RKI Instruments M2A-XL User manual

RKI Instruments, Inc.
www.rkiinstruments.com
M2A-XL Transmitter
Operator’s Manual
Part Number: 71-0610
Revision: P1
Released: 10/20/22

2• M2A-XL Transmitter Operator’s Manual
WARNING
Read and understand this instruction manual before operating instrument.
Improper use of the gas monitor could result in bodily harm or death.
Periodic calibration and maintenance of the gas monitor is essential for proper
operation and correct readings. Please calibrate and maintain this instrument
regularly! Frequency of calibration depends upon the type of use you have and
the sensor types. For most applications, typical calibration frequencies are
between 3 and 6 months but can be more often or less often based on your
usage.

M2A-XL Transmitter Operator’s Manual • 3
Product Warranty
RKI Instruments, Inc. warrants gas alarm equipment sold by us to be free from defects in
materials, workmanship, and performance for a period of one year from date of shipment from
RKI Instruments, Inc. Any parts found defective within that period will be repaired or replaced, at
our option, free of charge. This warranty does not apply to those items which by their nature are
subject to deterioration or consumption in normal service, and which must be cleaned, repaired, or
replaced on a routine basis. Examples of such items are:
• Absorbent cartridges
• Pump diaphragms and valves
•Fuses
•Batteries
• Filter elements
Warranty is voided by abuse including mechanical damage, alteration, rough handling, or repair
procedures not in accordance with the operator’s manual. This warranty indicates the full extent
of our liability, and we are not responsible for removal or replacement costs, local repair costs,
transportation costs, or contingent expenses incurred without our prior approval.
THIS WARRANTY IS EXPRESSLY IN LIEU OF ANY AND ALL OTHER WARRANTIES AND
REPRESENTATIONS, EXPRESSED OR IMPLIED, AND ALL OTHER OBLIGATIONS OR
LIABILITIES ON THE PART OF RKI INSTRUMENTS, INC. INCLUDING BUT NOT LIMITED TO,
THE WARRANTY OF MERCHANTABILITY OR FITNESS FOR APARTICULAR PURPOSE. INNO
EVENT SHALL RKI INSTRUMENTS, INC. BE LIABLE FOR INDIRECT, INCIDENTAL, OR
CONSEQUENTIAL LOSS OR DAMAGE OF ANY KIND CONNECTED WITH THE USE OF ITS
PRODUCTS OR FAILURE OF ITS PRODUCTS TO FUNCTION OR OPERATE PROPERLY.
This warranty covers instruments and parts sold to users by authorized distributors, dealers, and
representatives as appointed by RKI Instruments, Inc.
We do not assume indemnification for any accident or damage caused by the operation of this gas
monitor, and our warranty is limited to the replacement of parts or our complete goods.

4• M2A-XL Transmitter Operator’s Manual
Table of Contents
Chapter 1: Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .6
Overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
About the M2A-XL Transmitter . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
About this Manual . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
Specifications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
Chapter 2: Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .10
Overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
External Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
Internal Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19
Chapter 3: Installation & Startup . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .25
Overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25
Mounting the M2A-XL Transmitter . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25
Wiring the M2A-XL Transmitter . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30
Start Up . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 38
Chapter 4: Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .41
Overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 41
Normal Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 41
Information Screen . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 41
4 - 20 mA Signal Output Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 42
Alarm Indications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 43
Chapter 5: Configuration Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .47
Overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 47
Viewing & Changing M2A-XL Parameters . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 47
Chapter 6: Gas Type Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .51
Overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 51
Selecting the Gas Type . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 51
Chapter 7: Maintenance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .55
Overview. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 55
Preventive Maintenance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 55
Troubleshooting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 56
Calibration Frequency. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 58
Calibration, Combustible Gas, CO2, and Toxic Versions . . . . . . . . . . . . . . . . . . . . . . . . 58

M2A-XL Transmitter Operator’s Manual • 5
Calibration, Oxygen Version . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 63
Replacing Components of the M2A-XL . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 66
Chapter 8: RS-485 Modbus Output. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .73
Overview. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 73
Wiring the M2A-XL in a Modbus System . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 73
Using the M2A-XL in a 4-wire Modbus System . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 77
Modbus Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 77
Supported Modbus Functions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 79
Chapter 9: Parts List . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .85
Appendix A: Control Button Quick Reference Guide . . . . . . . . . . . . . . . . . . . .91
Appendix B: PLC and DCS Device Wiring. . . . . . . . . . . . . . . . . . . . . . . . . . . . .92
Appendix C: Function Code 16 Registers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .94

