RKI Instruments M2 User manual

65-2610RK-04
M2 Transmitter
Operator’s Manual
Part Number: 71-0294RK
Revision: 0
Released: 12/27/13
www.GlobalTestSupply.com
Find Quality Products Online at: [e-mail]

65-2610RK-04 M2 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.
www.GlobalTestSupply.com
Find Quality Products Online at: [e-mail]

65-2610RK-04 M2 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
www.GlobalTestSupply.com
Find Quality Products Online at: [e-mail]

65-2610RK-04 M2 Transmitter Operator’s Manual
Table of Contents
Chapter 1: Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
Overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
About the M2 Transmitter . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
About this Manual. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
Specifications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2
Chapter 2: Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
Overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
External Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
Internal Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
Chapter 3: Installation & Startup . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
Overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
Mounting the M2 Transmitter . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
Wiring the M2 Transmitter . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11
Start Up . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14
Chapter 4: Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17
Overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17
Normal Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17
Information Screen. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17
4 - 20 mA Signal Output Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18
Alarm Indications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18
Chapter 5: Configuration Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22
Overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22
Viewing & Changing M2 Parameters . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22
Chapter 6: Gas Type Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25
Overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25
Selecting the Gas Type . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25
www.GlobalTestSupply.com
Find Quality Products Online at: [e-mail]

65-2610RK-04 M2 Transmitter Operator’s Manual
Chapter 7: Maintenance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28
Overview. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28
Preventive Maintenance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28
Troubleshooting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29
Calibration Frequency. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31
Calibration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32
Replacing the Combustible Gas Detector . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34
Chapter 8: RS-485 Modbus Output . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36
Overview. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36
Wiring the M2 in a Modbus System . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36
Using the M2 in a 4-wire Modbus System . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 39
Modbus Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 39
Supported Modbus Functions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 41
Parts List . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 46
Appendix A: Control Button Quick Reference Guide. . . . . . . . . . . . . . . . . . . . . . . . . . . . 47
Appendix B: PLC and DCS Device Wiring . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 48
Appendix C: Function Code 16 Registers. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 50
(Appendix C available from RKI Instruments, Inc. Not included in manual as normally
provided with M2 detector head.)
www.GlobalTestSupply.com
Find Quality Products Online at: [e-mail]

1 65-2610RK-04 M2 Transmitter Operator’s Manual
Chapter 1: Introduction
Overview
This chapter briefly describes the 65-2610RK-04 M2 Transmitter. This chapter also
describes the 65-2610RK-04 M2 Transmitter Operator’s Manual (this document). Table 1 at
the end of this chapter lists the specifications for the M2.
About the M2 Transmitter
The M2 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 M2 displays the current gas reading on an LCD 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 M2 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 M2 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.
www.GlobalTestSupply.com
Find Quality Products Online at: [e-mail]

65-2610RK-04 M2 Transmitter Operator’s Manual 2
Specifications
Table 1 lists specifications for the M2.
WARNING: When using the M2, you must follow the instructions and warnings in
this manual to assure proper and safe operation of the M2 and to
minimize the risk of personal injury. Be sure to maintain and periodically
calibrate the M2 as described in this manual.
WARNING: M2 detector heads with firmware version 5.0 or later have a different
Modbus register assignment than M2s with previous versions of
firmware. If you are adding M2s with firmware version 5.0 or later to an
existing Modbus network installation, confirm what firmware version is
installed in the M2s already in the network and if necessary, take all steps
required to address the differences in Modbus register assignments. See
“Supported Modbus Functions” on page 41 for information on the current
Modbus register assignments. The firmware version is shown on the
Information Screen described on page 17.
Table 1: M2 Specifications
Target Gas/Detection Range Combustible Gas (methane calibration standard):
0 - 100% LEL, 1% LEL increments
Alarm Settings
(Alarm 1/Alarm 2) 10 %LEL/50 %LEL
Construction (housing) Explosion-proof Junction Box, NEMA 4
Area Classification Explosion-proof for Class I, Groups B, C, and D
Sampling Method Diffusion
Input Power 19 - 30 VDC
Controls • Three push button switches
• Three magnetic switches for non-intrusive calibration
Weight 5.5 lbs.
Signal Output • 4 to 20 mA, 500 ohms impedance max
• RS-485 Modbus
Operating Temperature -20°C to 50°C
Accuracy ± 5% of reading or ± 2% LEL (whichever is greater)
*These are the RKI factory settings. You can change the alarm settings in Configuration Mode. See
“Viewing & Changing M2 Parameters” on page 22.
www.GlobalTestSupply.com
Find Quality Products Online at: [e-mail]

