RKI Instruments 65-2646RKS-SW User manual

RKI Instruments, Inc.
www.rkiinstruments.com
65-2646RKS-SW
M2A Transmitter
Operator’s Manual
Part Number: 71-0601
Revision: P1
Released: 8/8/22

2• 65-2646RKS-SW 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. For most
applications, typical calibration frequencies are between 3 and 6
months but can be more often or less often based on your usage.

65-2646RKS-SW M2A 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• 65-2646RKS-SW 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 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .8
Overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
External Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
Internal Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11
Chapter 3: Installation & Startup . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .16
Overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16
Mounting the M2A Transmitter . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16
Wiring the M2A Transmitter . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17
Start Up . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20
Chapter 4: Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .23
Overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23
Normal Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23
Information Screen . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23
4 - 20 mA Signal Output Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24
Alarm Indications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24
Chapter 5: Configuration Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .28
Overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28
Viewing & Changing M2A Parameters . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28
Chapter 6: Gas Type Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .31
Overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31
Selecting the Gas Type . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31

65-2646RKS-SW M2A Transmitter Operator’s Manual • 5
Chapter 7: Maintenance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .34
Overview. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34
Preventive Maintenance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34
Troubleshooting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34
Calibration Frequency. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36
Calibration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36
Replacing Components of the CO Detector . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 39
Chapter 8: RS-485 Modbus Output. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .42
Overview. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 42
Wiring the M2A in a Modbus System . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 42
Using the M2A in a 4-wire Modbus System. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 46
Modbus Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 46
Supported Modbus Functions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 48
Chapter 9: Parts List . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .54
Appendix A: Control Button Quick Reference Guide . . . . . . . . . . . . . . . . . . . .55
Appendix B: PLC and DCS Device Wiring. . . . . . . . . . . . . . . . . . . . . . . . . . . . .56
Appendix C: Function Code 16 Registers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .58

6• Chapter 1: Introduction 65-2646RKS-SW M2A Transmitter Operator’s Manual
Chapter 1: Introduction
Overview
This chapter briefly describes the 65-2646RKS-SW M2A Transmitter. This chapter also describes
the 65-2646RKS-SW 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.

65-2646RKS-SW M2A Transmitter Operator’s Manual Chapter 1: Introduction • 7
Specifications
Table 1 lists specifications for the M2A.
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.
Table 1: M2A Specifications
Target Gas/Detection Range Carbon monoxide: 0 - 300 ppm, 1 ppm increments
Alarm Settings (Alarm 1/Alarm 2)* 25 ppm/50 ppm
Construction (housing) Explosion-proof junction box, NEMA 4X
Area Classification Explosion-proof for Class I, Groups B, C, and D
Sampling Method Diffusion
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 -40°C to +50°C
Accuracy ± 5% of reading or ± 5 ppm CO (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 28.

8• Chapter 2: Description 65-2646RKS-SW M2A Transmitter Operator’s Manual
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 CO detector, terminal PCB, and the junction box.
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 hubs to mount the
detector to the junction box (factory installed in the bottom port) 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.
Magnetic
Wand
Junction Box Cover
Detector
Mounting Slot (2x)
Window
3/4 NPT
Conduit Port
3/4 NPT Conduit Port, Plugged

65-2646RKS-SW M2A Transmitter Operator’s Manual Chapter 2: Description • 9
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 17 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.
CO Detector
The CO detector consists of the detector housing body, detector housing cap, cap gasket, charcoal
filter with rubber boot, and the plug-in sensor.
Figure 2: CO Detector Component Location
Detector Housing Body
The detector housing body protects the electronic components within the housing. Use the
mounting threads at the top of the housing to screw the CO detector into the 3/4 NPT hub on the
bottom of the detector junction box. Two wires extend from the top of the detector housing body.
Use these wires to connect the CO detector to the terminal strip. One of the wires is red and one of
the wires is black.
The housing includes a four-socket pattern. This socket pattern accepts the sensor’s four pins to
secure the sensor within the detector housing. A pre-amplifier, located between the sockets and
two interconnect wires, conditions the sensor’s signal before the signal reaches the controller.
Plug-In CO Sensor
Rubber Boot With
Charcoal Filter
Detector Housing Cap
Detector Housing Body
Cap Gasket
Flame Arrestor
Guard

10 • Chapter 2: Description 65-2646RKS-SW M2A Transmitter Operator’s Manual
Housing Cap & Cap Gasket
The housing cap screws onto the detector housing. It retains the plug-in sensor and protects it
from damage. The housing cap also includes a flame arrestor which contains any sparks that may
occur within the detector and a flame arrestor guard which protects the flame arrestor from
damage. Unscrew the detector cap to access the plug-in sensor for maintenance or replacement. A
cap gasket seals the interface between the housing and cap. A flame arrestor guard is permanently
bonded to the cap.
Charcoal Filter and Rubber Boot
The disc-shaped charcoal filter is secured to the face of the CO sensor with a rubber boot. The
charcoal filter prevents interference gases (hydrogen sulfide [H2S] and certain hydrocarbons)
from producing false CO readings.
Plug-In CO Sensor
The sensor is secured within the detector assembly by the housing cap. Through a series of
chemical and electrical reactions, the sensor produces an electrical output that corresponds to the
detection range of the transmitter.
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.