6• Chapter 1: Introduction M2A-XL Transmitter Operator’s Manual
Chapter 1: Introduction
Overview
This chapter briefly describes the M2A-XL Transmitter. This chapter also describes the M2A-XL
Transmitter Operator’s Manual (this document). Table 1 at the end of this chapter lists the
specifications for the M2A-XL.
About the M2A-XL Transmitter
The M2A-XL transmitter is a fixed mount, continuous-monitoring detector head. All user
adjustable parameters may be accessed using push button switches. In addition, calibration may
be performed non-intrusively by use of a magnetic wand accessory which activates magnetic
switches through a window at the front face of the detector head.
The M2A-XL displays the current gas reading on an OLED display which is visible through the
window in the cover (front face) and provides a 4 - 20 mA signal which indicates the target gas
reading for use by a gas monitoring controller, recording device, or programmable controller. The
M2A-XL also provides an RS-485 Modbus output. Three sets of relay contacts, two controlled by
the gas alarms and one by the fail alarm, rated at 115 VAC 5 amps are available for controlling
devices such as lights or horns or for controlling higher rated relays.
Four operating modes allow you to display and change setup and calibration settings and change
the gas type. They are Calibration Mode, Configuration Mode, Gas Type Mode, and Modbus
Mode.
About this Manual
The M2A-XL Transmitter Operator’s Manual uses the following conventions for notes, cautions,
and warnings.
NOTE: Describes additional or critical information.
CAUTION: Describes potential damage to equipment.
WARNING: Describes potential danger that can result in injury or death.

M2A-XL Transmitter Operator’s Manual Chapter 1: Introduction • 7
Specifications
Table 1 lists specifications for the M2A-XL.
Table 1: M2A-XL Specifications
Target Ga s/
Detection Range
Combustible Gas/Carbon Dioxide (CO2)
• Catalytic LEL: 0 - 100% LEL, 1% LEL increments (CH4calibration unless
otherwise specified. H2specific detector available)
• Catalytic CH4ppm: 0 - 9000 ppm, 20 ppm increments
• IR (infrared) CH4LEL: 0 - 100% LEL, 1% LEL increments
• IR HC LEL: 0 - 100% LEL, 1% LEL increments (propane calibration)
• IR CH4Volume: 0 - 5.00% volume, 0.01% increments
• IR CH4Volume: 0 - 100% volume, 1% increments
• IR CO2ppm: 0 - 5,000 ppm, 20 ppm increments
• IR CO2ppm: 0 - 10,000 ppm, 20 ppm increments
• IR CO2Volume: 0 - 5.00% volume, 0.01% increments
• IR CO2Volume: 0 - 50.0% volume, 0.1% increments
• IR CO2Volume: 0 - 100 % volume, 1% increments
Oxygen
• Oxygen (O2): 0 - 25.0% volume, 0.1% increments CO/H2S
• Carbon Monoxide (CO): 0 - 300 ppm, 1 ppm increments
• Carbon Monoxide (CO): 0 - 200 ppm, 1 ppm increments
• Carbon Monoxide (CO): 0 - 100 ppm, 1 ppm increments
• Hydrogen Sulfide (H2S): 0 - 100 ppm, 1 ppm increments
• Hydrogen Sulfide (H2S): 0 - 50 ppm, 0.1 ppm increments
Toxic
• Ammonia (NH3): 0 - 75.0 ppm, 0.1 ppm increments
• Ammonia (NH3): 0 - 100 ppm, 1 ppm increments
• Ammonia (NH3): 0 - 200 ppm, 1 ppm increments
• Ammonia (NH3): 0 - 500 ppm, 1 ppm increments
• Arsine (AsH3): 0 - 1.50 ppm, 0.01 ppm increments
•Chlorine(Cl
2): 0 - 3.00 ppm, 0.01 ppm increments
•Chlorine(Cl
2): 0 - 5.00 ppm, 0.01 ppm increments
•Chlorine(Cl
2): 0 - 10.0 ppm, 0.1 ppm increments
• Chlorine Dioxide (ClO2): 0 - 1.00 ppm, 0.01 ppm increments
• Chlorine Dioxide (ClO2): 0 - 3.00 ppm, 0.01 ppm increments
• Chlorine Dioxide (ClO2): 0 - 5.00 ppm, 0.01 ppm increments
• Hydrogen Cyanide (HCN): 0 - 15.0 ppm, 0.1 ppm increments
• Phosphine (PH3): 0 - 1.00 ppm, 0.01 ppm increments
• Sulfur Dioxide (SO2): 0 - 6.00 ppm, 0.01 ppm increments
• Sulfur Dioxide (SO2): 0 - 10.0 ppm, 0.01 ppm increments

