Relay module with display for extension of GfG controllers

The relay module GMA200-RTD with color display extends a controller of the GMA200 series or the compactly designed GMA22 in a gas detection system by 16 individually programmable relays with one floating signal change-over contact each. This allows additional safety measures such as visual and audible alarms or ventilation systems to be operated via the controller. The relay module has LED indicators and the connection is done via the RS-485 interface. The GMA200-RTD is installed by top hat rail mounting (TS35) or in a control cabinet.

GfG controllers and certain transmitters have internal relays. External alarm devices such as information signs, warning lights and signal horns can thus be directly connected and managed. The same applies to measurement-controlled ventilation systems and valves. Complex gas warning systems, however, require a large number of automatic safety measures that are initiated when the defined gas limit values are exceeded or undershot. Up to four relay modules GMA200-RTD can be connected to the GfG controllers via the RS-485 interface. The total number of relays per gas detection computer can thus be increased by up to 64.

Extension of safety functions
The GMA200-RTD is equipped with 16 relays, each with a floating signal changeover contact. In addition to 16 external alarm devices or other measurement-controlled devices and functions, an external pushbutton can also be connected for alarm acknowledgement. Due to the spatial separation of controller and relay module, safety measures in remote areas (up to 1,200 m) can be implemented with significantly less cabling effort. The operating voltage of the GMA200-RTD is 24 V DC. Power supply is also possible redundantly via two power supplies. The device is configured via a gas measuring computer (by GMA200Config software) or via the mini-USB socket (USB type B) by PC.

Displays and Functional Safety
The GMA200-RTD displays the measured values of the transmitters connected via the controller as individual or collective displays. In the event of an alarm, the background color of the 2.2-inch color display changes to red. The relay module is operated via a pushbutton interface next to the display. Each relay is indicated by an LED on the front of the relay module, which will change color to show its operation and any alarms or faults. In addition, four status LEDs indicate the operating status as well as service and error messages. The hardware of the GMA200-RTD meets the requirements of functional safety according to DIN EN 50402. In single-channel use (1oo1), the SIL capability corresponds to 2, in redundant use (1oo2) to 3.


Key features at a glance:

General information:

  • Suitable for the GMA200 and GMA22 gas detection computers
  • 16 relays, each with one potential-free changeover contact with status display
  • 2.2 inch color display and pushbutton interface
  • Connection via RS-485 interface (Modbus)
  • Up to 4 relay modules per controller
  • Top-hat rail mounting (TS35)
  • Configuration via software GMA200Config with gas measuring computer and PC

Approvals / Certifications:

  • SIL level 2/3 (depending on contact load of relay switching output)


Extensions and accessories



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

Accessories GMA200-RT

Accessories GMA200-RT

Complete list of accessories for the GMA200-RT
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