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Transmitters

M2A

The RKI M2A™ is a state-of-the-art transmitter that can operate as an independent, stand-alone monitor or as part of an integrated system. The M2A connects with an analog or digital signal to virtually any controller, PLC, or DCS. Setup procedures are simplified with user friendly push buttons and OLED menus. It utilizes a magnetic wand technique for performing non-intrusive calibration. The M2A provides an automatic zero drift correction feature, which results in more stable readings and reduces the need for adjustments due to sensor aging.

The housing of the M2A does not need to be opened for zeroing or calibration, making it unnecessary to declassify the area for routine maintenance. It is designed so that a complete field calibration can be performed by one person. Sensor construction is rated Class I, Div. 1 Groups B, C, D for Flammables, CO, H2S, O2, and CO2, and Class I, Div. 2 for all other Toxics.

The transmitter provides a 4-20 mA output in addition to a Modbus digital output. It also has two levels of alarms with relays, plus a fail alarm with relay. A digital display of the gas concentration, as well as alarm and status lights, can be viewed through the front window.

The toxic sensors are electrochemical type plug-in sensors, which provide high specificity, fast response, and long life. The plug-in design allows quick replacement in the field with no tools required. Toxic sensors are designed for use in Class I, Div. 2 hazardous locations. Sensors available for NH3, SO2, PH3, AsH3, and HCN.

The M2A represents the latest leading edge technology in sensor / transmitters today.

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Features
Applications
Specification

Operates with or without a controller
Direct digital readout with OLED display
Available gases include : LEL, O2, H2S, CO, CO2, and 100% Vol CH4
Toxic gases include NH3, SO2, HCN, and more
Infrared sensor for Combustibles and CO2
4-20 mA & digital Modbus outputs standard
2 fully programmable alarm relays & fail relay

Non-intrusive calibration via magnetic wand
Explosion proof construction
Patented water repellent sensor cover
User friendly setup, push buttons & LCD menus
Long-life sensors (2 + years typical)

Petrochemical plants
Refineries
Water & wastewater treatment plants
Pulp & Paper mills

Manufacturing facilities
Automotive
Semiconductor plants
Chemical plants

	LEL General Purpose	LEL H₂ Specific	O₂ Oxygen	H₂S Hydrogen Sulfide	CO Carbon Monoxide	CH₄ Methane	HC Hydro-carbons	CO₂ Carbon Dioxide
Part#	65-2640RK 65-2640RK-05	65-2641RK 65-2641RK-05	65-2643RK-05	65-2645RK-05	65-2646RK-05	65-2649RK-CH4 65-2658RK-CH4	65-2649RK-HC	65-2660RK-02 65-2660RK-03 65-2660RK-05 65-2660RK-10
Sensors	Catalytic		Galvanic cell	Electrochemical		Infrared
Measuring Ranges	0 - 100 % LEL	0 - 25.0% Vol.	0 - 100 ppm	0 - 300 ppm	0 - 100% LEL 0 - 100% Vol.	0 - 100% LEL	-02	0 - 5000 ppm
							-03 -05	0 - 5% Vol. 0 - 50% Vol.
							-10	0 - 100% Vol.
Resolution	1% LEL		0.1% Vol.	1 ppm		1% LEL / 1% Vol.		20 ppm / 0.1% Vol. / 1% Vol.
Lower Detectable Limit (LDL)	2% of full scale		0.1% Vol.	2% of full scale
Max Current Draw (24VDC)	160 mA with alarm 1 and alarm 2 active and all relays energized		125 mA with alarm 1 and alarm 2 active and all relays energized
Response Time (T-90)	35 Seconds or less					30 Seconds or less
Life Expectancy	2 to 3 years with normal service	3 to 5 years with normal service	2 to 3 years with normal service			5 years plus with normal service
Accuracy (which ever is greater)	± 5% of reading or ± 2 % LEL		± 0.5% Vol. O2	± 5% of reading or ± 2 ppm H2S	± 5% of reading or ± 5 ppm CO	± 5% of reading or ± 2 % of full scale
Weather Resistant	Patented water repellent sensor coating
Alarms
Alarm Settings	Two fully programmable alarm set points, increasing / decreasing, latching / self-resetting, on delays, off delays, normally energized or de-energized
Alarm Indication	Visual LEDs. Alarm 1, Amber; Alarm 2, Red; Fail, Red
Relays	5 amp form ‘C’ contacts for alarm 1, alarm 2, and fail
Physical
Dimensions	Height: 8.5” (215 mm), Width: 5.2” (132 mm), Depth: 4.5” (114 mm)
Display	Alphanumeric OLED display. 8 characters per line; 2 lines for gas concentration readout, plus user-friendly calibration and setup
Enclosure	Explosion proof for Class I, Div 1, Groups B, C, D.
Enclosure Rating	NEMA 4X, explosion proof, watertight, cast aluminum with o-ring seal and epoxy powder coating
Controls	Magnet used for calibration functions. Calibrates without opening the housing. Internal push-button controls also available for calibration and setup
Operating Environment
Operating Temperature	-40^°F to 167^°F -40^°C to 75^°C		-4^°F to 113^°F -20^°C to 45^°C	-40^°F to 104^°F -40^°C to 40^°C	23^°F to 104^°F -5^°C to 40^°C	-40^°F to 122^°F -40^°C to 50^°C
Relative Humidity	5 - 95% RH non-condensing
Location	Indoor or outdoor. Explosion proof for Class I, Div. 1, Groups B, C, D.
Operating Voltage	10 VDC - 30 VDC
Outputs
Analog	Linear 4-20 mA signal, into 1000 ohms impedance max (24DC), 0 - 500 ohms max (12VDC) corresponding to 0 - full scale
Digital	Modbus RTU output standard, fully configurable, 2-wire RS-485, 1200 to 19.2k baud
Approvals	65-2640RK UL 65-2640RK-05 C CSA US	65-2641RK UL 65-2641RK-05 C CSA US	C CSA US			C UL US
Controllers	Compatible with all RKI Beacon controllers, as well as most DCS / PLC systems : Beacon 110, Beacon 200, Beacon 410, Beacon 800
Warranty	One year material and workmanship