RKI Instruments M2A User Manual

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M2A Transmitter

Operator’s Manual

Part Number: 71-0305RK

Revision: P2

Released: 6/26/14

RKI Instruments, Inc.

www.rkiinstruments.com

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.

M2A Transmitter Operator’ s Manual

Product Warranty

RKI Instruments, Inc. warrants gas alarm equipment s old by us t o be free from def ects in material s, 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 warrant y does not apply to those items which by their nature are subject to deterioration or consumption in normal service, and which must b e cleaned, repaired, o r 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 N OT LIMITED T O, 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.

a) Absorbent cartridges d) Batteries b) Pump diaphragms and valves e) Filter elements c) Fuses

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.

M2A Transmitter Operator’s Manual

Table of Contents

Chapter 1: Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1

Overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1

About the M2A Transmitter . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1

About this Manual . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1

Specifications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2

Chapter 2: Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4

Overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4

External Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4

Internal Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10

Chapter 3: Installation & Startup . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14

Overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14

Mounting the M2A Transmitter . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14

Wiring the M2A Transmitter . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18

Start Up . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23

Chapter 4: Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26

Overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26

Normal Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26

Information Screen . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26

4 - 20 mA Signal Output Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27

Alarm Indications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28

Chapter 5: Configuration Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31

Overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31

Viewing & Changing M2A Parameters . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31

Chapter 6: Gas Type Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34

Overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34

Selecting the Gas Type . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34

M2A Transmitter Operator’ s Manual

Chapter 7: Maintenance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 37

Overview. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 37

Preventive Maintenance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 37

Troubleshooting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 39

Calibration Frequency. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 41

Calibration, Combustible Gas, CO2, and Toxic Versions . . . . . . . . . . . . . . . . . . . . . . . . 42

Calibration, Oxygen Version . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 45

Replacing Components of the M2A . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 47

Chapter 8: RS-485 Modbus Output . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 51

Overview. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 51

Wiring the M2A in a Modbus System . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 51

Using the M2A in a 4-wire Modbus System . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 54

Modbus Mode. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 54

Supported Modbus Functions. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 57

Parts List . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 61

Appendix A: Control Button Quick Reference Guide. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 65

Appendix B: PLC and DCS Device Wiring . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 66

Appendix C: Function Code 16 Registers. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 68

(Appendix C available from RKI Instruments, Inc. Not included in manual as normally provided with M2A detector head.)

M2A 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 Transmi tter

The M2A transmitter is a fixed mount, continuous-monitoring detector head. All user adjustable parameters may be accessed using pu sh bu tto n switc hes . 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 f ail alarm, rated at 115 VAC 5 amps are available for con trolling 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.

1 M2A Transmitter Operator’ s Manual

Specifications

Table 1 lists specif ications for the M2A.

Table 1: M2A Specifications

T ar get Gas/Detection Range Combustible Gas/Carbon Dioxide (CO

• Catalytic LEL: 0 - 10 0% L EL, 1% LEL i ncremen ts (CH4 calibration unless otherwise specified. H

specific detector available)

• IR (infrared) CH4 LEL: 0 - 100% LEL, 1% LEL increments

• IR HC LEL: 0 - 100% LEL, 1% LEL increments (propane calibration)

• IR CH

Volume: 0 - 100 % volume, 1% increments

• IR CO2 ppm: 0 - 5,000 ppm, 2 0 ppm increments

• IR CO

Volume: 0 - 5.00 % volume, 0.01% increments

Volume: 0 - 50.0 % volume, 0.1% increments

Volume: 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

• Hydrogen Sulfi de ( H

S): 0 - 100 ppm, 1 ppm increments

ESM-01 Toxic

• Ammonia (NH3): 0 - 75.0 ppm, 0.1 ppm increments

• Arsine (AsH3): 0 - 1.50 ppm, 0.01 ppm increments

• Chlorine (Cl

): 0 - 3.00 ppm, 0.01 ppm increments

• Chlorine (Cl2): 0 - 10.0 ppm, 0.1 ppm increments

• Hydrogen Cyanide (HCN): 0 - 15.0 ppm, 0.1 ppm increments

• Phosphine (PH

): 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)

Combustible Gas (%LEL): 10 %LEL/50 %LEL Combustible Gas (%Volume): 100 %/100 % CO2 0 - 5,000 ppm: 2,500 ppm/5,000 ppm CO2 0 - 5.00%: 0.50 %/3.0 0 % CO2 0 - 50.0%: 50.0%/50.0% CO2 0 - 100%: 100%/100% Oxygen: 19.5%(decreasing)/23.5% (i ncreasing) Carbon Monoxide: 25 ppm/50 ppm Hydrogen Sulfide: 10 ppm/50 ppm Ammonia: 12 ppm/25 ppm Arsine: 0.20 ppm/0.50ppm Chlorine (0 - 3.00 ppm): 0.50 ppm/1.50 ppm Chlorine (0 - 10.0 ppm): 1.0 ppm/3.0 ppm Hydrogen Cyanide: 5.0 ppm/10.0 ppm Phosphine: 0.10 ppm/0.30 ppm Sulphur Dioxide: 1.00 ppm/2.00 ppm

Construction (ho usi n g) Explosion-pro of Ju n cti on Bo x, NE MA 4X Area Classification Explosion-proof for Class I, Groups B, C, and D (Combustible, CO

H2S, and CSA Type oxygen)

Sampling Method Diffusion

, CSA Type CO and

M2A Transmitter Operator’s Manual 2

Table 1: M2A Specifications

Input Power 10 - 30 VDC Controls • Three push butto n sw it ch e s

• 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 LEL -40°C to 75°C N/A Oxygen -20°C to 45°C -20°C to 50° C H

S -40°C to 40°C -40°C to 50° C

Operating Temperature

CO -5°C to 40°C -20°C to 50°C Toxic (ESM-01) N/A -10°C to 40°C Infrared LEL -20°C to 50°C -40°C to 50° C Infrared CO

Accuracy Catalytic Combustible Gas

-20°C to 50°C -40°C to 50° C

: ± 5% of reading or ± 2% LEL (whichever is greater) IR Combustible Gas/IR CO2:

± 5% of reading or ± 2% of full scale (whichever is greater) Oxygen

± 0.5% O

Hydrogen Sulfide: ± 5% of reading or ± 2 ppm H

S (whichever is greater)

Carbon Monoxid e : ± 5% of reading or ± 5 ppm CO (wh ichever is greate r) ESM-01 Toxic Sensors

± 10% of reading or ± 5% of ful l scale (whichever is greater)

These are the RKI factory settings. You can change the alarm settings in Configuration Mode. See

“Viewing & Changing M2A Paramete rs” on page 31.

WARNING: When using the M2A, you must follow the instructions and warnings in this

manual to assure proper and safe operation of t he M2A and to minimize the risk of personal injury. Be sure to maintain and periodically calibrate the M2A as described in this manual.

3 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.

3/4 NPTConduit Hub, P lugged

Junction Box Cover

Mounting Slot (2x)

Magnetic

Wand

Window

3/4 NPT Conduit Hub

Detector

(Cat alytic LEL Detector Shown)

Figure 1: M2A Ex ternal 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 in. conduit hubs to mount the detector to the junction box (factory installed in the bottom hub) and connect wiring from an external device (left h ub). T he top hub i s shipp ed with a factory i nstalle d and sealed co nduit 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 hu b 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.

M2A Transmitter Operator’s Manual 4

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.

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” cond uit hu b on the r ight bo ttom si de of the M2A. A variety of detectors may be used with the M2A. Table 2 below lists the detectors that can be used with the M2A.

Table 2: M2A Detectors

Target Gas, Range Detector(s) Used

Combustible Gas, 0 - 100% LEL • 61-0140RK (Catalytic UL version)

• 61-0140RK-05 (Catalytic CSA version)

Hydrogen, 0 - 100% LE L • NC-6205-01 (Catalytic UL version, hyd rogen specific)

• NC-6205-05 (Catalytic CSA version, hyd r ogen specific)

, 0 - 100% LEL • 61-0190RK-CH 4 ( IR UL)

HC, 0 - 100% LEL (cal. to propane) • 61-0190RK-HC (IR UL) CH

, 0 - 100% volume • 61-0192RK- C H4 ( IR UL)

, 0 - 5,000 ppm • 61-0191RK-02 (IR UL)

CO2, 0 - 5% • 61-0191RK -03 (IR U L)

, 0 - 50% • 61-0191RK-05 (IR UL)

, 0 - 100% • 61-0191RK -10 (IR UL)

Oxygen, 0 - 25% • 65-2494RK (capil lary)

CO, 0 - 300 ppm • 65-2433RK-05 (CSA)

• 61-0198RK-02 (IR)

• 61-0198RK-03 (IR)

• 61-0198RK-05 (IR)

• 61-0198RK-10 (IR)

• 65-2510RK (partial pressure)

• 65-2511 RK (capilla ry )

• 65-2514RK (capillary, CSA)

• 65-2496RK

S, 0 - 100 ppm • 65-2423RK-05 (C SA)

NH3, 0 - 75 ppm • 65-2300RK- NH3

AsH

, 0 - 1.5 ppm • 65-2300RK-ASH3

5 M2A Transmitter Operator’ s Manual

• 65-2495RK

Table 2: M2A Detectors

Target Gas, Range Detector(s) Used

Cl2, 0 - 3 ppm • 65-2300RK-CL2

, 0 - 10 ppm • 65-2300RK-CL- 10

, 0 - 1 ppm • 65-2300RK-PH3

, 0 - 6 ppm • 65-2300RK-SO2

Catalytic LEL Detectors

The catalytic LEL detectors have a 1/2” NPT thread and require a 3/4”NPT x 1/2”NPT reducer to install in the detector hub. The rest of the detectors have a 3/4” NPT mounting thread and are installed directly in the detector hub.

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.

Oxygen Detectors

There are four types of oxygen detectors available, a non-explosion proof partial pressure type, a non-explosion proof capillary 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 p r essure type. The CSA type oxygen detector (65-2514RK) and one of the non-explosion proof capillary type detectors (65-2494RK) have a replaceable plug-in sensor ins ide the detector ho using while the entire oxygen detector must be removed if replacement is required for the other two.

Detector Housing Body

Cap Gasket

Oxygen Sensor

Detector Housing Cap

Flame Arrestor Guard

Figure 2: 65-2514RK Oxygen D etector, CSA

M2A Transmitter Operator’s Manual 6

Detector Housing Body

Cap Gasket

Plug-In Oxygen Sensor

Detector Housing Cap

Hydr ophobic Membran

Figure 3: 65-2494RK Oxygen Detector, Non-Explosion Proof, Capillary Type

CO and H

Both types of CO and H

S Detectors

S detectors have replaceable plug-in sensors inside the detector housing.

The CO detector includes 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 H

S and certain hydrocarbons. The 65- 2423RK- 05 explo sion-p roof H2S detector includes a rubber

boot and a spacer which help ensur e that the sensor remains plugged into th e detector housing body. The 65-2495RK non-explosion-proof H

S detector includes an adhesive backed gasket inside the

detector housing cap which helps ensure that the sensor remains plugged into the detector housing body.

Detector Housing Body

Cap Gasket

Plug-In CO Sensor

Rubber Boot W ith Charcoal F ilter

Detector Housing Cap

Flame Arresto Guard

Figure 4: 65-2433RK-05 CO Detector, CSA

7 M2A Transmitter Operator’ s Manual

Detector HousingBody

Cap Gasket

CO Plug-in Sensor

Charcoal Filter w/Rubber Boot

Detector Housing Cap

Hydrophobic Membrane

Figure 5: 65-2496RK CO Detector Non-Explosion Proof

Detecto r Housing B ody

Cap Gasket

H2S Plug-in Sensor

Spacer

Rubber Boot

Detector Housing Cap

Flame Arrestor Guard

Figure 6: 65-2423RK-05 H

S Detector, CSA

M2A Transmitter Operator’s Manual 8

Detector Housing Body

Cap Gasket

H2S Plug-in Sensor

Figure 7: 65-2495RK H2S Detector Non-Explosion Proof

Detector Housing Cap

Hydrophobic Membrane

ESM-01 Detectors

The constr uction 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 Cl

detector cannot be used with an NH3 detector. 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.

Detector Housing Body (different for each detector type)

Cap Gasket

Sensor (different for each detector type)

Detector Housing Cap

Splash Guard (removable)

Figure 8: ESM-01 Type Detector

9 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.

3/4" NPT ConduitOpening, Plugged

Power/Signal

TerminalStrip

Detector Terminal Strip

(Comb/CO2 Version Shown)

Detector Current

Adjust Pot

(Comb/CO2 Type Only,

FactoryAdjust)

3/4" NPT

Conduit

Opening

fo r Wi r e

Entry

Ground Jumper

Programming

Connector

(Factory Use)

ModbusTerminal Strip

TerminationJumper

RibbonCableConnector

Fail LED

Alarm 1 LED

Alarm2 LED

RX LE D

TX LED

Relay Terminal Strips

Junctio n Box

TerminalPCB

Control PCB

Magnetic Switches

ENTER

DOWN/NO

- S +

LEL

R W G B

RS 485 PWR/SIG

A B C

FAIL

C NC NO

ALARM 1

C NC NO

ALARM 2

C NC NO

UP/YES

RKI INSTRUMENTS

M2AT RANSMITTER

Push Button

Switches

Cont rol

UP/YES

DOWN/NO

ENTER

OLED Display

View WithCover and

Control PCB Removed

View With Cover Removed

Figure 9: M2A Internal Components

Terminal PCB

The terminal PCB is encapsulated in epoxy for protection against moistur e and physi cal 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 wh i ch 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 relays.

