RKI Instruments M2A User manual

M2A Transmitter
Operator’s Manual
Part Number: 71-0305RK
Revision: R
Released: 3/10/21
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M2A 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. Typical calibration frequencies for most applications are
between 3 and 6 months, but can be required more often or less often based on
your usage.
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M2A Transmitter Operator’s Manual
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:
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 A PARTICULAR PURPOSE. IN NO 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.
a) Absorbent cartridges d) Batteries
b) Pump diaphragms and valves e) Filter elements
c) Fuses
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M2A Transmitter Operator’s Manual
Table of Contents
Chapter 1: Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
Overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
About the M2A Transmitter . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
About this Manual . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
Specifications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
Chapter 2: Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
Overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
External Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
Internal Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18
Chapter 3: Installation & Startup . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22
Overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22
Mounting the M2A Transmitter . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22
Wiring the M2A Transmitter . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28
Start Up . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 35
Chapter 4: Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 37
Overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 37
Normal Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 37
Information Screen . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 37
4 - 20 mA Signal Output Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 37
Alarm Indications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 38
Chapter 5: Configuration Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 42
Overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 42
Viewing & Changing M2A Parameters . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 42
Chapter 6: Gas Type Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 45
Overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 45
Selecting the Gas Type . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 45
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M2A Transmitter Operator’s Manual
Chapter 7: Maintenance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 48
Overview. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 48
Preventive Maintenance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 48
Troubleshooting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 48
Calibration Frequency. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 50
Calibration, Combustible Gas, CO2, and Toxic Versions . . . . . . . . . . . . . . . 50
Calibration, Oxygen Version . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 54
Replacing Components of the M2A . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 56
Chapter 8: RS-485 Modbus Output . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 61
Overview. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 61
Wiring the M2A in a Modbus System . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 61
Using the M2A in a 4-wire Modbus System. . . . . . . . . . . . . . . . . . . . . . . . . . 64
Modbus Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 64
Supported Modbus Functions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 66
Chapter 9: Parts List . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 71
Appendix A: Control Button Quick Reference Guide. . . . . . . . . . . . . . . . . . . . . . 76
Appendix B: PLC and DCS Device Wiring . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 77
Appendix C: Function Code 16 Registers. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 79
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6M2A Transmitter Operator’s Manual
Chapter 1: Introduction
Overview
This chapter briefly describes the M2A Transmitter. This chapter also describes the M2A Transmitter Operator’s
Manual (this document). Table 1 at the end of this chapter lists the specifications for the M2A.
About the M2A Transmitter
The M2A 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 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 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 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.
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M2A Transmitter Operator’s Manual 7
Specifications
Table 1 lists specifications for the M2A.
Table 1: M2A Specifications
Target Gas/
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)
•IRCH
4Volume: 0 - 5.00% volume, 0.01% increments
•IRCH
4Volume: 0 - 100 % volume, 1% increments
•IRCO
2ppm: 0 - 5,000 ppm, 20 ppm increments
•IRCO
2ppm: 0 - 10,000 ppm, 20 ppm increments
•IRCO
2Volume: 0 - 5.00 % volume, 0.01% increments
•IRCO
2Volume: 0 - 50.0 % volume, 0.1% increments
•IRCO
2Volume: 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
Tox ic
• 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 (Cl2): 0 - 3.00 ppm, 0.01 ppm increments
• Chlorine (Cl2): 0 - 5.00 ppm, 0.01 ppm increments
• Chlorine (Cl2): 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
• Sulphur Dioxide (SO2): 0 - 6.00 ppm, 0.01 ppm increments
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%
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8M2A Transmitter Operator’s Manual
Alarm Settings
(Alarm 1/Alarm 2)*,
cont’d
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: 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
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
Tox ic (CT-7 Seri es) 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
Table 1: M2A Specifications
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M2A Transmitter Operator’s Manual 9
WARNING: When using the M2A, you must follow the instructions and warnings in this manual to
assure proper and safe operation of the M2A and to minimize the risk of personal injury. Be
sure to maintain and periodically calibrate the M2A as described in this manual.
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 Parameters” on page 42 to change the alarm settings.
**Independent of zero drift.
Table 1: M2A Specifications
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10 M2A Transmitter Operator’s Manual
Chapter 2: Description
Overview
This chapter describes external and internal components of the M2A Transmitter.
External Description
This section describes the junction box and all external components of the M2A transmitter.
Figure 1: M2A External Components
Junction Box
The M2A’s cast aluminum junction box is dust and weather resistant. The junction box also protects the M2A
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 Transmitter” on page 28 for complete wiring
instructions.
