RKI Instruments 65-2670-XX-04 User manual

RKI Instruments, Inc.
www.rkiinstruments.com
65-2670-XX-04
M2A Transmitter
Operator’s Manual
Part Number: 71-0518
Revision: D
Released: 6/24/21

65-2670-XX-04 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.

65-2670-XX-04 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

65-2670-XX-04 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 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
Overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
External Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
Internal Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
Chapter 3: Installation & Startup . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16
Overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16
Mounting the M2A Transmitter . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16
Wiring the M2A Transmitter . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18
Start Up . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21
Chapter 4: Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24
Overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24
Normal Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24
Information Screen . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24
4 - 20 mA Signal Output Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25
Alarm Indications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26
Chapter 5: Configuration Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29
Overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29
Viewing & Changing M2A Parameters . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29
Chapter 6: Gas Type Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32
Overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32
Selecting the Gas Type . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32

65-2670-XX-04 M2A Transmitter Operator’s Manual
Chapter 7: Maintenance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 35
Overview. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 35
Preventive Maintenance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 35
Troubleshooting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 35
Calibration Frequency. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 37
Calibration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 38
Replacing Components of the Detector . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 41
Chapter 8: RS-485 Modbus Output . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 44
Overview. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 44
Wiring the M2A in a Modbus System . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 44
Using the M2A in a 4-wire Modbus System. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 48
Modbus Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 48
Supported Modbus Functions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 50
Chapter 9: Parts List . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 55
Appendix A: Control Button Quick Reference Guide. . . . . . . . . . . . . . . . . . . . . . . . . 57
Appendix B: PLC and DCS Device Wiring . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 58
Appendix C: Function Code 16 Registers. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 60

6 65-2670-XX-04 M2A Transmitter Operator’s Manual
Chapter 1: Introduction
Overview
This chapter briefly describes the 65-2670-XX-04 M2A Transmitter. This chapter also describes the
65-2670-XX-04 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.

65-2670-XX-04 M2A Transmitter Operator’s Manual 7
Specifications
Table 1 lists specifications for the M2A.
Table 1: M2A Specifications
Target Gas/Detection Range • 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
•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 - 3.00 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
• 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
Sampling Method Diffusion
Flow Rate for Calibration 0.25 LPM (using a 0.5 LPM regulator that is normally recommended for
M2As will result in an inaccurate calibration)
Input Power 10 - 30 VDC
Controls • Three push button switches
• Three magnetic switches for non-intrusive calibration
Weight 5.5 lbs.
Signal Output • 4 to 20 mA with impedance maximums listed below
-12 VDC: 500 ohms impedance max
-24 VDC: 1000 ohms impedance max
• RS-485 Modbus
Operating Temperature -20°C to 40°C
Accuracy ± 10% of reading or ± 5% of full scale (whichever is greater)
*These are the RKI factory settings. You can change the alarm settings in Configuration Mode. See
“Viewing & Changing M2A Parameters” on page 29.

8 65-2670-XX-04 M2A Transmitter Operator’s Manual
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.

65-2670-XX-04 M2A Transmitter Operator’s Manual 9
Chapter 2: Description
Overview
This chapter describes the components of the M2A transmitter. The transmitter is a 4 - 20 mA type
detector head. It consists of the detector, calibration adapter/splash guard, terminal PCB, the M2A
junction box, and the detector junction box. The two-junction-box configuration is intended for
situations where the detector needs to be installed at an inaccessible location. The detector junction
box can be installed at the inaccessible location and the M2A junction box can be installed in a more
readily accessible area.
External Description
This section describes the junction boxes and all external components of the M2A transmitter.
Magnetic
Wand
Terminal
Strip
3/4 NPT Conduit Hub
3/4 NPT
Conduit Hub
Detector
Detector
Junction Box
Calibration Adapter/
Splash Guard
M2A
Junction Box
Mounting Slot (2x)
Window
3/4 NPT
Conduit Hub
Figure 1: M2A External Components

10 65-2670-XX-04 M2A Transmitter Operator’s Manual
M2A 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 hubs to wire the remotely
installed combustible gas detector and connect wiring from an external device, typically an RKI
controller. The top hub 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 hub can be used for wiring.
WARNING: If the top conduit hub 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 18 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 allows you to access the interior of the junction box.
Detector Junction Box
The detector junction box is intended to be installed remotely from the M2A junction box. The
detector is factory installed in the bottom 3/4 NPT conduit hub. A terminal strip is provided for wiring
connections and the detector is factory wired to one side of this terminal strip. The other side of the
terminal strip is for user-supplied wiring to the detector terminal strip located in the M2A junction box.
This wiring should go through the top 3/4 NPT conduit hub. Three spacers installed on the back of the
junction box controls the distance of the junction box from a mounting surface. A ground boss near the
top conduit hub provides an external earth ground connection.
Detector
The CT-7 style detector consists of the detector housing body, detector housing cap, cap gasket, and
the plug-in sensor.
The table below outlines the M2A part numbers and replacement detector part numbers for the
detectors.
Target Gas, Range M2A Part Number Detector Used
Cl2, 0 - 3 ppm 65-2670-CL2-04 65-2302-CL2
Cl2, 0 - 10 ppm 65-2670-CL210-4 65-2302-CL2-10
ClO2, 0 - 1 ppm 65-2670-CLO2-04 65-2302-CLO2
ClO2, 0 - 3 ppm 65-2670-CLO2-34 65-2302-CLO2-3
NH3, 0 - 100 ppm 65-2670-NH3-1-4 65-2302-NH3-100
NH3, 0 - 500 ppm 65-2670-NH3-5-4 65-2302-NH3-500