Two columns of plug-in style terminal strips ar e 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 ribbo n cable. A 5 position connector on the left side of the terminal PCB is used by factory or field service pers on nel

M2A Transmitter Operator’s Manual 10

to program the M2A. On the combustible and CO2 versions of the M2A, a factory adjust pot just above the programming connector is used to set the detector current.

Power/Sign al 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 ter minal strip in the left terminal column. For a combustible or CO

M2A, all four terminals are used to

connect the detector to the M2A. For a toxic o r 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).

Comb/CO2

Detector

Terminal

Strip

Toxic/Oxy

Detector

Terminal

- S +

LEL

R W G B

RS 485 PWR/SIG

A B C

C NC NO

FAIL

ALARM 1

ALARM 2

Strip

- S +

LEL

R W G B

RS 485 PWR/SIG

A B C

C NC NO

FAIL

ALARM 1

ALARM 2

Figure 10: Detector Terminal Strip

NOTE: The detector is factory-wired to the M2A. See “Wiring the M2A Transmitter ” on

page 18 for all wiring procedures related to M2A.

Modbus Terminal Str ip

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.

11 M2A Trans mitte r Op erato r’ s Manu al

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 51 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 51 for a description of using the M2A in a Modbus system.

Control PCB

The OLED display and control switches are located o n 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.

OLED Display

The OLED display is located at the top of the control PCB. It indicates the current gas reading and displays messages and parameters in the M2A’s programs.

Control Buttons

The M2A includes three push button switches that allow you to enter the M2A’s operating modes, navigate through the modes, update settings, and save changes to the settings. The push button switches are located along the bottom edge of the control PCB (see Figure 9). The UP/YES button is on the left, the DOWN/NO button is in the middle, and the ENTER button is on the right.

Tabl e 3: M2A Control Button Functions

Switch Function

UP (YES) • Saves settings

• Changes the displayed setting

• Enters the Calibration Program

• Enters Gas Type Mode (press with DOWN/NO button)

• Enters Configuration Mode (press with ENTER button)

DOWN (NO) • Cancels setting changes

• Changes the displayed setting

• Enters Gas Type Mode (press with UP/YES button)

• Enters Modbus Mode (press wi th ENTER button)

• Displays the Information Screen

ENTER • Initiates operations

• Enters Configuration Mode (press with UP /YES button)

• Enters Modbus Mode (press with DOWN/NO button)

• Functions as an alarm reset switch

Just above each push button switch is a magnetic switch with the same function as the push button

M2A Transmitter Operator’s Manual 12

switch below it. The magnetic switches are for use in non-intrusive calibration. They are actuated by bringing the magnetic wand close enough to them to actuate them. Although the magnetic switches have the same functions as the push button switches, it is not practical to use them for operations other than calibration because it is not possible to actuate two magnetic switches at once with only one magnetic wa nd. Si nce disp layi ng the I nformat ion Scr een onl y requir es th e use o f one switch, the wand may be used to show the Information Screen (see “Information Screen” on page 26).

Status LEDs

The M2A includes five status LEDs that are located above the display (see Figure 9).

• Fail LED The fail LED turns on when the M2A is experiencing a fail condition. A fail condition can be

caused by a detector failure or low detector signal.

• Alarm 1 LED The alarm 1 LED is on when the M2A is experiencing an alarm 1 condition.

• Alarm 2 LED The alarm 2 LED is on when the M2A is experiencing an alarm 2 condition.

• RX & TX LED’s These LED’s indicate data being received (RX) and transmitted (TX) when the M2A’ s Modbus

output is operating.

13 M2A Trans mitte r Op erato r’ s Manu al

Chapter 3: Installation & Startup

Overview

This chapter describes procedures to mount the M2A Transmitter in the monitoring environment and wire it to input power and devices.

Mounting the M2A Transmitter

1. Select a mounting site that is representative of the monitoring environment. Consider the following when you select the mounting site.

• Select a site where the M2A is not likely to be bumped or disturbed. Make sure there is

sufficient room to perform start-up, maintenance, and calibration procedures.

• Select a site where the target gas is likely to be found fi rst. For lighter gases, mount the

detector near the ceiling; for heavier gases, mount the detector near the floor.

2. At the monitoring site, use #10 screws throu gh the junction box’ s two mou nting holes to secure the junction box to a vertical surface. Figure 11 - Figure 16 show the outline and mounting dimensions for each version of the M2A. Mount the M2A with the detector facing down as shown in the following figures.

4.59

2.41

5.00

3/4 NPT Conduit Hub

5.86

1 1/2-2 0 For Calibration Cup

1.02

Figure 11: Outline & Mounting Dimensions, Catalytic LEL

M2A Transmitter Operator’s Manual 14

5.23

7.7 max

2.3 max

.47 (2 X)

.30 (2 X)

5.86

4.59

1.02

5.23

.47 (2 X)

.30 (2X)

2.41

5.00

3/4 NP T Conduit Hub

7.4 max

1.9 max

5.86

Figure 12: Outline & Mounting Dimensions, IR Combustible & CO

4.59

5.23

1 1/2- 20 F or Calibration Cup

2.41

.47 (2X)

5.00

3/4 NP T Conduit Hub

7.9 m a x

2.6 m a x

1.02

.30 (2X)

Figure 13: Outline & Mounting Dimensions, Oxygen, Partial Pressure Type

15 M2A Trans mitte r Op erato r’ s Manu al

5.86

4.59

2.41

5.00

3/4 NPT Conduit Hub

5.23

1.02

1 1/2-20 For CalibrationCup

.4 7 (2 X)

1.5 max

.3 0 (2 X)

Figure 14: Outline & Mounting Dimensio ns, Replaceable Sensor, Non Explosion Proof,

S, CO, and Oxygen

6.5 max

5.86

4.59

1.02

5.23

.47 (2X)

.30 (2X)

2.41

5.00

3/4 NPT Conduit Hub

8.4 max

3.2 max

Figure 15: Outline & Mounting Dimensions, CSA Type H

M2A Transmitter Operator’s Manual 16

S, CO, and Oxygen

5.86

4.59

5.23

.47 (2X)

.30 (2X)

2.41

5.00

3/4 NPT Conduit Hub

10.4 max

4.82 max

1.02

Figure 16: Outline & Mounting Dimensions, ESM-01 Toxic

17 M2A Trans mitte r Op erato r’ s Manu al

Wiring the M2A Transmitter

WARNING: Always verify that the power source is OFF before making any wiring

connections.

1. Remove th e junction bo x cover.

2. Grasp the control PCB by its edges.

3. Gently pull until the control PCB is pulled away from the banana jacks. Take care not to pull too hard and damage the cable which connects the control and terminal PCBs.

4. Let the control PCB hang by the cable. The terminal strips are now visible on the terminal PCB. The control PCB may be left hanging while wiring is done. If desired, the control PCB may be disconnected from the cable and set aside while wiring.

5. The detector leads are factory wired. Verify that the detector leads are wired to the detector terminal strip as shown in the applicable figure below:

• C ata lytic LEL/Co mbustible IR/CO

Detectors

The wiring for these types of detectors is the same. Red wire to terminal labeled LEL R, white wire to terminal labeled LEL W , g reen wire to terminal labeled LEL G, black wire to terminal labeled LEL B.

Black

White

Red

Green

- S +

LEL

R W G B

RS 485 PWR/SIG

A B C

FAIL

C NC NO

ALARM 1

C NC NO

ALARM 2

C NC NO

Figure 17: Catalytic LEL Detector Wiring

Black

Green

White

Red

- S +

FAIL

C NC NO

ALA R M 1

C NC NO

ALARM 2

C NC NO

Figure 18: Combusti bl e IR/ CO

LEL

R W G B

RS 485 PWR/SIG

A B C

Detector Wiring

M2A Transmitter Operator’s Manual 18

• Oxygen Detector, Partial Pressure, Capillary Type, and CSA Capillary Type

The wiring for all the oxygen detectors is the same. White wire to terminal labeled OXY +, green wire to terminal labeled OXY -.

Green

White

Figure 19: Partial Pressure Oxygen Detector Wiring

Green

White

- S +

PWR/SIG

TOXIC OXY

+ - + -

RS 485

A B C

- S +

PWR/SIG

TOXIC OXY

+ - + -

RS 485

A B C

FAIL

C NC NO

ALARM 1

C NC NO

ALARM 2

C NC NO

FAIL

C NC NO

ALARM 1

C NC NO

ALARM 2

C NC NO

Figure 20: Capillary Oxygen Detector Wiring

FAIL

C NC NO

ALARM 1

C NC NO

ALARM 2

C NC NO

Green

White

- S +

PWR/SIG

TOXIC OXY

+ - + -

RS 485

A B C

Figure 21: CSA Capillary Type Oxygen Detector Wiring

19 M2A Trans mitte r Op erato r’ s Manu al

Green

White

- S +

PWR/SIG

TOXIC OXY

+ - + -

RS 485

A B C

Figure 22: Capillary Type Replaceable Sensor Oxygen Detector Wiring

• CSA type CO or H

S gas detector.

Red wire to terminal labeled TOXIC +, black wire to terminal labeled TOXIC -.

- S +

PWR/SIG

Black

Red

TOXIC OXY

+ - + -

RS 485

A B C

C NC NO

FAIL

ALARM 1

ALARM 2

FAIL

C NC NO

ALA R M 1

C NC NO

ALARM 2

C NC NO

Figure 23: H

S/CO Detector Wiring, CSA

• Non Explosion Proof CO or H2S gas detector

Red wire to terminal labeled TOXIC +, black wire to terminal labeled TOXIC -.

- S +

PWR/SIG

Black

Red

Figure 24: H

S/CO Detector Wiring

TOXIC OXY

+ - + -

RS 485

A B C

M2A Transmitter Operator’s Manual 20

FAIL

C NC NO

ALARM 1

C NC NO

ALARM 2

C NC NO

• ESM-01 Toxic Detectors

The ESM-01 toxic detectors have one black wire and one color coded wire. Connect the color coded wire (see chart below) to the terminal labeled TOXIC + and the black wire to the terminal labeled TOXIC -.

Black

See Chart

Wire Color GasType Brown AsH3 Yellow Cl2

NH3Red Orange NO Green PH3 Blue SO2

Figure 25: ESM-01 Toxi c Detector Wiring

- S +

PWR/SIG

TOXIC OXY

+ - + -

RS 485

A B C

FAIL

C NC NO

ALARM 1

C NC NO

ALARM 2

C NC NO

6. To gain access to a plug-in terminal strip for wiring, pull it out of its socket by grasping the wall between two terminal positions with needle nose pliers and pulling. Be careful not to exert too much force on the wall to avoid damage to the terminal strip. The detector terminal strip and the alarm 1 relay terminal strip may be removed by grasp in g them with yo ur fi nger s if th e adjacent terminal strips have been removed.

W ARNING: If the M2A is installed in a hazardous location, use appropriately rated conduit,

conduit fittings, and appropriate construction technique that complies with the local electrical code. In addition, use appropriately rated conduit, conduit fittings, and appropriate construction technique to maintain the NEMA 4X environmental ratin g of the junction box and avoid water entering the junction box at the conduit hubs.

7. Guide multi conductor shielded cable or cables or wires in conduit through the conduit hub on the left side of the junction box.

WARNING: If the top conduit hu b is used for wiring, be sure to seal the threads to ensure

water does not enter the junction box. A conduit seal, which is normally required to maintain the junction box’ s hazardous location rating, will also help to prevent water from entering through the top port.

21 M2A Trans mitte r Op erato r’ s Manu al

The number of cables or wires needed will depend on whether the M2A is wired to a gas monitoring controller or just to power, whether any relays are used, and whether the Modbus output is used.

NOTE: If the M2A is being wired to a PLC or DCS device, see “Appendix B: PLC and DCS

Device Wiring” on page 66, then continue with step 8.

Use the following recommendations to determine how to wire the M2A:

• If Modbus connections will not be used and only the PWR/SIG connections will be used,

use a two or three conductor shielded cable or two or three wires in conduit for connections to the power/signal terminal strip depending on whether or not the signal (S) terminal is used. The S terminal has a 4 - 20 mA output, but if you do not need to monitor this signal and do not connect to the S terminal to access this signal, the M2A will still function completely.

Table 4: Wire Size for PWR/SIG Connections

Max Distance to Controller

w/18 Gauge Wire

2,500 ft. 5,000 ft. 8,000 ft.

Max Distance to Controller w/

16 Gauge Wire

Max Distance to Controller

• If the PWR/S IG connection s and one or more relays are used, route the connections to the

M2A in conduit. Use shielded cable in the conduit for the PWR/SIG connections and unshielded cable or individual wires for the relay connections. Make sure any wire or cable used for relay wiring is appropriately rated for the power that it will carry.

NOTE: If shielded cable is used for the PWR/SIG connections, leave the cable shield’s drain

wire insulated and disconnected at the M2A. You will connect the opposite end of the cable’s drain wire at the controller or device.

• If the M2A will be wired into a Modbus network, see “Chapter 8: RS-485 Modbus

Output” on page 51.

w/14 Gauge Wire

M2A Transmitter Operator’s Manual 22

RKI Controller

Terminals

See Figure 26 below for field wiring connections to the M2A.