Use the junction box’s two mounting holes to mount the M2A to a vertical surface at the monitoring site. The
window in the cover on the front of the junction box allows you to view the OLED display and use the magnetic
wand to actuate the magnetic control switches so you can perform non-intrusive calibration. Removing the cover
Magnetic
Wand
Junction Box Cover 3/4 NPT Conduit Port, Plugged
3/4 NPT
Conduit Port
Window
Mounting Slot (2x)
Detector
(Catalytic LEL Detector Shown)
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M2A Transmitter Operator’s Manual 11
allows you to access the interior of the junction box.
Magnetic Wand
The magnetic wand is a short plastic rod with a magnet in one end. It is used to actuate the magnetic control
switches on the control PCB while the junction box cover is still installed so that non-intrusive calibration can be
performed.
Gas Detector
The gas detector senses the target gas and is mounted in a 3/4 NPT conduit port on the right bottom side of the
M2A. A variety of detectors may be used with the M2A. See the sections below for descriptions of each type of
detector.
Catalytic Detectors
The catalytic detectors have a 1/2 NPT thread and require a 3/4 NPT x 1/2 NPT reducer to install in the detector
port.
The table below outlines the M2A part numbers and replacement detector part numbers for the catalytic
detectors.
Table 2: Catalytic Detectors
Figure 2: Catalytic Sensors
Target Gas, Range M2A Part Number Detector Used
Combustible Gas, 0 - 100% LEL 65-2640RK 61-0140RK (Catalytic UL version)
65-2640RK-05 61-0140RK-05 (Catalytic CSA version)
Hydrogen, 0 - 100% LEL 65-2641RK NC-6205-01 (Catalytic UL version, hydrogen specific)
65-2641RK-05 NC-6205-05 (Catalytic CSA version, hydrogen specific)
Methane, 0 - 9000 ppm 65-2647RK 61-0140RKA (Catalytic UL version)
65-2647RK-05 61-0140RKA-05 (Catalytic CSA version)
Detector Part Numbers
61-0140RK
61-0140RKA
NC-6205-01
UL Version
Detector PartNumbers
61-0140RK-05
61-0140RKA-05
NC-6205-05
CSA Version
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12 M2A Transmitter Operator’s Manual
Infrared (IR) Detectors
The IR combustible detectors are generally used instead of the catalytic combustible detectors in applications
where there may be catalyst poisons such as silicone present or where oxygen is not present in the monitoring
environment.
The table below outlines the M2A part numbers and replacement detector part numbers for the infrared (IR)
detectors.
Table 3: Infrared (IR) Detectors
Target Gas, Range M2A Part Number Detector Used
CH4, 0 - 100% LEL 65-2649RK-CH4 61-0190RK-CH4 (UL)
65-2664RK-CH4 61-0197RK-CH4
CH4, 0 - 5.00% volume 65-2649RK-CH4-5 61-0190RK-CH4 (UL)
CH4, 0 - 100% volume 65-2658RK-CH4 61-0192RK-CH4 (UL)
65-2665RK-CH4 61-0199RK-CH4
CO2, 0 - 5,000 ppm 65-2660RK-02 61-0191RK-02 (UL)
65-2661RK-02 61-0198RK-02
CO2, 0 - 9,000 ppm 65-2660RK-01 61-0191RK-01 (UL)
65-2661RK-01 61-0198RK-01
CO2, 0 - 5% volume 65-2660RK-03 61-0191RK-03 (UL)
65-2661RK-03 61-0198RK-03
CO2, 0 - 50% volume 65-2660RK-05 61-0191RK-05 (UL)
65-2661RK-05 61-0198RK-05
CO2, 0 - 100% volume 65-2660RK-10 61-0191RK-10 (UL)
65-2661RK-10 61-0198RK-10
HC, 0 - 100% LEL (cal. to propane) 65-2649RK-HC 61-0190RK-HC (UL)
65-2664RK-HC 61-0197RK-HC
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M2A Transmitter Operator’s Manual 13
Figure 3: Infrared (IR) Sensors
Oxygen Detectors
There are three types of oxygen detectors available: a non-explosion proof partial pressure type, a non-explosion
proof capillary type with a replaceable sensor, and an explosion proof (CSA) capillary type with a replaceable
sensor. The capillary type’s output is less susceptible to variations in atmospheric pressure than the partial
pressure type. The CSA type oxygen detector (65-2514RK) and the non-explosion proof capillary type detector
(65-2494RK) has a replaceable plug-in sensor inside the detector housing. The entire oxygen detector must be
removed if replacement is required for the 65-2510RK.
