Versatile controller for smaller gas detection systems

Gases are also used, or may be found, in smaller facilities such as combined heat and power plants and cold stores. A reliable gas detection system therefore makes a significant contribution to the safety of people, equipment and the environment. We have developed the GMA22-MW for gas measurement in such applications. Up to four transmitters and relay modules can be connected to the controller. Also part of the extensive features is a display for measured value indication, integrated visual and audible alarms, and four internal relays for additional safety measures.

In many processes, gases need to be controlled - regardless of the size of the plant. Even in smaller applications, a gas warning system is indispensable. The GMA22-MW is the ideal controller for this purpose, if

  • up to four transmitters are used
  • toxic and combustible gases or oxygen are to be monitored
  • a central measured value display is required outside hazardous areas
  • internal or external relays are required for safety measures
  • acoustic and visual alarms are to be initiated in the event of danger from gases

Wide range of connection options
Up to four transmitters can be connected to the GMA22-MW using the RS-485 interface. In addition to the measured values, the controller also receives digital information such as status messages and service information. Alternatively, it is also possible to connect a transmitter from an analog 4-20 mA or 0.2-1 mA input.
If this is an ACDC capable transmitter from GfG, digital information can also be transmitted using the analog lines (only 4-20 mA). Many transmitters from GfG can be calibrated remotely when digitally integrated or ACDC. This greatly simplifies service which can be performed by a single technician.

Exterior features
The dimensions (97 x 140 x 50 mm) are exceptionally small. This allows the GMA22-MW to be mounted almost anywhere on the wall. The housing is protected against dust and splash water (IP64).  This enables use under difficult external conditions.

The 2.2-inch display is backlit in color. It lights up green in normal operation and red in the event of an alarm. The alarm levels are signaled by two red LEDs. In addition, there is an acoustic alarm from the integrated horn.
Two further LEDs indicate operating and special states in green and yellow. Below the display there is a pushbutton interface for intuitive operation and alarm acknowledgement.

Internal and external relays
The GMA22-MW has four integrated relays for implementing safety measures. Additionally, up to four relay modules GMA200-RT can be connected using the RS-485 interface. With 16 potential-free change-over contacts each, the number of relays is increased up to 64.
Configuration of the GMA22-MW and the relay modules is completed using the GMA200Config software. Alarms, faults and measured values can be recorded in the data logger on a microSD card, if desired.

Key features at a glance:

General information:

  • Suitable for any GfG transmitter
  • Monitors 1 to 4 measuring points


  • 4 integrated relays for safety concepts
  • 4-20 mA (ACDC capable) or RS-485 (Modbus)
  • Color backlit 2.2 inch display
  • Four colored status LEDs
  • Visual and audible alarm
  • Compact housing for wall mounting (IP64)


  • Data logger (microSD card)
  • Different relay versions
  • Relay module for extension


Extensions and accessories



Relay module for extension of the GMA200 series and the GMA22
» more



Relay module with display for extension of GfG controllers
» more



Relay module for wall mounting to expand the GfG controllers
» more

Accessoires GMA22

Accessories GMA22

Here you'll find the complete list of accessories for the GMA22
» download PDF

Our experts are happy to answer your questions! How to find us