Ala rm De vice

Power

(24 VDC) +

4 - 20 mA In (S)

(24 VDC) -

Fail Alarm Device

FAIL

C NC NO

Alarm 1 Ala rm De vice

ALARM 1

C NC NO

Alarm 2 Ala rm De vice

ALARM 2

C NC NO

Typical Alarm Wiring Shown

See

Detector

Wiring

See

Modbus

Wiring

- S +

LEL

R W G B

RS 485 PWR/SI G

A B C

Figure 26: Wiring the M2A to a Controller and Alarm Devices

8. Re-install the control PCB (and ribbon cable if necessary). Be sure the ribbon cable is routed down below the control PCB so it will not be damaged by the cover when it is screwed back on.

9. Secure the junction box cover to the junction box.

Start Up

10. Make controller, device, and relay connections as appropriate. If shielded cable is used for the PWR/SIG connections, connect the cable shield’s drain wire to an available chassis ground at the gas monitoring controller, recording device, or programmable controller .

Introducing Incoming Power

1. Complete the installation procedures described earlier in this m anual.

2. Verify that all wiring connections are correct and secure.

3. Turn on the incoming power.

4. If necessary, turn on the controller or other monito ri ng device th at is connected to the M2A.

5. The OLED display will indicate the firmware version when the M2A is first powered up and will then count down a one minute warm-up period before normal operation begins. During normal operation, the display will indicate the target gas and current gas reading. Verify that the display is indicating the target gas and current gas reading after the warm-up period is complete and normal operation begins.

METHANE

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23 M2A Trans mitte r Op erato r’ s Manu al

NOTE: Allow the M2A’ s detector to warm up for 15 minutes bef ore you cont inue with t he next

section, “Adjusting the Fresh Air Reading.”

Adjusting the Fresh Air Reading

When the M2A is shipped from RKI Instruments, Inc., it is factory calibrated. If a full calibration is desired at startup, see “Calibration, Combustible Gas, CO2, and Toxic Versions” on page 42 or “Calibration, Oxygen Version” on page 45.

Verify that the M2A is in a fresh air environment (environment known to be free of the target gas and combustible or toxic gas vapors and of normal oxygen content, 20.9%).

CAUTION: If you suspect the presence of combustible gas, CO2, toxic gas, or that the oxygen

content is not normal in the monitoring environment, use the calibration kit and the zero air calibration cylinder to introduce “fresh air” to the detector and verify an accurate fresh air setting. See the “Calibratio n, Combus tible Gas , C O2, and Toxic Versions” on page 42 or “Calibration, Oxygen Version” on page 45 for instructions on how to use a zero air cylinder when performing a fresh air adjustment.

Non-Intrusive Fresh Air Signal Adjustment

If the M2A is installed in a classified area and non-intrusive zero adjustment is requi red, fol low the instructions below, but do not remove the junction box cover. Use the magnetic wand accessory to actuate the magnetic switches instead of pushing the control switch buttons. To actuate a magnetic switch and perform the same operation as pressing a control switch button, touch the magnet in the end of the magnetic wand to the M2A’s glass cover directly over the magnetic switch you wish to actuate. Touching the glass and removing the wand is the same as pressing and releasing a button. Touching the glass and keeping the wand in place is the same as pressing and holding a button.

W ARNING: The M2A is not an active gas monitoring device during the fresh air adjustment

procedure. The 4-20 mA output signal will “freeze” at 3.5 mA for a toxic, combustible gas, or CO

M2A, or at 17.4 mA for an oxygen M2A, and all r el ays

will remain in their non-alarm state while the M2A is in Calibration Mode. The output signal will not indicate current rea dings and the relays will not resume operating normally until the M2A is in norma l operation again.

NOTE: While in the calibration program, if there is no switch activity for the calibration time-

out period the unit will return to normal operation. The factory set time-out is 15 minutes. If you want a different time-out period , see “Viewing & Changing M2A Parameters” on page 31 for instructions to change the calibration time-out.

Combustible Gas, CO

, and Toxic Versio ns, Adjus ting the F resh Air Readin g

1. While in normal operation, press and hold the UP/YES button for 5 seconds to enter Calibration Mode. Release the button when the following screen appears.

Calib? YES/NO

M2A Transmitter Operator’s Manual 24

2. Press and release the UP/YES button to continue. The display will indicate the target gas and CAL Mode for a few seconds before showing FreshAir Adjust?.

3. Press and release the UP/YES button. ENTER will alternate with FreshAir on the top display line and the current gas reading will be on the bottom display line.

4. Press and release the ENTER button. The M2A will perform a zero operation and the display will indicate SPAN w/Cal Gas?.

5. Press and release the DOWN/NO button. The display will indicate Leaving CAL Mode and the M2A will return to normal operation.

Oxygen Version, Adjusting the Fresh Air Reading

1. While in normal operation, press and hold the UP/YES button for 5 seconds to enter Calibration Mode. Release the button when the following screen appears.

Calib? YES/NO

2. Press and release the UP/YES button to continue. The display will indicate OXYGEN CAL Mode for a few seconds before showing FreshAir Adjust?.

3. Press and release the UP/YES button. ENTER will alternate with FreshAir on the top display line and the current oxygen reading will be on the bottom display line.

4. Press and release the ENTER button. The M2A will perform a span operation and then the display will indicate ZERO w/Cal Gas?.

5. Press and release the DOWN/NO button. The display will indicate Leaving CAL Mode and the M2A will return to normal operation.

25 M2A Trans mitte r Op erato r’ s Manu al

Chapter 4: Operation

Overview

This chapter describes the M2A in normal operation. This chapter also describes the M2A in alarm 1, alarm 2, and fail conditions and suggests responses to these conditions.

Normal Operation

Normal operation is defined as follows:

• The start-up procedure is complete.

• The M2A is not indicating an alarm 1, alarm 2, or fail condition.

• The M2A is not in Calibration, Configuration, or Gas Type modes.

During normal operation, the M2A simultaneously displays the current gas reading, unit of measure, and target gas. The example below illustra tes a typical combustible gas M2A.

Information Screen

The Information Screen displays the M2A’s operating voltage and firmware and hardware information. To display the Information Screen, do the following:

1. Press and hold the DOWN/NO button for 3 seconds. The Information Screen will appear.

2. Continue holding the DOWN/NO button to keep the Information Screen on the display. The top line indicates the operating voltage that is connected to the M2A. The second line indicates the firmware that is running, version 6.0 in this example, and the M2A’s hardware version, version 2A in this example. This information may be useful if you need to contact the factory with questions about the M2A.

3. Release the DOWN/NO button when you are done viewing the Information Screen. The display will return to the normal operation screen within a couple of seconds.

METHANE

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24.2V v6.0L 2A

M2A Transmitter Operator’s Manual 26

4 - 20 mA Signal Output Operation

The output at the S terminal of the power/signal terminal strip is a 4 - 20 mA signal that corresponds to the detection range of the M2A. During normal operation, this signal tracks the gas concentration on the OLED display.

There are several circumstances where the signal output will not track the di splay reading but will behave as follows:

• When the M2A is in its warm-up period, the signal output will be fixed at 3.5 mA (zero) for all gas types except oxygen. For oxygen types, the output will be fixed at 17.4 mA (20.9% oxygen) while the M2A is in warm-up.

• When the M2A’s gas type is changed, the M2A will enter Configuration Mode for you to verify the parameter settings. When you exit Configuration Mode, the display will indicate NEEDS CALIBRATION and will continue to indicate this until Calibration Mode is entered and a calibration is performed. In this situation, the signal output will be fixed at 3.5 mA for LEL and toxic versions and 17.4 mA for oxygen versions from the time Gas Type Mode is entered until the M2A is calibrated and returns to normal operation.

• If you enter Calibration Mode, Configuration Mode, Gas Type Mode, or Modbus Mode, the signal output will be fixed at 3.5 mA for combustible gas, CO

mA for oxygen versions until the M2A returns to normal operation.

, and toxic versions and 17.4

• If the M2A’s input power decreases below 9.5 volts so that the M2A is in a low power alarm, the signal output is fixed below 2.4 mA until the low power alarm is cleared.

• If the M2 goes into a fail condition, after a 30 second delay, the signal output is fixed below 2.4 mA until the fail alarm is cleared. During the 30 second delay, the signal output follows the detector output. In the case of a downscale reading, the display and the signal output continue to track the reading down to -99% of full scale (1.15 mA).

27 M2A Trans mitte r Op erato r’ s Manu al

Alarm Indications

NOTE: The M2A includes alarm on and alarm off delay settings for alarm 1 and alarm 2. The

Condition Cause Visual Indication(s)

alarm indications described in this section operate according to the factory set alarm settings. See Table 6 on page 32 for all the factory settings.

Table 5: Visual and Audible Alarm Indications

Alarm 1

Alarm 2

Fail • Disconnect ed or misconnected detector

Low Power DC power source less than 9.5 volts. • F LED is on

If the M2A is in both an alarm 1 and an alarm 2 conditio n, bo th ala rm LEDs are on an d the

display alternates between the gas reading and the ALMS 1&2 message.

Increasing (decreasing for O2) gas reading at or above the alarm 1 setpoint

Increasing gas reading at or above the alarm 2 setpoint

wiring

• Display reading at -10% of full scale or lower

• Defective components

• A1 LED is on

• Gas reading alternates with

ALARM-1 message

• A2 LED is on

• Gas reading alternates with

ALARM-2 message

• F LED is on

• FAIL message replaces gas

reading

NOTE: There is a 30 second delay on the fail condition.

• LowPower message and actual

voltage of incoming DC power

NOTE: You can select normally energized (N. EN) or normally de-energized (N. DE-EN)

alarm 1 and alarm 2 relay settings in Configuration Mode. The following sections describe the standard factory setting for these relays which is N. DE-EN.

The fail relay is factory set as N. EN and is not user-adjustable.

Alarm 1 Condition

Alarm 1 Condition Indications

When the gas reading reaches the alarm 1 setpoint, the M2A senses an alarm 1 condition. The M2A alerts you to an alarm 1 condition as follows:

• The A1 LED turns on.

• The gas reading alternates with the ALARM-1 message .

• The alarm 1 relay energizes.

Responding to an Alarm 1 Condition

1. Follow your established procedure for a low level combustible or toxic gas condition or a decreasing oxygen concentration condition.

2. After the gas reading falls below (above for oxygen) the alarm 1 setpoint, press the ENTER button to reset the alarm 1 circuit. Resetting the alarm 1 circuit turns off the A1 LED, resets the

M2A Transmitter Operator’s Manual 28

OLED display, and de-energizes the alarm 1 relay.

NOTE: If the ENTER button is pressed while the M2A is in an alarm 1 condition, the A1 LED

will flash but all other indications will remain unchanged.

You cannot de-energize the alarm 1 relay until the gas reading falls below (above for oxygen) the alarm 1 setpoint.

Alarm 2 Condition

Alarm 2 Condition Indications

When the gas reading reaches the alarm 2 setpoint, the M2A senses an alarm 2 condition. The M2A alerts you to an alarm 2 condition as follows:

• The A2 LED turns on.

• The gas reading alternates with the ALARM-2 message .

• The alarm 2 relay energizes.

NOTE: If the M2A is in both an alarm 1 and alarm 2 condition, both the A1 and A2 LEDs will

be on, the gas reading will alternate with the ALMS 1&2 message, and both alarm relays will energize.

Responding to an Alarm 2 Condition

1. Follow your established procedure for a high level combustible or toxic gas condition or an increasing oxygen concentration condition.

2. After the gas reading falls below the alarm 2 setpoint, press the ENTER button to reset the alarm circuit. Resetting the alarm circuit turns off the A2 light, resets the OLED display, and de-energizes the alarm 2 relay.

NOTE: If the ENTER button is pressed while the M2A is in an alarm 2 condition, the A2 LED

will flash but all other indications will remain unchanged.

You cannot de-energize the alarm 2 relay until the gas reading falls below the alarm 2 setpoint.

Fail Condition

Fail Condition Indications

The M2A indicates a fail condition for any of the following:

• The detector wiring is disconnected or incorrectly connected.

• The display reading is -10% of full scale or lower.

When the M2A senses a fail condition, it alerts you as follows:

• The F LED turns on.

• The gas reading is replaced by the FAIL message.

• The fail relay de-energizes.

NOTE: The fail alarm has a 30 second delay.

29 M2A Trans mitte r Op erato r’ s Manu al

Responding to a Fail Condition

1. Verify that the detector wiring is correctly and securely connected.

2. If the M2A has a replaceable plug-in sensor, verify that the replaceable plug-in sensor in the detector housing is properly installed.

Low Power Alarm

Low Power Alarm Indications

The M2A senses a low power condition when the DC power source is 9.5 volts or less.

WARNING : While in a low power condition, the M2A is not an active gas monitor.

When the M2A senses a low power condition, it alerts you as follows:

• The F LED turns on.

• Th e message LowPower is indicated on the top line of the OLED display and the input voltage is displayed on the bottom line of the OLED display.

• The fail relay de-energizes.

NOTE: The low power alarm cannot be cleared using the ENTER button.

When the voltage increases to 10.0 volts, the low power alarm is cleared and the M2A will begin its warm-up sequence.

Responding to a Low Power Condition

1. Determine and correct the cause of the low power condition.

2. When the input power increases above 10.0 volts, the M2A will begin its warm-up sequence.

3. Verify that the M2A enters normal operation after its warm-up sequence. If necessary , perform a fresh air adjustment. See “Adjusting the Fresh Air Reading” on page 24.