The table below outlines the M2A part numbers and replacement detector part numbers for the oxygen detectors.
Table 4: Oxygen Detectors
Target Gas, Range M2A Part Number Detector Used
Oxygen, 0 - 25% 65-2643RK-05 65-2514RK (capillary, CSA)
65-2644RK 65-2510RK (partial pressure)
65-2666RK 65-2494RK (capillary)
Detector Housing Body
Cap Gasket
Plug-In IR LEL Sensor
Detector Housing Cap
Non-XP, Replaceable-Sensor Type
Hydrophobic
Membrane
XP, Non-Replaceable-
Sensor Type
Detector PartNumbers
61-0197RK-CH4
61-0197RK-HC
61-0198RK-01
61-0198RK-02
61-0198RK-03
61-0198RK-05
61-0198RK-10
61-0199RK-CH4
Detector PartNumbers
61-0190RK-CH4
61-0190RK-HC
61-0191RK-01
61-0191RK-02
61-0191RK-03
61-0191RK-05
61-0191RK-10
61-0192RK-CH4
61-0192-HC
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14 M2A Transmitter Operator’s Manual
Figure 4: Oxygen Detectors
CO and H2S Detectors
Both types of CO and H2S detectors (explosion-proof and non-explosion-proof) have replaceable plug-in sensors
inside the detector housing.
The CO detectors include a charcoal filter disk which is held onto the sensor with a rubber retaining boot. The
charcoal filter disk scrubs out interfering gases to which the CO sensor responds such as H2S and certain
hydrocarbons.
The 65-2428 and 65-2428-01 explosion-proof H2S detectors both include a rubber boot and a spacer which help
ensure that the sensor remains plugged into the detector housing body. The only difference between the 65-2428
and the 65-2428-01 is that the sensor used in the 65-2428-01 is resistant to degradation caused by frequent
exposure to low levels of H2S or occasional exposure to high levels of H2S.
The 65-2495RK non-explosion-proof H2S detector includes an adhesive-backed gasket inside the detector
housing cap which helps ensure that the sensor remains plugged into the detector housing body.
The table below outlines the M2A part numbers and replacement detector part numbers for the CO and H2S
detectors.
Table 5: CO and H2S Detectors
Target Gas, Range M2A Part Number Detector Used
CO, 0 - 300 ppm 65-2646RK-05 65-2438 (CSA)
65-2663RK 65-2496RK
CO, 0 - 200 ppm 65-2646RK-05-02 65-2438-01
CO, 0 - 100 ppm 65-2646RK-05-01 65-2438-01
H2S, 0 - 100 ppm 65-2645RK-05 65-2428 (CSA)
65-2645-05-07 65-2428-01 (CSA)
65-2662RK 65-2495RK
Cap Gasket
Detector Housing Body
Detector
Housing Cap
Hydrophobic
Membrane
Detector
Housing Cap
Plug-In Oxygen
Sensor
Cap Gasket
Non-XP, Replaceable-SensorCapillary Type Non-XP, Partial
Pressure Type
Oxygen Sensor
Detector Housing Body
Flame
Arrestor
Guard
Detector Part Number
65-2494RK Detector Part Number
65-2510RK
Detector PartNumber
65-2514RK
XP, Replaceable-Sensor CapillaryType
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M2A Transmitter Operator’s Manual 15
Figure 5: H2S Detectors
Figure 6: CO Detectors
Cap Gasket
Flame
Arrestor
Guard
H2S Plug-in Sensor
Spacer
Rubber Boot
Detector
Housing Cap
Non-XP Type
Detector
Housing Cap
Hydrophobic
Membrane
Cap Gasket
H2S Plug-in Sensor
Detector Housing Body
Detector Part Number
65-2495RK
Detector Part Numbers
65-2428
65-2428-01
Detector Housing Body
XP Type
Detector
Housing Cap
Charcoal Filter
w/Rubber Boot
CO Plug-in Sensor
Cap Gasket
Detector Housing Body
Cap Gasket
Hydrophobic
Membrane
CO Plug-in Sensor
Flame
Arrestor
Guard
Detector
Housing Cap
Non-XP Type
Detector PartNumber
65-2496RK
Detector Housing Body
Rubber Boot w/
Charcoal Filter
XP Type
Detector PartNumber
65-2438
65-2438-01
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16 M2A Transmitter Operator’s Manual
ESM-01 Detectors
The construction of the various ESM-01 detectors is similar. Each of the ESM-01 detectors has a different
replaceable plug-in sensor that protrudes through the detector housing cap. Although ESM-01 detectors look the
same except for the plug-in detector, the detector housing which includes the detector socket and conditioning
circuitry is specific to a sensor type. For example, a detector housing from a Cl2detector cannot be used with an
NH3detector. One of the two detector wires is color coded for each specific detector type. The ESM-01 detectors
include a removable splashguard that screws onto the detector housing cap. When it is necessary to apply gas to
an ESM-01 detector, remove the splashguard to allow access to the sensor that protrudes through the detector
housing cap. You can then push the appropriate ESM-01 calibration cup onto the sensor.
