RKI M2A-XL Explosion-Proof Gas Transmitter

Name: RKI M2A-XL Explosion-Proof Gas Transmitter – Brochure & Quote
Brand: RKI
SKU: M2A-XL

An explosion-proof gas transmitter that works alone or with a controller

The RKI M2A-XL is a stand-alone fixed gas transmitter in a NEMA 4X cast-aluminium explosion-proof junction box. It can operate as an independent monitor or as part of an integrated system: it outputs 4-20 mA and Modbus RTU and has two programmable alarm relays and a fail relay, so it connects to virtually any controller, PLC or DCS, and works directly with the Beacon 110, 200, 410A, 800 and 3200 controllers. An OLED display behind the cover window shows the reading, and calibration is done with a magnetic wand so the housing never needs opening and the area does not have to be declassified for routine maintenance.

Technical specifications

Parameter	Specification
Sensor types	Catalytic LEL, infrared LEL / HC / CH4 / CO2, galvanic oxygen, electrochemical CO, H2S and toxic cells; MPS LEL detector also covered in the manual
Combustible and CO2 ranges	Catalytic 0-100% LEL or 0-9000 ppm CH4; IR CH4 0-100% LEL, 0-5% vol, 0-100% vol; IR CO2 0-5000 ppm, 0-5%, 0-50%, 0-100% vol
Other ranges	O2 0-25.0% vol; CO 0-300 ppm (also 0-100 and 0-200 ppm); H2S 0-100 ppm (also 0-50 ppm)
Toxic ranges (examples)	NH3 0-75 to 0-500 ppm; Cl2 0-3 / 0-5 / 0-10 ppm; ClO2 0-1 / 0-3 / 0-5 ppm; HCN 0-15 ppm; NO2 0-15 ppm; SO2 0-6 / 0-10 ppm; AsH3 0-1.5 ppm; PH3 0-1.0 ppm; HCl 0-20 ppm; NO 0-100 ppm
Response time T90	Catalytic LEL 35 s or less; IR 30 s or less; O2 and CO 90 s or less; H2S 60 s or less; toxic cells per brochure table
Outputs	Linear 4-20 mA; Modbus RTU RS-485 as standard; relays 5 A Form C for Alarm 1, Alarm 2 and Fail
Alarms	Two programmable setpoints, rising or falling, latching or self-resetting, on and off delays, normally energized or de-energized; LEDs Alarm 1 amber, Alarm 2 red, Fail red
Supply	10 to 30 VDC; maximum draw 160 mA (catalytic and IR) or 125 mA (O2, CO, H2S) with both alarms and all relays active at 24 VDC
Display	Alphanumeric OLED, 2 lines of 8 characters
Enclosure	Cast aluminium, epoxy powder coated, o-ring sealed, NEMA 4X, explosion proof for Class I, Div. 1, Groups B, C, D; non-explosion-proof toxic sensors designed for Class I, Div. 2
Dimensions	6.2 in H (158 mm, excluding sensor) x 5.66 in W (144 mm) x 4.86 in D (124 mm)
Operating temperature	Catalytic LEL -40 to 75 C; IR -40 to 50 C; O2 and CO -20 to 50 C; H2S -40 to 50 C; toxic cells vary (brochure)
Humidity and location	5 to 95% RH non-condensing; indoor or outdoor; patented water-repellent sensor coating
Wiring distance to controller	3-wire: 2,500 ft (18 AWG), 5,000 ft (16 AWG), 8,000 ft (14 AWG)
Warranty	One year, materials and workmanship

Choosing the sensor and part number

The M2A-XL part number is built from the gas. In the brochure the UL-version transmitters include 65-2640XL (catalytic LEL), 65-2647XL (catalytic 0-9000 ppm CH4), 65-2641XL (hydrogen-specific LEL), 65-2643XL-05 (oxygen), 65-2645XL-05 (H2S 0-100 ppm), 65-2646XL-05 (CO 0-300 ppm), 65-2649XL-CH4 and -HC and 65-2658XL-CH4 (infrared), and 65-2660XL-02, -03, -05 and -10 (infrared CO2 in four ranges). CSA versions carry a -05 suffix. Toxic transmitters use the 65-2670XL series, for example 65-2670XL-NH3-75 for ammonia 0-75 ppm and 65-2670XL-CL2-5 for chlorine 0-5 ppm.

Pick catalytic sensors for general flammable gas, infrared where silicones, sulphur or oxygen-poor atmospheres would poison a catalytic bead, and the H2-specific head for hydrogen. Alarm defaults depend on the gas, for example 10% LEL and 50% LEL for combustibles, 19.5% falling and 23.5% rising for oxygen, and 10 ppm and 50 ppm for H2S 0-100 ppm. Accessories listed by RKI include remote-mount calibration adaptors, flow-through and aspirator adaptors, remote horns and lights, and calibration kits.

Documents and quotation

The attached file is the four-page RKI M2A-XL brochure; the Operator’s Manual (71-0610, Rev H) carries wiring, calibration and Modbus details. The controller family is covered on the page and under fire and gas detectors. Send the target gas, range, area classification and controller type for a quotation, and confirm the exact approval marking required for the site before ordering.

RKI gas detection range

The range covers portable monitors such as the GX-3R Pro, GX-Force and GX-6100, fixed-system detectors and controllers, wireless gas detection and calibration equipment. Typical uses are confined-space entry, refinery and petrochemical work, water and wastewater, and leak detection, with intrinsically safe approvals on the portable models.

Ordering RKI monitors

Tell us the gases and ranges, whether diffusion or sample-draw is needed, battery type and the approval marking required on site. We check the sensor configuration and calibration gas against the manufacturer datasheet before quoting. Pump-sampling units suit pre-entry checks of tanks and manholes, while compact diffusion monitors suit personal protection.

Frequently Asked Questions