3 65-2610RK-04 M2 Transmitter Operator’s Manual
Chapter 2: Description
Overview
This chapter describes the components of the M2 transmitter. The transmitter is a 4 - 20
mA type detector head. It consists of the combustible gas detector, calibration adapter/
splash guard, terminal PCB, the M2 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 M2 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 M2
transmitter.
Figure 1: M2 External Components
Magnetic
Wand
Terminal
Strip
3/4" NPT Conduit Hub
3/4" NPT ConduitHub
Detector
Junction Box
Calibration Adapter/
Splash Guard
Combustible Gas
Detector
M2 Junction Box
Window
Mounting Slot (2x)
www.GlobalTestSupply.com
Find Quality Products Online at: [e-mail]

65-2610RK-04 M2 Transmitter Operator’s Manual 4
M2 Junction Box
The M2’s cast aluminum junction box protects the terminal PCB and wiring connections
made to the terminal PCB. Use the top 3/4’’ conduit hub to connect wiring from the
terminal PCB to external power and/or to an external device, typically an RKI controller.
Use the bottom 3/4” conduit hub to wire the remotely installed combustible gas detector.
Use the junction box’s two mounting slots to mount the M2 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 LCD 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 M2 junction box.
The combustible gas detector is factory installed in the bottom 3/4” NPT conduit hub
using a 3/4 in. x 1/2 in. NPT reducer. 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 M2
junction box. This wiring should go through the top 3/4” conduit hub. Three spacers
installed on the back of the junction box controls the distance of the junction box from a
mounting surface.
Combustible Gas Detector
The combustible gas detector is a catalytic type detector that produces an electrical output
that corresponds to the detection range. It is packaged in a 1/2 inch NPT nipple with a
sintered metal flame arrestor on one end allowing ambient air to diffuse into the detector.
The flame arrestor also contains any sparks which may occur within the detector. The 1/2
inch NPT mounting threads at the top of the detector allow you to mount it into the
bottom conduit hub of the junction box. The junction box conduit hub is 3/4” NPT, so a
3/4 in. x 1/2 in. NPT reducer is used to install the combustible gas detector. A rainshield
screws onto the bottom of the detector (flame arrestor end). The rainshield helps protect
the detector from rain and debris in the monitoring environment. Four color-coded leads
extend from the top of the detector. The leads allow you to connect the detector to the
terminal strip.
Calibration Adapter/Splash Guard
A calibration adapter/splash guard is installed on the combustible gas detector. A fitting
at the bottom of the calibration adapter/splash guard allows a length of tubing to be
connected for calibration and routed to a more easily accessible location (near the M2
junction box is optimal for ease of calibration). The calibration adapter/splash guard also
protects the detector from splashing water or direct water spray.
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.
www.GlobalTestSupply.com
Find Quality Products Online at: [e-mail]

5 65-2610RK-04 M2 Transmitter Operator’s Manual
Internal Description
This section describes the internal components of the M2. The internal components of the
M2 include the terminal PCB which provides for all the wiring connections to the M2 and
the control PCB which displays the gas reading and has the control buttons.
Figure 2: M2 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 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 LCD 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 M2 to a Modbus network. The
terminal PCB also controls three relays, one fail and two gas alarm relays.
Two columns of plug-in style terminal strips are used to make all wiring connections to
the M2. 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
Alarm 1 LED
Fail LED
TX LED
RX LED
Alarm 2 LED
UP/YES
ENTER
LCD Display
ENTER
DOWN/NO
Push Button
Control Switches
C NC NO
ALARM 1
LEL
R W G B
R W G B
FAIL
C NC NO
PWR/SIG
- S +
- S +
Detector Terminal Strip
Power/Signal
Terminal Strip
Programming
Connector
(Factory Use)
Detector
Current Pot
(Factory
Adjust)
UP/YES
DOWN/NO
Termination
Jumper
View With Cover Removed
Modbus
Terminal Strip
View With Cover and
Control PCB Removed
Display
Ribbon Cable
Connector
3/4" NPT Conduit Opening
for Wire Entry
LEL PWR/SIG
RKI INSTRUMENTS
M2 TRANSMITTER
A B C
R S 485
A B C
RS485
ALARM 2
C NC NO
Relay
Terminal
Strips
Junction Box
Magnetic
Switches
Terminal PCB
Control PCB
3/4" NPT Conduit
Opening for
Detector J-Box
Wiring
www.GlobalTestSupply.com
Find Quality Products Online at: [e-mail]