Professional digital instrument with support for two sensors

Industrial Refrigerant Gas Detector
  • Flexible two-sensor capability, local and/or remote
  • One user-interface platform for all sensor types
  • Two analog outputs and Modbus RTU interface
  • Three fully configurable, user-assignable relays
  • Magnetic wand enables easy, non-intrusive configuration/calibration
  • IP66 ABS or aluminum enclosure options

Bacharach’s advanced MGS-550 gas detector can utilize any combination of sensor technologies, including electrochemical, semiconductor (MOS), catalytic bead or infrared, in a single platform for unparalleled detection capability. The MGS-550 can easily be connected to any central control system using the current and volt analog output or the Modbus RTU interface. With three user assignable relays, it can also function as a stand-alone unit without the need to wire alarm devices back to a central system.

The straightforward menu structure is identical throughout the platform reducing the amount of training required for installing and maintaining this product family. At any point in time, the instrument can be upgraded from a one sensor to a two sensor system by simply registering another sensor. The MGS-550 is furnished with two analog outputs which can be assigned as redundant for one or for transmit the signal of two sensors.



Type Gas detector using Semiconductor, Electrochemical, Infrared or Catalytic Bead sensor.
For one or two sensor configuration
Gases Toxic gases: Ammonia, Carbon Dioxide, Carbon Monoxide, Ethylene, Nitrogen Dioxide and Ozone
Combustible gases: Methane, Propane, Butane and LPG
Refrigerants: Ammonia, Carbon Dioxide, Hydrocarbons, and HFCs, HCFCs, CFCs
Measuring Range
O2 30 Vol%
CO 1,000 ppm
NH2*, *** 100 / 1,000 / 5,000 / 10,000 ppm / 100 %LEL
CO2 5,000 / 10,000 / 20,000 / 30,000 / 40,000 / 50,000 ppm
Refrigerants 1,000 / 10,000 ppm
Combustible Gases 100% LEL
C2H4 2,000 ppm
NO2 20 ppm
Display 5-digit, 7-segment red LED and green status LEDs
Audible Alarm 85 dB buzzer
Output Analog 4 to 20 mA, 0 to 5 V, 0 to 10 V, 1 to 5 V, 2 to 10 V
Digital Modbus RTU via RS 485
Power Supply 19.5 to 28.5 VDC or 24 VAC ± 20%; 3- or 4-wire
Relay 3 relays, SPDT, user assignable
Rating 1 A @ 24 VDC, 0.25 A @ 240 VAC, resistive load
Alarm delay 0 to 15 minutes; user-programmable
Ambient Conditions Temperature - 40 to +120 °F (40 to +50 °C)
Humidity 5 to 90 %RH, non condensing
Altitude 0 to 10,000 ft (3,050 m)
Enclosure options General Purpose: IP66 Rated ABS with four M20 x 1.5 ports
Rugged, Explosion-Proof Certified****: Powder coated, copper free aluminum, with four M20 x 1.5 ports
Size (w x h x d) General Purpose: 8.3” x 8.9” x 3.4” (210 x 225 x 85 mm)
Rugged, Explosion-Proof Certified****: 4.9” x 7.5” x 3.5” (125 x 190 x 90 mm)
Weight General Purpose: 2 lbs (1 kg)

Explosion-proof:  3.5 lbs (1.6 kg)

Approvals CE, UL, CSA, IEC, EN 61010-1

*Ammonia available as low temperature version -40°F / -40°C (not for 5,000 ppm electrochemical sensor)

**Not IP66 rated; not available for XP enclosure

***Not available for XP enclosure

**** MGS-550 is not approved as an explosion-proof product and should NOT be installed in hazardous locations