8• Chapter 1: Introduction M2A-XL Transmitter Operator’s Manual
Alarm Settings
(Alarm 1/Alarm 2)*
Ammonia (0 - 75.0 ppm and 0 - 100 ppm): 12 ppm / 25 ppm
Ammonia (0 - 200 ppm): 25 ppm / 35 ppm
Ammonia (0 - 500 ppm): 35 ppm / 300 ppm
Arsine: 0.20 ppm / 0.50ppm
Carbon Dioxide (0 - 5,000 ppm): 2,500 ppm / 5,000 ppm
Carbon Dioxide (0 - 9,000 ppm): 2,000 ppm / 5,000 ppm
Carbon Dioxide (0 - 5.00%): 0.50% / 3.00%
Carbon Dioxide (0 - 50.0%): 50.0% / 50.0%
Carbon Dioxide (0 - 100%): 100% / 100%
Carbon Monoxide (all ranges): 25 ppm / 50 ppm
Chlorine (0 - 3.00 ppm): 0.50 ppm / 1.00 ppm
Chlorine (0 - 5.00 ppm): 0.50 ppm / 1.50 ppm
Chlorine (0 - 10.0 ppm): 1.0 ppm / 3.0 ppm
Chlorine Dioxide (0 - 1.00 ppm): 0.10 ppm / 0.30 ppm
Chlorine Dioxide (0 - 3.00 ppm): 0.30 ppm / 1.00 ppm
Chlorine Dioxide (0 - 5.00 ppm): 0.50 ppm / 1.00 ppm
Combustible Gas (%LEL): 10% LEL / 50% LEL
Combustible Gas (0-100%Volume): 100% / 100%
Hydrogen Cyanide: 5.0 ppm / 10.0 ppm
Hydrogen Sulfide (0 - 50 ppm): 5.0 ppm / 10.0 ppm
Hydrogen Sulfide (0 - 100 ppm): 10 ppm / 50 ppm
Methane (ppm): 5000 ppm / 8000 ppm
Methane (0-5.00%Volume): 0.5% / 2.5%
Oxygen: 19.5% (decreasing) / 23.5% (increasing)
Phosphine: 0.10 ppm / 0.30 ppm
Sulphur Dioxide (both ranges): 1.00 ppm / 2.00 ppm
Construction
(housing)
Explosion-proof Junction Box, NEMA 4X
Area Classification Explosion-proof for Class I, Groups B, C, and D (Combustible, CO2, CSA
Type CO and H2S, and CSA Type oxygen)
Sampling Method Diffusion
Input Power 10 - 30 VDC
Controls • Three push button switches
• Three magnetic switches for non-intrusive calibration
Weight 4.5 lbs.
Signal Output
• 4 to 20 mA with impedance maximums listed below
-12 VDC input: 500 ohms impedance max
-24 VDC input: 1000 ohms impedance max
• RS-485 Modbus
Table 1: M2A-XL Specifications

M2A-XL Transmitter Operator’s Manual Chapter 1: Introduction • 9
WARNING: When using the M2A-XL, you must follow the instructions and warnings in this
manual to assure proper and safe operation of the M2A-XL and to minimize the
risk of personal injury. Be sure to maintain and periodically calibrate the M2A-
XL as described in this manual.
Explosion Proof Non-Explosion
Proof
Operating
Temperature
Catalytic LEL/ppm -40°C to 75°C N/A
Oxygen -20°C to 45°C -20°C to 50°C
H2S -40°C to 40°C -40°C to 50°C
CO -5°C to 40°C -20°C to 50°C
Toxic (ESM-01) N/A -10°C to 40°C
Toxic (CT-7 Series) N/A -20°C to 40°C
Infrared Combustible -20°C to 50°C -40°C to 50°C
Infrared CO2-20°C to 50°C -40°C to 50°C
Accuracy
Catalytic Combustible Gas (LEL range):
± 5% of reading or ± 2% LEL (whichever is greater)
Catalytic CH4(ppm range):
± 5% of reading or ± 50 ppm (whichever is greater)**
IR Combustible Gas/IR CO2:
± 5% of reading or ± 2% of full scale (whichever is greater)
Oxygen:
± 0.5% O2
Hydrogen Sulfide:
± 5% of reading or ± 2 ppm H2S (whichever is greater)
Carbon Monoxide:
± 5% of reading or ± 5 ppm CO (whichever is greater)
Toxic Sensors (ESM-01 Type and CT-7 Series Type):
± 10% of reading or ± 5% of full scale (whichever is greater)
* These are RKI factory settings. See “Viewing & Changing M2A-XL Parameters” on page 47 to
change the alarm settings.
** Independent of zero drift
Table 1: M2A-XL Specifications

10 • Chapter 2: Description M2A-XL Transmitter Operator’s Manual
Chapter 2: Description
Overview
This chapter describes external and internal components of the M2A-XL Transmitter.
External Description
This section describes the junction box and all external components of the M2A-XL transmitter.
Figure 1: M2A-XL External Components
Junction Box
The M2A-XL’s cast aluminum junction box is dust and weather resistant. The junction box also
protects the M2A-XL and all connections made to it. Use the three 3/4 NPT conduit ports to
mount the detector to the junction box (factory installed in the bottom port) and connect wiring
from an external device (left port). The top port is shipped with a factory installed and sealed
conduit plug to avoid leaks into the junction box. If necessary, the conduit plug can be removed
and the top port can be used for wiring.
WARNING: If the top conduit port is used for wiring, be sure to seal the threads to ensure
water does not enter the junction box. See “Wiring the M2A-XL Transmitter” on
page 30 for complete wiring instructions.
Junction Box Cover
Window
Magnetic
Wand
Mounting Hole (2x)
3/4 NPT Conduit Port, Plugged
Detector
(Catalytic LEL Detector Shown)
3/4 NPT
Conduit Port