functions.
Metrahit Extra (M250A)			60000	-
Metrahit Energy (M249A)			60000	-	Energy and power analysis functions; EEVblog: Teardown: 1 Battery measurement: 2
Metrahit Ultra (M248A)			310000	-	Precision Multimeter
Metrahit Ultra BT (M248B)			310000	-	Precision Multimeter with additional Bluetooth interface
Metrahit Iso (M246B)		DranTech ISO	30000	-	Multimeter with insulation measurement 50/100/250/500/1000 V, 3,1 GΩ
Metrahit Iso Aero (M246M)			30000	-	Multimeter with insulation measurement 10/50/100/250/500/1000 V, 3,1 GΩ
Metrahit T-Com (M246A)			3100	-	Multimeter with special functions for symmetrical copper wiring, insulation measurement 100V
Metrahit T-Com Plus (M246S)			3100	-	Like T-Com, some more functions.
Metrahit Coil (M246C)			31000	-	Special functions for measuring electric drives and insulation measurement
Metracal MC (M245A)			60000	-	Multimeter and calibrator; older versions named Metrahit Multical.

Metraport Series

Gossen Metrawatt	Volkswagen OEM	Count	Remarks
Metraport 40S (M234D)	V.A.G 1526E	30000	Foldable multimeter; USB interface, resettable fuse

Communication Hardware

Most Gossen Metrawatt multimeters having data communication support communicate unidirectionally or bi-directionally through the case using IR and proprietary communication adaptors. The advantage of this construction is that it allows a closed case without unnecessary holes. One model, the Metrahit Outdoor, even has IP65 protection! The disadvantage is a need for special, expensive adaptors to convert this to common RS232 or USB.

The IR signal is just serial data encoded as SIR (Asynchronous Serial Infrared; signal inverted, bits only about 3/16 of the ordinary length). While SIR is the physical layer of IrDA for lower baud rates, an IrDA communication adaptor will not work because it implements further protocols on top. Some details (optical specification; 8192 baud and 6 bit modes required by some multimeters) seem not to conform to the SIR specs.

The Metrahit Ultra BT also supports Bluetooth. The Metraport 40S communicates via integrated USB only.

Metrahit 1x/2x series

Metrahit RS232

IR→RS232 adaptor for unidirectional communication from the multimeter to the computer.

Works with Metrahit 1x and with Metrahit 2x devices in Send Mode.

RS232 parameters: 8192 (Metrahit 1x)/9600 Baud (Metrahit 2x), 6N1, DTR ON, RTS ON.

The communication speed of 8192 Baud and 6 data bits might not be supported by some operating systems and many RS232-USB adaptors.

Not available any more.

• 

  RS232 IR→RS232 adaptor

• 

  With counterpart Metrahit 18S

• 

  Attached to Metrahit 18S

The adaptor contains just discrete components and ICs, no microcontroller.

Metrahit SI232

IR→RS232 adaptor for unidirectional communication from the multimeter to the computer and data storage.

Works with Metrahit 1x and with Metrahit 2x devices in Send Mode.

Up to six SI232 can be cascaded to communicate to the computer via a single RS232 interface. Up to 10 SI232 can be cascaded to measure offline synchronously.

128 kByte battery-buffered CMOS memory, up to about 100000 data sets.

Multimeter: 8192 Baud, 950 nm, 6N1.
RS232: 9600/19200/38400 Baud, 8N1.

Not available from Gossen Metrawatt any more. It seems that Rishab in India 1 still sells it as OEM product Rish SI232.

Metrahit BD232

IR↔RS232 adaptor allowing bidirectional communication between multimeter and computer.

Works with Metrahit 1x and 2x devices and the 30M.

With Metrahit 2x/30M devices up to six BD232 can be cascaded to communicate to the computer via a single RS232 interface. When only Metrahit 2x multimeters are used, BD232 and SI232 adaptors can be mixed.

9600 Baud.

• 

  Left side

• 

  Right side

• 

  Inside

• 

  Board bottom

• 

  Board top

The adaptor contains just discrete components and ICs, no microcontroller.