The table below outlines the M2A part numbers and replacement detector part numbers for the ESM-01
detectors.
Table 6: ESM-01 Detectors
Figure 7: ESM-01 Type Detector
Target Gas, Range M2A Part Number Detector Used
AsH3, 0 - 1.5 ppm 65-2648RK-ASH3 65-2300RK-ASH3
Cl2, 0 - 3 ppm 65-2648RK-CL2 65-2300RK-CL2
Cl2, 0 - 10 ppm 65-2648RK-CL-10 65-2300RK-CL-10
HCN, 0 - 15 ppm 65-2648RK-HCN 65-2300RK-HCN
NH3, 0 - 75 ppm 65-2648RK-NH3 65-2300RK-NH3
PH3, 0 - 1 ppm 65-2648RK-PH3 65-2300RK-PH3
SO2, 0 - 6 ppm 65-2648RK-SO2 65-2300RK-SO2
Splash Guard
(removable)
Cap Gasket
Detector Housing Body
(different for each detector type)
Sensor
(different for each detector type)
Detector Housing
Cap
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M2A Transmitter Operator’s Manual 17
CT-7 Series Detectors
The CT-7 Series detectors for Cl2and ClO2have a replaceable plug-in sensor inside the detector housing. An
adhesive backed gasket inside the detector housing cap helps ensure that the sensor remains plugged into the
detector housing body.
The table below outlines the M2A part numbers and replacement detector part numbers for the CT-7 Series
detectors.
Table 7: CT-7 Series Detectors
Figure 8: CT-7 Series Detectors
Target Gas, Range M2A Part Number Detector Used
Cl2, 0 - 3 ppm 65-2670-CL2-3 65-2302-CL2-3
Cl2, 0 - 5 ppm 65-2670-CL2-5 65-2302-CL2-5
Cl2, 0 - 10 ppm 65-2670-CL2-10 65-2302-CL2-10
ClO2, 0 - 1 ppm 65-2670-CLO2-1 65-2302-CLO2-1
ClO2, 0 - 3 ppm 65-2670-CLO2-3 65-2302-CLO2-3
ClO2, 0 - 5 ppm 65-2670-CLO2-5 65-2302-CLO2-5
HCN, 0 - 15.0 ppm 65-2670-HCN-15 65-2302-HCN-15
NH3, 0 - 75.0 ppm 65-2670-NH3-75 65-2302-NH3-75
NH3, 0 - 100 ppm 65-2670-NH3-1 65-2302-NH3-1
NH3, 0 - 200 ppm 65-2670-NH3-2 65-2302-NH3-2
NH3, 0 - 500 ppm 65-2670-NH3-5 65-2302-NH3-5
Hydrophobic Membrane
Plug-in Sensor
Detector
Housing Cap
Cap Gasket
Detector Housing Body
(different for each detector type)
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18 M2A Transmitter Operator’s Manual
Internal Description
This section describes the internal components of the M2A. The internal components of the M2A include the
terminal PCB which provides for all the wiring connections to the M2A and the control PCB which displays the
gas reading and has the control buttons.
Figure 9: M2A Internal Components
Terminal PCB
The terminal PCB is encapsulated in epoxy for protection against moisture and physical damage. It is mounted
into the rear of the junction box with three standoffs and rests on a thin layer of foam. A banana jack is screwed
into each of the standoffs and is used for mounting the control PCB. The terminal PCB converts the electrical
output from the detector to a signal which can be displayed by the OLED display, a 4 - 20 mA signal (that is
proportional to the detection range), and an RS-485 Modbus output signal. The 4 - 20 mA signal may be used by
a recording device, gas monitor controller, or programmable controller. The Modbus output may be used to
connect the M2A to a Modbus network. The terminal PCB also controls three relays: one fail and two gas alarm.