M2A Transmitter Operator’s Manual 30

Chapter 5: Configuration Mode

Overview

This chapter describes how to view and change M2A parameters using Configuration Mode. It is accessed using the program buttons.

Configuration Mode incl udes a 5-mi nute time-o ut featur e. If you do not press a cont rol but ton for 5 minutes, the M2A automatically returns to normal operation.

NOTE: If the M2A returns to normal operation because of a time-out, it enters a warm-up

period just as it does when it is first turned on.

If you are installing a new M2A, it has been setup at the factory. Use Configuration Mode only if you want to change the M2A’s setup. If you want to change the detector type see “Chapter 6: Gas Type Mode” on page 34.

Viewing & Changing M2A Parameters

1. While in normal op eration, simultaneou sly pr ess and h old the UP/ YES and EN TER button s for 5 seconds to enter Configuration Mode. Release the buttons when the following screen appears.

Enter

Config?

2. If you want to exit Configuration Mode, press and release the DOWN/NO button and the M2A will return to normal operation.

If you want to continue in Configuration Mode, press and release the UP/YES button. The target gas and the full scale will be displayed for a few seconds before the first adjustable parameter, the alarm 1 setpoint, is displayed.

3. If you want to change the currently displayed parameter, use the UP/YES and DOWN/NO buttons to adjust it to the desired setting, then press ENTER to continue to the next parameter.

If the currently displayed parameter is OK, press the ENTER button to proceed to the next parameter.

Table 6 lists the M2A parameters you can set. Table 6 also lists the factory set value for each parameter.

31 M2A Trans mitte r Op erato r’ s Manu al

Tabl e 6: Configuration Parame ters

Parameter

(Factory Set Value)

ALARM-1 (level) (See “M2A Specifications” on page 2)

ALARM-1 (activation) (Decrease for oxygen M2A, Increase for all other types)

ALARM-1 (relay action) (N. DE-EN)

ALARM-1 (relay reset) (LATCH)

A1 OnDy (alarm 1 on delay) (1 secs)

A1 OffDy (alarm 1 off delay) (0 sec.)

Description

The gas reading at which the M2A initiates an alarm 1 condition.

Indicates if the alarm 1 circuit is activate d by gas readin gs increas ing (Increase) or decreasing (Decrease) to the ALARM-1 Level.

If set as N. DE-EN, the alarm 1 relay is de-energized in normal operation and energizes when an alarm 1 condition is initiated. If set as N. EN, the alarm 1 rel a y is energized in normal operation and de-energizes when an alarm 1 condition is initiated.

If set as LATCH, you must press the ENTER button to reset the alarm 1 circuit after the alarm 1 condition passes. If set as SELF-RST, the M2A automatically resets the alarm 1 circuit after the alarm 1 condition passes.

The amount of time the M2A delays activatio n of the ala rm 1 circuit on ce an alarm 1 condition is initiated. It can be set in 1 second increments from 0 - 60 seconds, in 1 minute increments from 1 - 15 minutes, and in 15 minute increments from 15 - 60 minutes.

The amount of time the M2A delays turning off the alarm 1 circuit once an alarm 1 condition passes. Th is pa ramete r appe ars o nl y if th e ala rm 1 re la y re set se ttin g is set to SELF-RST. It can be set in 1 second increments from 0 - 60 seconds, in 1 minute increments from 1 - 15 minutes, and in 15 minute increments from 15 60 minutes.

ALARM-2 (level) (See “M2A Specifications” on page 2)

ALARM-2 (activation) (Increase for all types)

ALARM-2 (relay action) (N. DE-EN)

ALARM-2 (relay reset) (LATCH)

A2 OnDy (alarm 2 on delay) (1 secs)

A2 OffDy (alarm 2 off delay) (0 sec.)

The gas reading at which the M2A initiates an alarm 2 condition.

Indicates if the alarm 2 circuit is activate d by gas readin gs increas ing (Increase) or decreasing (Decrease) to the ALARM-1 Level.

If set as N. DE-EN, the alarm 2 relay is de-energized in normal operation and energizes when an alarm 2 condition is initiated. If set as N. EN, the alarm 2 rel a y is energized in normal operation and de-energizes when an alarm 2 condition is initiated.

If set as LATCH, you must press the ENTER button to reset the alarm 2 circuit after the alarm 2 condition passes. If set as SELF-RST, the M2A automatically resets the alarm 2 circuit after the alarm 2 condition passes.

The amount of time the M2A delays activatio n of the ala rm 2 circuit on ce an alarm 2 condition is initiated. It can be set in 1 second increments from 0 - 60 seconds, in 1 minute increments from 1 - 15 minutes, and in 15 minute increments from 15 - 60 minutes.

The amount of time the M2A delays turning off the alarm 2 circuit once an alarm 2 condition passes. Th is pa ramete r appe ars o nl y if th e ala rm 2 re la y re set se ttin g is set to SELF-RST. It can be set in 1 second increments from 0 - 60 seconds, in 1 minute increments from 1 - 15 minutes, and in 15 minute increments from 15 60 minutes.

M2A Transmitter Operator’s Manual 32

Table 6: Configuration Parameters (Continued)

Parameter

(Factory Set Value)

ZeroSupp (0.0% of the detection range in terms of the detection units for carbon dioxide channel types, 0.5% oxygen for oxygen types, 2% of the detection range in terms of the detection units for all other types)

FILTER (5 secs)

CAL Time (15 mins)

Auto Zero (Disabled for carbon dioxide channels; Enabled for all other channel types)

4. When you have scrolled through all the adjustable parameters, SA VE IT? YES/NO appears on the display.

Description

The zero suppression feature helps prevent “jumpy” readings near the fresh air reading. For example, if the zero suppression setting for a combustible LEL detector is

2.0% LEL, the M2A will display a reading of 0% LEL for gas readings from 2% LEL to 2% LEL. It is settable from 0 to 6% of the detection range.

The filter feature helps “smooth out” jumpy or noisy signals from the detector. You can set the filter from 0 seconds to 60 seconds in 5 seconds increments. The displayed gas reading is the average reading over the previous time period defined by the filter setting. So if the filter is set to 5 seconds, the displayed gas reading is the average over the past 5 seconds.

The calibration time-out sets the amount of time after the last button push while in Calibration Mode that the M2A will wait before returning to normal operation. If the calib ration t ime-out is set to 15 mins, then M2A will return to normal operation automatically 15 minu tes af ter the last butto n pu sh.

If set to Enabled, the M2A’s firmware will monitor the zero (fresh air) reading and make automatic zero adjustme nts under precisely specified conditions if it determines that a reading change is due to normal sensor drift. If set to Disabled, the Auto Zero function is turned off.

5. If you do not wish to save the adjustments and want to exit Configuration Mode, press and release the DOWN/NO button. The DO OVER? YES/NO message will display. Press and release the DOWN/NO button. The ABORT? YES/NO message will display. Press the UP/ YES button to return to normal operation.

If you wish to change some of the adjustments made, pr ess and release the DOWN/NO button. The DO OVER? YES/NO message will display. Press and release the UP/YES button. The Re-do Config message will display and the M2A will return to the first adjustab le parameter. Go back to step 3 and continue.

If you wish to save t he adjus tments made, pres s and release the UP /YES button . Config Saved is indicated on the display for a few seconds and the M2A returns to normal operation.

33 M2A Trans mitte r Op erato r’ s Manu al

Chapter 6: Gas Type Mode

Overview

This chapter describes how to use Gas Type Mode to select the M2A’s gas type. The gas type determines the target gas and detection range. The combustible gas/CO

have a different terminal PCB and run on different firmware. Your M2A will only have gas type choices available that it can support.

Gas Type Mode includes a 5-minute time-out feature. If you do not press a button for 5 minutes, the M2A automatically returns to normal operation.

NOTE: If the M2A enters normal operation because of a program time-out, it enters a warm-up

period just as it does when it is first turned on.

Selecting the Gas Type

and toxic/oxygen M2As

1. While in normal operation or during the warm-up sequence, press and hold the UP/YES and DOWN/NO buttons for five seconds. Release them when the following screen appears.

Select GasType?

2. If you want to exit Gas Type Mode, press and release the DOWN/NO button. The display will indicate NO CHANGE and the M2A will return to normal operation.

If you want to continue in Gas Type Mode, press and release the UP/YES button. The top display line will indicate GasType? and the bottom display lin e will indicate the target gas choice.

3. Use the UP/YES or DOWN/NO button to scroll through the choices of target gas. Table 7 and Table 8 below list the choices of target gas for the M2A.

Table 7: Combustible Gas/CO2 Gas Types

Gas Type

Choices

HC 0 - 100% LEL iBUT ANE 0 - 100% LEL PROP ANE 0 - 100% LEL HEXANE 0 - 100% LEL

Detection Range

HYDROGEN 0 - 100% LEL METHANE 0 - 100% Volume METHANE 0 - 100% LEL CO2 0 - 5,000 ppm

M2A Transmitter Operator’s Manual 34

Table 7: Combustible Gas/CO

Gas Type

Choices

CO2 0 - 2,000 ppm CO2 0 - 100% volume CO2 0 - 50.0% volume CO2 0 - 5.00% volume NH3 0 - 5.00% volume NH3 0 - 2.00% volume

Table 8: Toxic/Oxygen Gas Types

Gas Type

Choices

H2S 0 - 100 ppm CO 0 - 300 ppm OXYGEN 0 - 25.0% volume

Gas Types

Detection Range

SIH4 0 - 15.0 ppm PH3 0 - 1.00 ppm O3 0 - 1.00 ppm NO 0 - 100 pp m HF 0 - 9.00 ppm HCN 0 - 15.0 ppm HCL 0 - 15.0 ppm H2SE 0 - 5.00 ppm GEH4 0 - 1.50 ppm F2 0 - 3.00 ppm CLO2 0 - 1.00 ppm B2H6 0 - 5.00 ppm ASH3 0 - 1.50 ppm SO2 0 - 6.00 ppm NH3 0 - 200 ppm NH3 0 - 75.0 ppm CL2 0 - 3.00 ppm CL2 0 - 10.0 ppm

35 M2A Trans mitte r Op erato r’ s Manu al

NOTE: Consult factory for availability of detectors for toxic M2A types not listed in “M2A

Specifications” on page 2.

4. When the desired target gas is on the display, press and release the ENTER button. The display will ask SAVE IT? YES/NO.

5. To discard the gas type change, press and release the DOWN/NO button. The display will ask

DO OVER? YES/NO. Press the DOWN/NO button. The display will ask ABORT? YES/ NO. Press the UP/YES button. The M2A will return to normal operation without changing the

gas type. T o save the gas type, p ress and release the UP/YES butto n. The display will indicate Gas Type

Updated, the display will indicate the target gas and the detection range for a few seconds, and then the M2A will enter Configuration Mode automatically so that the parameter settings in Configuration Mode can be verified or changed.

6. While in Configuration Mode press and release the ENTER button to accept the displayed parameter setting and move to the next one. Use the UP/YES and DOWN/NO buttons to adjust a setting. See “Chapter 5: Configuration Mode” on page 31 for a complete description of Configuration Mode.

7. When you have reviewed and accepted the last item in Configuration Mode by pressing the ENTER button, display will ask SA VE IT? YES/NO.

8. To save the configuration settings, press and release the UP/YES button.The display will indicate Config Saved and the M2A will begin its warm-up sequence.

To discard the settings and review them again, press the DOWN/NO button. The display will ask DO OVER? YES/NO. Press the UP/YES button and the display will indicate Re-do Config, then display the target gas and the detection range for a few seconds before returning to Configuration Mode. Repeat steps 6 - 8 until the settings are as desir e d.

9. After the M2A completes its warm-up sequence, the display will indicate CAL NEEDED. Since the gas type has been changed, a successful calibration must be performed before the M2A can enter normal operation.

10. Press and release the UP/YES button to enter Calibration Mode. Normally, you must hold the UP/YES button for 5 seconds to enter Calibration Mode, but since a calibration is required , only a momentary push is needed to enter Calibration Mode after changing the gas type.

11. See “Calibration, Combustible Gas, CO2, and Toxic Versions” on page 42 or “Calibration, Oxygen Version” on page 45 for calibration in structions.

NOTE: When calibrating an M2A after changing the gas type, the M2A will not ask if you want

to calibrate, or whether you want to perform a fresh air adjustment, span adjustment or zero adjustment. Since a complete calibration is required, the calibration sequence will proceed without asking if you want to perform certain operations.

M2A Transmitter Operator’s Manual 36

Chapter 7: Maintenance

Overview

This chapter describes procedures for performing preventive maintenance, troubleshooting, calibrating the M2A, and replacing field replaceable parts. It includes separate procedures for calibrating the combustible gas/CO

Preventive Maintenance

This section describes a recommended preventive maintenance schedule to ensure the optimum performance of the M2A. It includes daily, monthly, quarterly, and biannual procedures.

Daily

Verify a display reading of zero (20.9% for an oxygen M2A). Inves ti gate s ign if icant ch anges in th e reading.

/toxic and oxygen versions of the M2A.

Monthly

This procedure describes a test to verify that the M2A responds properly to the target gas.

NOTE: Performing a response tes t on the M2A may cause alarms. If you do not want external

alarms to actuate, disable any external alarms during the response test to avoid unwanted external alarm indications.

NOTE: The following procedure assumes the use of a calibration kit which includes a

calibration gas cylinder, a fixed flow regulator with an on /off knob, a calibration cup for the detector, and a short piece of sample tubing to connect the regulator to the calibration cup.