Metrahit SI232-II

IR↔RS232 adaptor allowing bidirectional communication between multimeter and computer and data storage.

Works with Metrahit 1x and Metrahit 2x devices.

128 kByte battery-buffered CMOS memory, up to about 100000 data sets.

Multimeter: 8192/9600 Baud, 950 nm, 8N1.
RS232: 9600/19200/38400 Baud, 8N1.

4-8 SI232-II (depending on multimeter types and baud rate) can be cascaded to communicate to the computer via a single RS232 interface. Up to 10 SI232-II can be cascaded to measure offline synchronously.

Not available any more.

• 

  LEM Unigor mem 232 II (OEM version of SI232-II)

• 

  Inside

USB-Hit

IR↔USB adaptor for Metrahit.

For Metrahit 2x/30M devices only.

Metrahit Starline Series

USB X-Tra

IR↔USB adaptor for the Starline Series devices.

A USB to SIR converter like this nice Open Souce hardware design by 0xdeadbeef/V. Ott will work as a cheaper replacement.

Bluetooth

Bluetooth 2.1 + EDR, Class 2

For the Metrahit Ultra BT.

Metraport Series

USB

The Metraport 40S has got an integrated USB 1.1 interface with USB Mini-B receptacle.

Communication Protocols

While the older devices MetraHit 1x-30M use proprietary protocols, the newer devices of the socalled Starline Series use a protocol close to SCPI. Descriptions of the communication protocols are available from the manufacturer.

Metrahit 1x/2x Send Mode

Proprietary binary protocol. Used for sending data from multimeter to PC.

This mode is supported by the driver gmc-mh-1x-2x-rs232 using the interface RS232.

Supported devices: Metrahit 14A, 15S (HT410), 16I, KMM2002, 18S, 25S, 28S (Siemens B1105), 29S.

Other devices of the Metrahit 1x/2x series except the 18C/27x/28Cx devices should work, too, but are untested.

Metrahit 2x Bidirectional Mode

Proprietary binary protocols. Used for bidirectional communication between computer and most Metrahit 2x multimeters.

There seem to be several "sub-modes". See description available from manufacturer on request.

This mode is supported (incompletely) by the driver gmc-mh-2x-bd232 using one of the interfaces BD232 or SI232-II. The interface USB-Hit might work, too, but is untested.

The driver will try to power on BD232 and SI232-II interfaces and connected multimeters before scanning for devices. The driver can power off a multimeter using the command SR_CONF_POWER_OFF with a boolean parameter of TRUE.

Supported devices: Metrahit 25S and Siemens B1105 (Metrahit 28S). Other multimeters of the series should work, too, but are untested.

Currently the following restrictions apply:

• Only one multimeter per RS-232 interface supported. Several multimeters on cascaded BD232 or SI232-II interfaces might be detected, but only one at a time can be used.
• Measured values are read one by one by polling. Depending on the sample rate, this could theoretically cause loss of some values.
• Reading of data stored in memory of storage adaptor SI232-II or multimeter (Metrahit 22M, 26M, 29S) not implemented yet.
• Setting of multimeter configuration not supported yet.

Metrahit 30M

The protocol is proprietary and seems to be quite different from the Metrahit 1x/2x series although communication can use some of the same IR↔Serial adaptors (at least BD232, USB-Hit).

Metrahit 27I, 27M, 28C, Starline Series, Metraport 40S

Newer Metrahit devices use a proprietary communication protocol that is (mostly) ASCII and oriented at SCPI. A driver is under development.

Depending on the device type, an interface BD232 or USB-Hit for Metrahit 27x or 28C, USB X-Tra for supported devices of the Starline Series or an USB cable with a type Mini-B plug for the Metraport 40S is required.

LabView

Gossen Metrawatt offers LabView drivers for the Metrahit Energy, the Metrahit Ultra and the Metraport 40S.

See also

• BBC Goertz Metrawatt M2110