Two columns of plug-in style terminal strips are used to make all wiring connections to the M2A. The column on
the left consists of the power/signal, detector, and Modbus terminal strips. The column on the right consists of
the relay terminal strips. A 20 position connector at the bottom of the terminal PCB is used to connect the
terminal PCB to the control PCB with a ribbon cable. A 5 position connector on the left side of the terminal PCB
is used by factory or field service personnel to program the M2A. On the combustible and CO2versions of the
M2A, a factory adjust pot just above the programming connector is used to set the detector current.
NO
Control PCB
Junction Box
Terminal PCB
3/4 NPT Conduit
Opening for Wire Entry
M2A TRANSMITTER
RKI INSTRUMENTS
3/4 NPT Conduit Opening, Plugged
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M2A Transmitter Operator’s Manual 19
Figure 10: Terminal PCB Component Location
Power/Signal Terminal Strip
The power/signal terminal strip is a three position plug-in style terminal strip located at the top of the left
terminal column. It is used to connect 24 VDC power to the M2A and to connect the 4 - 20 mA output signal to a
device.
The signal output, the S terminal, does not have to be connected for the M2A to function. The S terminal is used
if you want to connect the 4 - 20 mA output signal to another device such as a gas monitoring controller, chart
recorder, or programmable controller (PLC).
Detector Terminal Strip
The detector terminal strip is a four position plug-in style terminal strip and is the middle terminal strip in the left
terminal column. For a combustible or CO2M2A, all four terminals are used to connect the detector to the M2A.
For a toxic or oxygen M2A, only two of the terminals are used for connecting a detector; two terminals are
dedicated for connecting a toxic detector and two are dedicated for connecting an oxygen detector (only one
detector can be installed).
Figure 11: Detector Terminal Strip
- S +
A B C
RS 485 PWR/SIG
R W G B
LEL
C NC NO
ALARM 1 C NC NO
ALARM 2
C NC NO FAIL
Modbus Terminal Strip
Ground Jumper
Programming Connector
(Factory Use)
Power/Signal Terminal Strip
Termination Jumper
Ribbon Cable Connector
Detector Current Adjust Pot
(Comb/CO2 Type Only, Factory Adjust)
Detector Terminal Strip
(Comb/CO2 Version Shown) Relay
Terminal
Strips
Toxic/Oxy
Detector
Terminal
Strip
Comb/CO2
Detector
Terminal
Strip
- S +
PWR/SIG
TOXIC OXY
+ - + -
RS 485
A B C
C NC NO
ALARM 1 C NC NO
ALARM 2
C NC NO FAIL
- S +
A B C
RS 485 PWR/SIG
R W G B
LEL C NC NO
ALARM 1 C NC NO
ALARM 2
C NC NO FAIL
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20 M2A Transmitter Operator’s Manual
NOTE: The detector is factory-wired to the M2A. See “Wiring the M2A Transmitter” on page 28 for all
wiring procedures related to M2A.
Modbus Terminal Strip
The Modbus terminal strip is a three position plug-in style terminal strip and is the bottom terminal strip in the
left terminal column. It allows connection of the M2A into a Modbus network.
Relay Terminal Strips
The right column of terminal strips consists of, from top to bottom, the fail, alarm 1, and alarm 2 relay terminal
strips. They are three-position plug-in style terminal strips. The relay terminal strips are used to connect devices
such as lights and horns that are controlled by the relay contacts. The relay contacts are rated at 115 VAC, 5
amps. The relay contacts may also be used to control higher rated relays.
Termination Jumper
A two pin header with a termination jumper installed is located below the Modbus terminal strip. Leave this
jumper installed unless directed to remove it for a Modbus installation. See “Chapter 8: RS-485 Modbus Output”
on page 61 for a description of using the M2A in a Modbus system.
Ground Jumper
A two pin header with a jumper installed is located along the left side of the terminal PCB. Leave this jumper
installed unless directed to remove it for a Modbus installation. See “Chapter 8: RS-485 Modbus Output” on
page 61 for a description of using the M2A in a Modbus system.
Control PCB
The OLED display and control switches are located on the control PCB. It is installed on top of the terminal PCB
by lining up its three spacing standoffs with the banana jacks in the terminal PCB mounting standoffs and
pushing it onto the banana jacks. The jacks retain the control PCB.
Figure 12: Control PCB Component Location
ENTER
DOWN/NO
UP/YES
Push Button
Control Switches
Magnetic Switches
ENTER
UP/YES
DOWN/NO
Alarm 1 LED Alarm 2 LED
Fail LED RX LED
TX LED
M2ATRANSMITTER
RKI INSTRUMENTS
OLED Display
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