1. Disable all external alarms if external alarm indications are not desired during the response test.

2. Connect the calibration kit sample tubing to the calibration cup hose barb.

3. Screw the calibration cup onto the detector.

NOTE: For an ESM-01 detector, you must unscrew the removable splashguard from the

detector housing cap so you can push the appropriate calibration cup onto the ESM-01 sensor . Make sure to use the correct calibra tion cup for the sensor being used. There is a Cl

type calibration cup for a Cl2 sensor, an NH3 type calibration cup for an NH3

sensor, and a general type (usually labeled SO sensors.

) calibration cup for all other ESM-01

4. Connect the fixed flow regulator to the calibration cup using the sample tubing.

37 M2A Trans mitte r Op erato r’ s Manu al

NOTE: When applying gas to an NH3 ESM-01, the 0.25 LPM flowrat e reg ul at or mus t be u sed .

All other M2As require a 0.5 LPM flowrate regulator.

5. Screw the calibration gas cylinder into (onto for an H

6. Turn the regulator knob counterclockwise to open the regulator.

7. Allow calibration gas to flow for one minute.

8. Verify that the display reading is within ± 20% of the gas concentration.

NOTE: If the reading is not within ± 20% of the gas concentration, calibrate the M2A as

described in “Calibration, Combustib le Ga s, CO2, and Toxic Versions” on page 42 or “Calibration, Oxygen Version” on page 45.

9. Turn the regulator knob clockwise to close the regulator.

10. Unscrew the calibration gas cylinder from the fixed flo w regulator and unscr ew the calib ration cup from the detector. For an ESM-01 detector, pull the calibration cup off the ESM-01 sensor and screw the splashguard back onto the detector housing cap.

11. If external alarms have been disabled, enable them when the display returns to a normal fresh air reading.

12. Store the components of the calibration kit in a safe place.

S cylinder) the fixed flow regulator.

Quarterly

Calibrate M2As that do not have an IR detector as described in “Calibration, Combustible Gas, CO2, and Toxic Versions” on page 42 or “Calibration, Oxygen Version” on page 45. See “Calibration Frequency” on page 41 for a discussion of calibration frequency guidelines.

Biannually

Calibrate M2As that have an IR detector as described in “Calibration, Combustible Gas, CO2, and T oxic Versions ” on page 42. See “Calibration Frequency” on p age 41 for a discussion of calibratio n frequency guidelines.

M2A Transmitter Operator’s Manual 38

Troubleshoo ting

The troubleshooting guide describes symptoms, probable causes, and recommended action for problems you may encounter with the M2A.

NOTE: This troubleshooting guide describes M2A problems only. If the M2A is connected to a

controller, see the controller o perator’s manual for problems you may encounter with the controller.

Table 9:Troubleshooting the Combustible Gas Detector

Condition Symptom(s) Probable Causes Recommended Action

No Power The display backli ght is

off and the display screen is blank.

Frequent or Suspect Alarms

Flickering Display

The M2A alerts you to frequent or suspect alarms while the fresh air readings remain on zero (20.9 for oxygen).

The display reading flickers often.

• The power wiring is disconnected or misconnected.

• The display cable is disconnected or misconnected.

•The M2A is experiencing false readings due to RFI or EMI.

• The detector wiring is disconnected, misconnected, or intermittent.

•The M2A is experiencing false readings due to RFI or EMI.

• The noise filter setting is too low.

• The zero suppression setting is too low .

• The display screen is malfunctioning.

1. Verify that the wiring to the power sou rce or controller is correct and secure.

2. Verify that the ribbon cable connecting the terminal PCB to the control PCB is securely installed. This ribbon cable plugs into a connector on the top edge of the control PCB and on the bottom of the terminal PCB.

3. If the power dif fic ulti es con tin ue, c ont act RKI for further instruction.

1. Verify that the M2A wiring is properly shielded. See “Wiring the M2A Transmitter” on page 18.

2. Verify that the detector wiring is correct and secure.

3. Increase the alarm on delay setting in Configuration Mode.

4. If the frequent or suspect alarm difficulties continue, contact RKI for further instruction.

1. Verify that the M2A wiring is properly shielded. See “Wiring the M2A Transmitter” on page 18.

2. Verify that the detector wiring is correct and secure.

3. Increase the filt er setting in Conf iguration Mode.

4. Increase the zero suppression setting in Configuration Mode.

5. If the display difficulties continue, contact RKI for further instruction.

39 M2A Trans mitte r Op erato r’ s Manu al

Table 9:Troubleshooting the Combustible Gas Detector (Continued)

Condition Symptom(s) Probable Causes Recommended Action

Fail Condition • M2A indicates a fail

Slow or No Response/ Difficult or Unable to Calibrate

condition.

• Controller indicates a fail condition

• M2A responds slowly or does not respond to response test.

• Unable to successfully set the fresh air or span (zero for oxygen) reading during calibration.

•M2A requires frequent calibration.

Note: See “Calibration Frequency” on page 41 for calibration frequency guidelines.

• The detector wiring to the terminal PCB is disconnected or misconnected.

• The wiring from the M2A to the controller is disconnected or misconnected.

• The detector fresh air signal is low enough to cause a fail condition.

• The detector is malfunctioning.

• The terminal or display PCB is malfunctioning.

• The calibration cyl inder is low, out-dated, or defective.

• The detector is malfunctioning.

• The terminal PCB is malfunctioning.

1. Verify that the detector wiring is correct and secure.

2. Verify that the wiring between the M2A and the controller is correct and secure.

3. Calibrate the M2A.

4. If the fail condition continues, replace the detector.

5. If the fail condition continues, contact RKI for further instruction.

1. Verify that the calibration cylinder contains an adequate supply of a fresh test sample.

2. If the calibration/response difficulties continue, replace the dete ctor.

3. If the calibration/response difficulties continue, contact RKI for further instruction.

M2A Transmitter Operator’s Manual 40

Calibration Frequency

Some M2As have IR (infrared) type detectors , such as an M2A for CO2 or an LEL M2A with an IR detector. Most of the M2As do not have an IR detector. For example, an H electrochemical detector and some of the combustible M2As use catalytic detectors. The M2As that

use IR detectors typically need less frequent calibration as is discussed below. See Table 1, “M2A Specifications,” on page 2 to see which M2As are IR versions.

Although there is no particular calibration frequency that is correct for all applications, a calibration frequency of every 3 to 6 months for M2As that do not have an IR detector and every 6 to 12 months for M2As that have an IR detector is adequate for most M2A applications. Unless experience in a particular application dictates otherwise, RKI Instruments, Inc. recommends a calibration frequency of every 3 months for M2As that do not have an IR detector and every 6 months for M2As that have an IR detector.

If an application is not very demanding, for example detection in a clean, temperature controlled environment where the toxic or combustible target gas is not normally present, and calibration adjustments are minimal at calibration, then a calibration frequency of every 6 mont hs f or a non-IR M2A or 12 months for an IR M2A is adequate.

If an application is very demanding, for example if a combustible or toxic gas is present often and in significant concentrations or the environment is not well controlled, then more frequent calibration than every 3 months for a non-IR M2A or every 6 month s for an IR M2A may be necessary. For combustible gas detection with an M2A that uses a catalytic detector, if potential catalyst poisons are known or likely to be present, more frequent calibration than every 3 months will be necessary.

S M2A has an

41 M2A Trans mitte r Op erato r’ s Manu al

Calibration, Combustible Gas, CO2, and Toxic Versions

This section describes how to calibrate the combustible gas, CO2, and toxic gas versions of the M2A. It includes procedures to prepare for calibration, enter Calibration Mode, adjust the fresh air

(zero) setting, adjust the span setting, and return to normal operation. See the next section, “Calibration, Oxygen Version” for instructions to calibrate an oxygen M2A.

WARNING : The M2A is not an active gas monitoring device during th e calibration

procedure. The 4-20 mA output signal will “freeze” at 3.5 mA and all relays will remain in their non-alarm state while the M2A is in Calibration Mode. The output signal will not indicate current rea dings and the relays will not resume operating normally until the M2A is in norma l operation again.

Prepari ng for Ca libration

NOTE: The following procedure assumes the use of a calibration kit which includes a

calibration gas cylinder, a zero air cylinder, a fixed flow regulator with an on/off knob, a calibration cup for the appropriate sensor, and a short piece of sample tubing to connect the regulator to the calibration cup.

NOTE: While in the calibration program, if there is no switch activity for the calibration time-

out period the unit will return to normal operation. See “Viewing & Changing M2A Parameters” on page 31 for instructions to set the calibration time-out.

NOTE: The following procedure assumes that the target gas is present in a high enough

concentration to affect the fresh air (zero) reading. If a fresh air environment can be verified, applying zero air to the detector is not necessary when setting the zero (span for oxygen) reading.

1. Connect the calibration kit sample tubing to the calibration cup hose barb.

2. Screw the calibration cup onto the detector.

NOTE: For an ESM-01 detector, you must unscrew the removable splashguard from the

detector housing cap so you can push the appropriate calibration cup onto the ESM-01 sensor . Make sure to use the correct calibra tion cup for the sensor being used. There is a Cl

type calibration cup for a Cl2 sensor, an NH3 type calibration cup for an NH3

sensor, and a general type (usually labeled SO sensors.

3. Connect the fixed flow regulator to the calibration cup using the sample tubing.

NOTE: When calibrating an NH3 ESM-01, the 0.25 LPM flowrate regulator must be used. All

other M2As require a 0.5 LPM flowrate regulator.

) calibration cup for all other ESM-01

M2A Transmitter Operator’s Manual 42

Non-Intrusive Calibration

If the M2A is installed in a classified area and non-intrusive calibration is required, follow the instructions below, but do not remove the junction box cover. Use the magnetic wand accessory to actuate the magnetic switches instead of pushing the control switch buttons. To actuate a magnetic switch and perform the same operation as pressing a control switch button, touch the magnet in the end of the magnetic wand to the M2A’s glass cover directly above the magnetic switch you wish to actuate. Touching the glass and removing the wand is the same as pressing and releasing a button. Touching the glass and keeping the wand in place is the same as pressing and holding a button.

Calibration Gas Response Memory Feature

The M2A has the capability to “remember” the detector’s response to the calibration gas after the gas is removed from the detector during the fresh air and span adjustment procedure. This feature enables one person to perform a calibration if the detector is mounted remotely from the M2A. When zero air is applied to the M2A during a fresh air adjustment, the M2A will freeze the display reading at the lowest response and the M2A will continue to display this reading and retain it in its memory until the fresh air adjustment procedure is completed. When calibration gas is applied to the M2A during a span adjustment, the M2A will freeze the display reading at the highest response to the calibration gas. The calibration gas can then be removed and the M2A will continue to display this reading and retain it in its memory until the span adjustm e nt procedure is completed.

Adjusting the Fresh Air Reading

1. While in normal operation, press and hold the UP/YES button for 5 seconds to enter Calibration Mode. Release the button when the following screen appears.

Calib?

YES/NO

2. If you want to continue with calibration, press and release the UP/YES button. The display will indicate the target gas and CAL Mode for a few seconds before showing FreshAir Adjust?.

If you want to exit Calibration Mode, press and release the DOWN/NO button. The M2A will indicate Leaving CAL Mode and the M2A will return to normal operation.

3. T o continue with adjusting the fresh air reading, press and release the UP/YES button. ENTER will alternate with FreshAir on the top display line and the current gas reading will be on the bottom display line.

To skip adjusting the fresh air reading, press and release the DOWN/NO button. The display will indicate SPAN w/Cal Gas?. Skip to the next section, “Adjusting the Span Setting”.

4. Screw the zero air cylinder into the fixed flow regulator.

5. Turn the regulator knob counterclockwise to open the regulator.

6. Allow zero air to flow for two minutes. If there was gas present causing a reading on the M2A, the reading should decrease and stabilize after two minutes.

7. Turn the regulator knob clockwise to close the regulator.

8. Unscrew the zero air cylinder from the fixed flow regulator leaving the calibration cup on the detector. The M2A wi ll continue t o display th e minimum gas response on the displ ay and retain the response level in its memory.

9. Press and release the ENTER button. The M2A will perform a fresh air adjustment and the display will indicate SPAN w/Cal Gas?.

NOTE: If the fresh air adjustment fails, see “Troubleshooting” on page 39 for recommended

actions.

43 M2A Trans mitte r Op erato r’ s Manu al

Adjusting the Span Setting

1. If you want to continue with adjusting the span setting, press and release the UP/YES butto n. APPLY will alternate with SPAN Gas on the top display line and the current gas reading will be on the bottom display line.

If you want to skip adjusting the span reading, press and release the DOWN/NO button. The display will indicate Leaving Cal Mode and the M2A will return to normal operation.

2. Screw the calibration gas cylinder into (onto for an H

S cylinder) the fixed flow regulator.

3. Turn the regulator knob counterclockwise to open the regulator.

4. Allow calibration gas to flow for two minutes. The gas reading should be stable after two minutes.

5. Turn the regulator knob clockwise to close it.

6. Unscrew the calibration gas cylinder from the fixed flow regulator and unscre w the calibrat ion cup from the detector. For an ESM-01 detector, pull the calibration cup off of the ESM-01 sensor and screw the splashguard back onto the detector housing cap. The M2A will continue to display the maximum gas response on the display and retain the response level in its memory.

7. Adjust the gas reading up or down to match the calibration gas cylinder concentration by using the UP/YES and DOWN/NO buttons, then press and release the ENTER button.

8. The M2A will perform a span operation. The display will indicate SPAN Gas PASS for a few seconds, then indicate SPAN Gas SAVED before indicating Leaving CAL Mode for a few seconds.

NOTE: If the span adjustment fails, see “Troubleshooting” on page 39 for recommended

actions.

9. The display will now alternate between the normal operation screen and the message REMOVE CAL GAS for 1 minute. If the calibration gas has not been removed from the detector, remove it now to avoid unwanted alarms.

During this 1 minute period, the signal output will remain fixed at 3.5 mA and the relays will remain in their non-alarm state to avoid unwanted alarms wh ile the calibration gas clears fr om the detector. At the end of the 1 minute period, the REMOVE CAL GAS message will stop appearing and the M2A will return to normal operation.

10. Store the components of the calibration kit in a safe place.

M2A Transmitter Operator’s Manual 44

Calibration, Oxygen Version

This section describes how to calibrate the oxygen version of the M2A. It includes procedures to prepare for calibration, enter Calibration Mode, set the fresh air (span) reading, set the zero reading, and return to normal operation.

WARNING : The M2A is not an active gas monitoring device during th e calibration

procedure. The 4-20 mA output signal will “freeze” at 17.4 mA and all relays will remain in their non-alarm state while the M2A is in Calibration Mode. The output signal will not indicate current rea dings and the relays will not resume operating normally until the M2A is in norma l operation again.

Prepari ng for Ca libration

NOTE: The following procedure assumes the use of a calibration kit which includes a zero air

(20.9% oxygen) calibration cylinder to set the fresh air reading, a 100% nitrogen (0% oxygen) calibration gas cylinder to set the zero reading, a fixed flow regulator with an on/off knob, a calibration cup, and a short piece of sample tubing to connect the regulator to the calibration cup. A cylinder with up to an 18% oxygen concentration may be used instead of a 100% nitrogen cylinder to set the zero reading.

NOTE: While in calibration mode, if there is no switch activity for the calibration time-out

period the unit will return to normal operation. See “Viewing & Changing M2A Parameters” on page 31 for instructions to set the calibration time-out.

NOTE: The following procedure assumes that the oxygen concentration in the calibration area

is not normal, 20.9%, but is oxygen deficient. If a fresh air environment can be verified, applying zero air to the detector is not necessary when adjusting the fresh air (span) setting.

1. Connect the calibration kit sample tubing to the calibration cup hose barb.

2. Screw the calibration cup onto the detector.

3. Connect the fixed flow regulator to the calibration cup using the sample tubing.

Non-Intrusive Calibration

Calibration Gas Response Memory Feature

The M2A has the capability to “remember” the detector’s response to the calibration gas after the gas is removed from the detector during the fresh air or zero adjustment procedure. This feature enables one person to perform a calibration if the detector is mounted remotely from the M2A. When zero air is applied to the M2A during a fresh air adjustment, the M2A will freeze the display

45 M2A Trans mitte r Op erato r’ s Manu al

reading at the highest response and the M2A will continue to display this reading and retain it in its memory until the fresh air adjustment procedure is completed. When calibration gas is applied to the M2A during a zero adjustment, the M2A will freeze the display reading at the lowest response to the calibration gas. The calibration gas can then be removed and the M2A will continue to display this reading and retain it in its memory until the zero adjustment p roced ure is completed.

Adjusting the Fresh Air Setting

1. While in normal operation, press and hold the UP/YES button for 5 seconds to enter Calibration Mode. Release the button when the following screen appears.

Calib? YES/NO

2. If you want to continue with calibration, press and release the UP/YES button to continue. The display will indicate OXYGEN CAL Mode for a few seconds before showing FreshAir Adjust?.

If you want to exit Calibration Mode, press and release the DOWN/NO button. The M2A will indicate Leaving CAL Mode and the M2A will return to normal operation.

3. To continue with ad jus ting the fresh air (span) reading, press and release the UP/YES button. ENTER will alternate with FreshAir on the top display line and the current oxygen reading will be on the bottom display line.

To skip adjusting the fresh air reading, press and release the DOWN/NO button. The display will indicate ZERO w/Cal Gas?. Skip to the next section, “Adjusting the Zero Setting”.

4. Screw the zero air cylinder into the fixed flow regulator.

5. Turn the regulator knob counterclockwise to open the regulator.

6. Allow zero air to flow for 2 minutes. If the oxygen concentration in the area is less than 20.9, the reading should stabilize after 2 minutes.

7. Turn the regulator knob clockwise to close the regulator.

8. Unscrew the zero air cylinder from the fixed flow regulator leaving the calibration cup on the detector. The M2A will continue t o display th e maximum ga s response on the display and retain the response level in its memory.

9. Press and release the ENTER button. The M2A will perform a fresh air adjustment and the display will indicate ZERO w/Cal Gas?.

NOTE: If the fresh air adjustment fails, see “Troubleshooting” on page 39 for recommended

actions.

Adjusting the Zero Setting

1. If you want to continue with adjusting the zero setting, press and release the UP/YES button. APPLY will alternate with ZERO Gas on the top display line and the current oxygen reading will be on the bottom display line.

If you want to skip adjusting the zero reading, press and release the DOWN/NO button. The display will indicate Leaving Cal Mode and the M2A will return to normal operation.

2. Screw the 100% nitrogen gas cylinder into the fixed flow regulator.

3. Turn the regulator knob counterclockwise to open the regulator.

4. Allow gas to flow for 2 minutes. The gas reading should be stable after 2 minutes.

M2A Transmitter Operator’s Manual 46

5. Turn the regulator knob clockwise to close the regulator.

6. Unscrew the nitrogen cylinder from the fixed flow regulator and unscrew the calibration cup from the detector. The M2A will continue to display the minimum gas response on the display and retain the response level in its memory.

7. Adjust the oxygen reading up or down to match the 100% nitrogen cylinder oxygen concentration of 0 by using the UP/YES and DOWN/NO buttons.

NOTE: If a cylinder other than a 100% nitrogen (0% oxygen) cylinder is used to set the zero

reading, such as a cylinder with 12% oxygen, set the zero reading to match the cylinder’s oxygen concentration.

8. Press and release the ENTER button. The M2A will perform a zero operation. The display will indicate ZERO Gas PASS for a few seconds, then indicate ZERO Gas SAVED before indicating Leaving CAL Mode for a few seconds.

NOTE: If the zero adjustment fails, see “Troubleshooting” on page 39 for recommended

actions.

9. The display will now alternate between the normal operation screen and the message REMOVE CAL GAS for 1 minute. If the calibration gas has not been removed from the detector remove it now to avoid unwanted alarms.

During this 1 minute period, the signal output will remain fixed at 17.4 mA and the relays will remain in their non-alarm state to avoid unwanted alarms wh ile the calibration gas clears fr om the detector. At the end of the 1 minute period, the REMOVE CAL GAS message will stop appearing and the M2A will return to normal operation.

10. Store the components of the calibration kit in a safe place.

Replacing Components of the M2A

Replacing the Gas Detector

NOTE: For M2A versions that do not have a replaceable plug-in sensor, or if you determine

that it is necessary to replace the entire detector, use the procedure in this section to change the entire detector. For M2A versions that include a replaceable plug-in sensor, see the appropriate instructions in the sections that follow this one to replace the plug-in sensor.

1. Turn off or disconnect power to the M2A.

2. Remove th e junction bo x cover.

3. Grasp the control PCB by its edges.

4. Gently pull until the control PCB is pulled away from the banana jacks. Take care not to pull too hard and damage the cable which connects the control and terminal PCBs.

5. Let the control PCB hang by the cable. The terminal strips are now visible on the terminal PCB. The control PCB may be left hanging while wiring is done. If desired, the control PCB may be disconnected from the cable and set aside while wiring.

6. Remove th e detector terminal stri p from its socket.

7. Disconnect the detector leads from the detector terminal strip. Note the position of the color-

47 M2A Trans mitte r Op erato r’ s Manu al

coded leads as you remove them.

8. Unscrew the detector from the junction box.

9. Guide the replacement detector leads through the bottom con du it hub o f the junction box, then screw the mounting threads of the detector into the conduit hub.

10. Connect the detector leads to the detector terminal strip as follows:

• Catalytic Combustible Gas Detector, IR Combustible Gas Detector, and IR CO

Detector

Red wire to terminal labeled LEL RED, white to terminal labeled LEL WHT, green wire to terminal labeled LEL GRN, black wire to terminal labeled LEL BLK.

• CO or H2S gas detector.

Red wire to terminal labeled TOXIC +, black wire to terminal labeled TOXIC -.

• ESM-01 Gas Detector

Color coded wire to terminal labeled TOXIC +, black wire to terminal labeled TOXIC -. See Figure 25, “ESM-01 Toxic Detector Wiring” on page 21 for the wire color coding.

• Oxygen gas detector.

Green wire to terminal labeled OXY +, white wire to terminal labeled OXY -.

11. Re-install the detector terminal strip into its socket.

12. Re-install the control PCB (and ribbon cable if necessary). Be sure the ribbon cable is routed down below the control PCB so it will not be damaged by the cover when it is screwed back on.

13. Secure the junction box cover to the junction box.

14. Turn on or reconnect power to the M2A.

NOTE: Allow the replacement detector to warm up for 15 minutes before you continue with the

next step.

15. Calibrate the replacement detector as described in “Calibration, Combustible Gas, CO2, and Toxic Versions” on page 42 or “Calibration, Oxygen Version” on page 45.

Replacing the CO or H2S Plug-in Sensor

NOTE: This procedure is applicable for both the CSA type, explosion proof CO and H2S

detectors and the non-explosion proof CO and H2S detectors.

1. Turn off or disconnect power to the M2A.

2. Unscrew the detector cap from the housing body. Make sure not to lose the cap gasket. See Figure 4 - Figure 7 for illustr a tions of the CO or H

3. Unplug and remove the sensor.

4. If you are replacing a CO sensor, remove the rubber boot and charcoal filter from the old sensor.

NOTE: RKI instruments recommends replacing the charcoal disk filter whenever a CO sensor

is replaced.

If you are replacing the 65-2423RK-05 explosion-proof H

S detectors.

S detector’s sensor, remove the

M2A Transmitter Operator’s Manual 48

rubber boot and spacer from the old sensor.

5. If you are replacing a CO sensor, install the rubber boot and charcoal filter onto the new sensor’s face.

If you are replacing the 65-2423RK-05 explosion-proof H

S detector’s sensor, install the

rubber boot and spacer on the new sensor’s face.

6. Carefully match the replacement sens or’ s male pi ns with the 4- socket patter n in the top section and plug it in.

7. Make sure the cap gasket is in place and screw the detector cap back onto the housing body.

8. Turn on or recon nect power t o the M2A.

CAUTION: Allow the replacement sensor to warm up for 15 minutes before you continue with

the next step.

9. Calibrate the detector as described in “Calibration, Com bustible Gas, CO2, and Toxic Versions” on page 42.

Replacing the CO Sensor Charcoal Filter

The charcoal filter is used to scrub out interfering gases from the environment being monitored, such as H

CO M2A, the charcoal filter may be saturated and no longer scrubbing out interfering gases and it may be necessary to change the charcoal filter.

1. Turn off or disconnect power to the M2A.

2. Unscrew the detector housing cap from the housing body. Make sure not to lose the cap gasket.

3. Remove the rubber retaining boot with the charcoal filter disk from the sensor.

4. Replace the charcoal filter disk in the rubber retaining boot and install the boot onto the sensor.

S and certain hydrocarbons. If you are experiencing unexplained upscale readings on a

See Figure 4 for an illustration of the CO detector.

5. Make sure that the cap gasket is in place and screw the detector cap back onto the housing body.

6. Turn on or recon nect power t o the M2A.

Replacing an Oxygen Plug-in Sensor

NOTE: This procedure is applicable for both the CSA type, explosion proof oxygen detector

(65-2514RK) and non-explosion proof, replaceable sensor oxygen detector (652494RK).

1. Turn off or disconnect power to the M2A.

2. Unscrew the detector cap from the detector hou sing b ody. Take care not to lose the cap gasket. See Figure 2 or Figure 3 for an illustration of the oxygen detect or.

3. Unplug and remove the sensor.

4. Carefully match the replacement sens or’ s male pi ns with the 2- socket patter n in the top section and plug it in.

5. Make sure the cap gasket is in place and screw the detector cap back on to the detector housing.

6. Turn on or recon nect power t o the M2A.

49 M2A Trans mitte r Op erato r’ s Manu al

NOTE: Allow the replacement sensor to warm up for 15 minutes before you continue with the

next step.

7. Calibrate the detector as described in “Calibration, Com bustible Gas, CO2, and Toxic Versions” on page 42.

Replacing an ESM-01 Plug-in Sensor

1. Turn off or disconnect power to the M2A.

2. Unscrew the detector cap from the detector hou sing b ody. Take care not to lose the cap gasket. If the splashguard begins to unscrew from the detector cap, make sure to remove the detector cap also. See Figure 8 for an illustration of the ESM-01 detector.

3. Unplug and remove the sensor.

4. Carefully match the replacement sensor’s plug with the socket in the housing body and plug it in.

W ARNING: The ESM-01 detectors cannot be changed from one type to another. Replace the

plug-in sens or only with th e same type of E S M-01 sensor.

5. Make sure the cap gasket is in place and screw the detector cap back onto the housing body. If the splash guard was unscrewed from the detector cap, screw it back onto the detector cap.

6. Turn on or recon nect power t o the M2A.

NOTE: Allow the replacement sensor to warm up for 15 minutes before you continue with the

next step.

7. Calibrate the detector as described in “Calibration, Com bustible Gas, CO2, and Toxic Versions” on page 42

M2A Transmitter Operator’s Manual 50

Chapter 8: RS-485 Modbus Output

Overview

This chapter describes the M2A’s RS-485 Modbus output and how to configure the M2A to make use of it. It also discusses how to wire the M2A into a Modbus system.

The M2A provides an RS-485 serial communications interface. It is a Modbus Slave Device, supporting 2-wire RS-485 Modbus RTU serial communications.

Wiring the M2A in a Modbus System

The M2A is a 2-wire Modbus RTU device. When wiring the M2A into a Modbus system, adhere to standard Modbus wiring practices per the Modbus Over Serial Line Specification and Implementation Guide V1.0 or later. This document can be found online at www.modbus.org/ specs.php.

The Modbus protocol supports a maxi mum of 247 uni qu e slave add ress es (1-2 47). The M2A ’s line driver provides for up to 128 M2As to be connected together without the need for a repeater. Figure 29 & Figure 30 below illustrate typical M2A wiring configurations. If more than 128 M2As need to be connected together, RS-485 repeater(s) should be used such that no more than 128 M2As reside on any given ne twork segment.

CAUTION: The network segment can only support 128 units if RKI M2As are being used. The

use of any other instruments will lower the number of units that may reside on any given network segment.

The MODBUS terminal strip is located on the terminal PCB (see Figure 9). The following signals are available at the Modbus terminal strip:

Table 10 : Modbus Termi nal Strip Signals

Modbus Terminal Label (RS-485

Name)

AD0 BD1 CCommon

Modbus Signal Name

Ground Jumper

The M2A includes a 2-pin ground header (see Figure 9) that is used when the M2A is used in a Modbus system. Every M2A is supplied with a ground jumper (a jumper block) installed onto this header. If the M2A isn’t wired into a Modbus system or if it is wired into one as shown in Figure 28, the ground jumper should be installed. If the M2A is wired in a Modbus system as shown in Figure 27, the ground jumper should be removed.

51 M2A Trans mitte r Op erato r’ s Manu al

Recommended Modbus Wiring

The recommended Modbus wiring for the M2A is illustrated in Figure 27 below. In this configuration, 5 wires are used for wiring the M2A into a Modbus system. Figure 27 also illustrates typical alarm device wiring. The ground jumper must be removed in this wiring configuration.

Power Su pply

10-30 VDC

Remove Ground Jumper

Input

Terminals

Modbus Controller

Comm on

D1 D0

FAIL

C NC NO

ALARM 1

C NC NO

ALARM 2

C NC NO

See

Detector

Wiring

- S +

LEL

R W G B

RS 485 PW R/SIG

A B C

Figure 27: Recommended Modbus Wiring

See

Detector

Wiring

- S +

LEL

R W G B

RS 485 PW R/SIG

A B C

FAIL

C NC NO

ALARM 1

C NC NO

ALARM 2

C NC NO

Additiona

M2As

Power Supply

10-30 VDC

Input

Terminals

Adding an M2A to an Existing M2 Modbus Installation with Recommended Wiring

An M2A can be wired into an existing M2 Modbus system. The shape of the terminal PCB will be different but the wiring connections are identical and the ground jumper on the M2A must still be removed.

Alternate Modbus Wiring For Existing Installations

Although the wiring shown in Figure 27 is recommended, it is possible to wire the M2A into a Modbus system with only 4 wires in situations where a pre-existing system is being replaced and wiring is already in place. This should only be done if wiring for a system that is being replaced is already installed and it is not practical to run another wire. See Figure 28 below for this wiring configuration. In this configuration, the wire between the “C” terminal on the M2A and the Common terminal on the Modbus controller is omitted. Instead, the Common terminal on the Modbus controller is connected to the “-” of the 24 VDC power supply. The ground jumper mus t be installed in this wiring configuration.

Comm on

D1 D0

See

Detector

Wiring

- S +

LEL

R W G B

RS 485 PWR/SIG

A B C

FAIL

C NC NO

See

ALARM 1

C NC NO

ALARM 2

C NC NO

Detector

Wiring

- S +

LEL

R W G B

RS 485 PWR/SIG

A B C

FAIL

C NC NO

ALARM 1

C NC NO

ALARM 2

C NC NO

Additiona

M2As

Modbus Controller

Figure 28: Alternate Modbus Wiring

M2A Transmitter Operator’s Manual 52

ID = 128

M2A

Termination

Jumper

Installed

Adding an M2A to an Existing M2 Modbus Installation with Alternate Wiring

An M2A can be wired into an existing M2 Modbus system. The shape of the terminal PCB will be different but the wiring connections are identical and the ground jumper on the M2A must still remain installed.

Termination Jumper

The M2A includes a 2-pin termination header (see Figure 9) that is used when the M2A is used in a Modbus system. Every M2A is supplied with a termination jumper (a jumper block) installed onto this header. If the M2A is not used in a Modbus system, this jumper has no function. When the M2A is installed in a Modbus system, this jumper must be installed in an M2A that is at the end of a Modbus line. Any M2A in a Modbus system that is not at the end of a line must have the termination jumper removed (see Figure 29 & Figure 30 below).

Modbus

Master

RS-485 RS-48

M2A

Termination

Jumper

Not Installed

Up to 12 8 M2As canbe connected without a repeater

M2A

Termination

Jumper

Not Installed

ID = 126ID = 127

Figure 29: Multiple M2As in a Daisy Chain Configuration

M2A

Termination

Jumper

Not Installed

ID = 125

M2A

Termination

Jumper

Not Installed

ID = 1

53 M2A Trans mitte r Op erato r’ s Manu al

ID = 1

M2A

Termination

Jumper

Installed

RS-485

M2A

Termination

Jumper

Not Install ed

Termination

Not Installed

ID = 2 ID = 3

Up to 128 M2As can be connected without a repeater

Figure 30: Multiple M2As in a Two Branch Configurati on

M2A

Jumper

Modbus

Master

M2A

Termination

Jumper

Not Installed

ID = 4

ID = 128

M2A

Termination

Jumper

Installed

RS-485

M2A

Termination

Jumper

Not Install ed

ID = 127

Using the M2A in a 4-wire Modbus System

Although the M2A is a 2-wire Modbus R TU device, it can be used with a 4-wire Modbus controller if the system wiring is modified as follows:

• Connect the controller’s TxD0 and RxD0 wires together and use this connection as the 2-wire Modbus D0 signal.

• Connect the controller’s TxD1 and RxD1 wires together and use this connection as the 2-wire Modbus D1 signal.

• Connect these D0 and D1 signals and the common wire from the controller to the 2-wire Modbus Network of M2As.

Modbus Mode

Modbus Mode allows you to configure various parameters relating to the Modbus setup of the M2A. Modbus Mode includes a 5-minute time-out feature. If you do not press a control button for 5 minutes, the M2A automatically returns to normal operation.

NOTE: If the M2A returns to normal operation because of a time-out, it enters a warm-up

period just as it does when it is first turned on.

1. While in normal operation, simultaneously press and hold the DOWN/NO and ENTER buttons

M2A Transmitter Operator’s Manual 54

for 5 seconds to enter Modbus Mode. Release the buttons when the following screen appears.

Set Up Modbus?

2. To exit Modbus Mode, press and release the DOWN/NO button. The M2A will return to normal operation.

To continue in Modbus Mode, press and release the UP/YES button. The current ENABLED/ DISABLED setting will appear.

3. If you want to change the currently displayed parameter, use the UP/YES and DOWN/NO buttons to adjust it to the desired setting, then press ENTER to continue to the next parameter.

If the currently displayed parameter setting is OK, press the ENTER button to proceed to the next parameter.

T able 11 lists the M2A Modb us Mode par ameters you can set. Table 11 also lists the fact ory set value for each parameter.

55 M2A Trans mitte r Op erato r’ s Manu al

Table 11: Configuration Parameters

Modbus Mode Parameter Available Settings & Description

Enabled/Disabled Can be set to ENABLED or DISABLED (factory setting).

Enables or disables the Modbus output .

Slave ID The Slave ID can be set to values from 1 (factory setting) to 247.

The M2A will only receive messages from t he M aster which are addressed to

this Slave ID (except for broadcast messages whic h are received by all slaves). Baud Rate Can be set to 1200, 2400, 4800, 9600 (factor y setting), 14440, & 19200. Parity EVEN (factory setting), ODD, NONE Response Delay The response delay can be set from 0 (factory setting) to 20 mS.

This is an optional additional delay inserted by the M2A prior to returning a

response message to the Master. It may be helpful in some installations where

the Master’s preparedness to receive responses might be delayed.

4. When you have scrolled through all the adjustable parameters, SA VE IT? YES/NO appears on

the display.

5. If you do not wish to save the adjustments, press and release the DOWN/NO button. The DO

OVER? YES/NO message will display. Press and release the DOWN/NO button. The ABORT? YES/NO message will display. Press the UP/Y ES button to return to normal

operation.

If you wish to change some of the adjustments made, pr ess and release the DOWN/NO button. The DO OVER? YES/NO message will display. Press and release the UP/YES button. The Re-do MB Setup message will display and the M2A will return to the first adjustable parameter. Go back to step 3 and continue.

If you want to save the adjustments made, press and release the UP/YES button. Modbus

Saved is indicated on the display for a few seconds and the M2A returns to normal operation.

NOTE: All M2As on a Modbus network must be configured w ith the same baud r ate and parity,

and each M2A must have a unique slave ID. For an M2A to participate on a network, the ENABLED/DISABLED setting must be set to ENABLE.

M2A Transmitter Operator’s Manual 56

Supported Modbus Functions

The M2A supports Function Code 03: Read Holding Registers and Function Code 16: Write Registers.

Function Code 03: Read Holding Registers

There are a total of 40 registers available to be read via this Function Code.

Registers 1 - 2

The format (bit & field assignments) for registers 1 - 2 is shown below in Table 12 - Table 13.

Table 12: Register 1, Numerical Reading with Sign & Decimal Point Bit & Field Assignments

Bit(s) Value & Field

[15] Sign of Reading

0 = Positive

1 = Negative [14:13] Format of Reading

0 = XXX (no decimal point)

1 = XX.X

2 = X.XX

3 = .XXX [12:0] Numerical value of display reading (8000 max)

Table 13 : Register 2, Operating State, Alarms & Relay s B it & Field Assignments

Bit(s) Value

[15:12] Operating State

0 = Undefined

1 = Initialization

2 = Normal

3 = Warm-up

4 = Fail

5 = Calibration

6 = Post-Calibration

7 = Low Power

8 = Setup [11] Gas Type Change

0=Not Changed

1=Changed [10] Configuration Change

0=Not Changed

1=Changed [9] Calibration Activity Flag

0=No Calibration Activity

1=Calibra tion Activ ity Has Occu rred [8] Fail Status

0 = Fail Not Asserted

1 = Fail Asserted

57 M2A Trans mitte r Op erato r’ s Manu al

Table 1 3: Register 2, Operating State, Alarms & Relays Bit & Field Assignments ( Continued)

Bit(s) Value

[7:6] Alarm 2 Status

0 = No Alarm

1 = Unacknowledged Alarm

2 = Acknowledged Alarm

3 = Unused Code [5:4] Alarm 1 Status

0 = No Alarm

1 = Unacknowledged Alarm

2 = Acknowledged Alarm

3 = Unused Code [3] Overscale Status

0 = Not Overscale

1 = Overscale [2] Fail Relay Status

0 = Not Energized

1 = Energized [1] Alarm 2 Relay Status

0 = Not Energized

1 = Energized [0] Alarm 1 Relay Status

0 = Not Energized

1 = Energized

Registers 4 - 11

The 16 bytes in these registers contain the same ASCII text information that is displayed on the M2A’s OLED (not NULL Terminated).

Registers 15 - 19

Registers 15 - 19 are the Gas Name ASCII String (NULL Terminated).

Registers 20 - 22

Registers 20 - 22 are the Gas Units String (NULL Terminated).

M2A Transmitter Operator’s Manual 58

Register 33 is zero suppression. Toxics and LEL: 0%-6% of full scale Oxygen: 0%-0.7% Oxygen The decimal point location is the same as specified in Register 1.

59 M2A Trans mitte r Op erato r’ s Manu al

Calibration Outcome Codes:

1=Sensor Missing 2=Sensor Too Weak 3=Signal Too Strong 4=Not Enough Span 5=Negative Reading 6=Span Gas Value Is Not OK 7=Calculated Zero Is Too Low 8=Calculated Zero Is Too High 9=Zero Failure 10=Span Failure 11=Calibration Is Overscale 12=LEL Sensor Offset Is Too High 13=LEL Null Operation Failed 14=Operation Not Performed

M2A Transmitter Operator’s Manual 60

Function Code 16: Write Registers

There are 21 registers in Function Code 16 that can be used to write to the M2A. This manual only describes Register 16 because it can be used to reset an alarm condition. For a complete description of Function Code 16, request Appendix C from RKI Instruments, Inc.

Register 16 performs the same function as the ENTER button on the M2A. It is useful for remotely silencing alarms. With the M2A in an alarm condition, bit [0] can be used to silence it.

Table 14: Register 16, Button Function

NOTE: Register 40 in Function Code 03, the remote configuration register, must be set to 1 in

order for Register 16 to work.

Bit Value & Field

[0] ENTER (used for “Alarm Reset”)

0=Not Pressed

1=Pressed

Parts List

Table 15 lists replacement parts and accessories for the M2A Transmitter.

Table 15: Parts List

Part Number Description

06-1248RK Calibration kit sample tubing (3/16 in. x 5/16 i n.; specify length when ordering) 07-0033RK Cap gasket, for CSA type CO and H

07-0125RK Cap gasket, for ESM-01 detector 07-0203RK Rubber retaining boot for charcoal filter and for 65-2423RK-05 H2S detector

14-2101RK Spacer for 65-2423RK-05 H

18-0431RK-01 Junction box 33-7101RK Charcoal filter disk 45-6132RK Termination and group jumper 61-0140RK LEL detector, catalytic type, UL version 61-0140RK-05 LEL detector, catalytic type, CSA version 61-0190RK-CH4 CH

LEL detector, IR type

S detector

61-0190RK-HC HC LEL detector, IR type, propane calibration 61-0191RK-02 CO

61-0191RK-03 CO

61-0191RK-05 CO

61 M2A Trans mitte r Op erato r’ s Manu al

detector, IR type, 0 - 5,00 0 ppm

detector, IR type, 0 - 5% volume

detector, IR type, 0 - 50.0% volume

Table 15: Parts List

Part Number Description

61-0191RK-10 CO

61-0192RK-CH4 CH

61-0198RK-02 CO

61-0198RK-03 CO

61-0198RK-05 CO

61-0198RK-10 CO

detector, IR type, 0 - 100% volume

detector, IR type, replaceable sensor, 0 - 5000 ppm

detector, IR type, replaceable sensor, 0 - 5% volume

detector, IR type, replaceable sensor, 0 - 50.0% volume

detector, IR type, replaceable sensor, 0 - 100% volume

65-1025RK Plug-in oxygen sensor, for 65-2514RK 65-2300RK-ASH3 ESM-01 detector, 0 - 1.50 ppm arsine 65-2300RK-CL-1 0 ESM-01 detector, 0 - 10.0 ppm chlorine 65-2300RK-CL2 ESM-01 detector, 0 - 3.00 ppm chlorine 65-2300RK-NH3 ESM-01 detector, 0 - 75.0 ppm ammonia 65-2300RK-NO ESM-01 detector, 0 - 100 ppm nitric oxide 65-2300RK-PH3 ESM-01 detector 0 - 1.00 ppm phosphine 65-2300RK-SO2 ESM-01 detector, 0 - 6.00 ppm sulphur dioxide 65-2423RK-05 H

S detector assembly, CSA version

65-2433RK-05 CO detector assembly, CSA version 65-2494RK Oxygen detector assembly, non-explosion proof, r e placeable sensor 65-2495RK H2S detector assembly, 0 - 100 ppm, non-explosion proof, replaceable sensor

65-2496RK CO detector assembly, 0 - 300 ppm, non-explosion proof, replaceable sensor 65-2510RK Oxygen detector, partial pressure type 65-2511RK Oxygen detector, capillary type 65-2514RK Oxygen detector , CSA version , capilla ry type 71-0305RK M2A Transmitter Operator’s Manual (this document) 81-0002RK-01 Calibration cylinder, 50% LEL hydrogen in air, 34 liter steel 81-0002RK-03 Calibration cylinder, 50% LEL hydrogen in air, 103 liter steel 81-0004RK-01 Ca libration cylinder, 50% LEL propane in air, 34 liter steel 81-0004RK-03 Calibration cyli nder, 50% LEL propane in air, 103 liter steel 81-0007RK-01 Calibration cylinder, 15% LEL hexane in air, 34 liter steel 81-0012RK-01 Ca libration cylinder, 50% LEL methane in air, 34 liter steel 81-0012RK-03 Ca libration cylinder, 50% LEL methane in air, 103 liter steel 81-0013RK-01 Calibration cylinder, 50% volume methane in nitrogen, 34 liter steel

M2A Transmitter Operator’s Manual 62

Table 15: Parts List

Part Number Description

81-0013RK-05 Calibration cylinder, 50% volume methane in nitrogen, 58 liter steel 81-0064RK-01 Calibration cylinder, CO, 50 ppm in air, 34 liter steel 81-0064RK-03 Calibration cylinder, CO, 50 ppm in air, 103 liter steel 81-0070RK-01 Calibration cylinder , CO

81-0070RK-03 Calibration cylinder , CO

81-0072RK-01 Calibration cylinder , CO

81-0072RK-03 Calibration cylinder , CO

81-0073RK-01 Calibration cylinder , CO

81-0073RK-03 Calibration cylinder , CO

, 2,000 ppm in nitrogen, 34 liter steel

, 2,000 ppm in nitrogen, 103 liter steel

, 2.5% in nitrogen, 34 liter st ee l

, 2.5% in nitrogen, 103 liter steel

, 15% in nitrogen, 34 liter steel

, 15% in nitrogen, 103 liter steel

81-0076RK-01 Zero air calibration cylinder, 34 liter steel 81-0076RK-03 Zero air calibration cylinder, 103 liter steel 81-0078RK-01 Calibration cylinder, 100% nitrogen, 34 liter steel (used for setting oxygen zero) 81-0078RK-03 Calibration cyl inder, 100% nitrogen, 103 liter steel (used for setti ng oxygen zero) 81-0151RK-02 Calibration cylinder , H

81-0151RK-04 Calibration cylinder , H

81-0170RK-02 Calibration cylinder , 5 ppm SO

81-0170RK-04 Calibration cylinder , 5 ppm SO

81-0175RK-02 Calibration cylinder, 10 ppm NH

S, 25 ppm in nitrogen, 58 liter aluminum

S, 25 ppm in nitrogen, 34 liter aluminum

in nitrogen, 58 liter

in nitrogen, 34 liter

in nitrogen, 58 liter

81-0175RK-04 Calibration cylinder, 10 ppm NH

in nitrogen, 34 liter

81-0185RK-02 Calibration cylinder , 0.5 ppm PH3 in nitrogen, 58 liter 81-0185RK-04 Calibration cylinder , 0.5 ppm PH3 in nitrogen, 34 liter 81-0190RK-02 Calibration cylinder, 5 ppm Cl2 in nitrogen, 58 liter

81-0190RK-04 Calibration cylinder, 5 ppm Cl

81-0192RK-02 Calibration cylinder, 2 ppm Cl

81-0192RK-04 Calibration cylinder, 2 ppm Cl

in nitrogen, 34 liter

in nitrogen, 58 liter

in nitrogen, 34 liter

81-1050RK Regulator, with gauge and knob, 0.5 liter/minute continuous flow, for combustible

gas, nitrogen, zero air, and CO cylinders. 81-1051RK Regulator, with gau ge an d k n ob , 0.5 lite r/m in ut e con tinu o us flo w, for H2S cylinder 81-1051RK-25 Regulator, fixed flow, w/gauge & knob, 0.25 LPM, for 34 liter aluminum/58 liter/

103 liter cylinder (Used to calibrate NH3 ESM-01 M2A only)

81-1103RK Calibration c up, for 3/4” NPT IR detectors, combus tible gas and CO

63 M2A Trans mitte r Op erato r’ s Manu al

Table 15: Parts List

Part Number Description

81-1117RK Calibration cup, for catalytic LEL, CO, H2S, and oxygen detectors 81-1138RK Calibration cup, general ( SO

81-1138RK-CL2 Calibrati on cup, for ESM-01 Cl2, use 0.5 LPM flow 81-1138RK-NH3 Calibration cup, for ESM-01 NH3, use 0.25 LPM flow 81-1190RK Splashguard, for ESM-01 detector cap ES-1531-CO CO sensor, plug -i n ES-1537-H2S H2S sensor, plug-in ESM-015-NO ESM-01 plug-in sensor, 0 - 100 ppm nitric oxide ESM-01DH-ASH3 ESM-01 plug-in sensor, 0 - 1.50 ppm arsine ESM-01DH-D-SO2 ESM-01 plug-in sensor, 0 - 6.00 ppm sulphur dioxide, diffusion type only ESM-0DH-PH3 ESM-01 plug- in sensor, 0 - 1.00 ppm phosphine ESM-01R-D-NH3 ESM-01 plug-in sensor, 0 - 75.0 ppm ammonia, diffusion type only ESM-K01-D-CL2 ESM-01 plug-in sensor, 0 - 3.00 ppm chlorine, diffus ion type only ESM-K01D-CL2-10 ESM-01 plug-in sensor, 0 - 10.0 ppm chlorine, diffusion type only NC-6205-01 Hydrogen specific LEL detector, catalytic type, UL version NC-6205-05 Hydrogen specific LEL detector, catalytic type, CSA version

), for ESM-01, use 0.5 LPM flow

M2A Transmitter Operator’s Manual 64

Appendix A: Control Button Quick Reference Guide

The M2A’s control buttons allow access to operational modes, resetting of alarms, and display of the Information Screen. Table 16 shows which button combinations perform these functions and which parameters are available for adjustment while in the operational modes. While in these modes, display prompts showing a “?” require you to respond by pressing either the UP/YES (for yes) or DOWN/NO (for no) button. To change parameter settings, u se the UP/YES an d DOWN/NO buttons to get the desired setting, then press and release the ENTER button to accept the setting.

Table 16: Control Button Quick Reference Chart

Mode Entered or

Function Performed

Alarm Reset P ress and Release

Show Information Screen Press and Hold

Calibration Mode Press and Hold UP/

Configuration Mode Press and Hold UP/

Gas Type Mode Press and Hold UP/

Button

Combination

ENTER

DOWN/NO

YES for 5 seconds

YES & ENTER for 5 seconds

YES and DOWN/ NO for 5 seconds

Adjustable or Viewable Parameters

n/a

• Input Voltage

• M2A Version/Revision Information

• Fresh Air Adjust

• Span (or Zero for Oxygen) Adjust with Calibration Gas

•Alarm Levels

• Increasing or Decreasing Alarms

• Normally Energized or Normally De-energized Relays

• Latching or Self-resetting Alarms

• Alarm On Delay

• Alarm Off Delay (if self-resetting)

• Zero Suppression

• Noise Filter

• Calibration Time-out Period

Gas Type

Modbus Mode Press and Hold

DOWN/NO and ENTER for 5 seconds

65 M2A Trans mitte r Op erato r’ s Manu al

• Enable or Disable Modbus

•Slave ID

•Baud Rate

•Parity

• Response Delay

Appendix B: PLC and DCS Device Wiring

The M2A can be wired to a PLC or DCS device if desired.

1. Guide multi conductor shielded cable or cables or wires in conduit through the top conduit hub of the junction box. The number of cables or wires needed will depend on whether any relays are used and whether the Modbus output is used. Use the following recommendations to determine how to wire the M2A:

• If Modbus connections will not be used and only the PWR/SIG terminal stri p conn ect ions

will be used, use four conductor shielded cable or four wires in conduit for connections to the power/signal terminal strip.

Table 17: Wire Size for PWR/SIG Connections

Max Distance to Controller

w/18 Gauge Wire

2,500 ft. 5,000 ft. 8,000 ft.

• If the PWR/SIG terminal strip connections and one or more relays are used, route the

connections to the M2A in conduit. Use shielded cable in the conduit for the PWR/SIG connections and unshielded cable or individual wi res for the relay conn ections . Make su re any wire or cable used for relay wiring is appropriately rated for the power that it will carry.

NOTE: If shielded cable is used for the PWR/SIG connections, leave the cable shield’s drain

wire insulated and disconnected at the M2A. You will connect the opposite end of the cable’s drain wire at the controller or device.

• If the M2A will be wired into a Modbus network, see “Chapter 8: RS-485 Modbus

Output” on page 51.

Max Distance to Controller w/

16 Gauge Wire

Max Distance to Controller

w/14 Gauge Wire

M2A Transmitter Operator’s Manual 66

24 VDC

Power Supply

24 V DC +

24 VDC -

See Figure 31 below for field wiring connections to the M2A.

Alarm Device

Power

4-20mA In (S)

(24 VD C) -

Controller

(PLC, DCS)

- S +

FAIL

C NC NO

See

Detector

Wiring

See

Modbus

Wiring

LEL

R W G B

RS 485 PWR/SIG

A B C

C NC NO

ALARM 1

ALARM 2

Figure 31: PLC and DCS Device Wiring

Fail Alarm Device

Alarm 1 Alarm Devic

Alarm 2 Alarm Devic

Typical Alarm WiringShown

67 M2A Trans mitte r Op erato r’ s Manu al

Appendix C: Function Code 16 Registers

The M2A suppo rts Function Code 16 that allows writing to the M2A. There are 21 registers in this Function Code.

Register 7 is the alarm 2 set point. Value must be an integer. Any decimals are omitted. The decimal point location is the same as specified in Register 1 of Function Code 03.

M2A Transmitter Operator’s Manual 68

Register 13 is the zero suppression. Toxics and LEL: 0%-6% Full Scale Oxygen: 0%-0.7% Oxygen Value must be an integer. Any decimals are omitted.

Register 19 is for clearing change flags. When parameters are changed at the M2A, a flag is raised at the controller. This register can be used to clear those flags.

Table 18: Register 19, Clear Change Flags

Bit(s) Value & Field

[15:2] Unused [1] Write “1” to this bit to clear “Gas Type Changed” flag [0] Write “1” to this bit to clear “Configuration Changed” flag

69 M2A Trans mitte r Op erato r’ s Manu al

M2A Transmitter Operator’s Manual 70

RKI Instruments M2A User Manual

Specifications and Main Features

Frequently Asked Questions

User Manual