Detcon DM-100 User Manual

Model DM-100

DM-100 Toxic Gas Sensors

DM-100 O2 Deficiency Sensors

DETCON, INC.

DM-100

GAS

H2S

RANGE

100 PPM

Operator’s Installation and Instruction Manual

Covers all Model DM-100 Sensors

DETCON, Inc.

4055 Technology Forest Blvd,

The Woodlands, Texas 77381

Ph.281.367.4100 / Fax [phone]

www.detcon.com

January 30, 2014 • Document #3604 • Revision 3.3

This page left intentionally blank

Model DM-100

Model DM-100 ii

Model DM-100

Table of Contents

1. Introduction ..................................................................................................................................................1

1.1 Description.......................................................................................................................................... 1

1.2 Modular Mechanical Design............................................................................................................... 2

1.3 Model 100 Standard Terminal Board (Optional)................................................................................ 4

1.4 DM-100 Display Terminal Board (Optional)..................................................................................... 4

1.5 DM-100 Series Display (Optional)..................................................................................................... 5

1.6 Wireless Transceiver and Battery Pack (Optional)............................................................................. 5

2. Installation....................................................................................................................................................6

2.1 Hazardous Locations Installation Guidelines for Safe Use................................................................. 6

2.2 Sensor Placement................................................................................................................................ 7

2.3 Sensor Contaminants and Interference ............................................................................................... 8

2.4 Sensor Mounting................................................................................................................................. 8

2.5 Electrical Installation.......................................................................................................................... 9

2.6 Field Wiring...................................................................................................................................... 10

2.6.1 DM-100 Display Terminal Board Settings................................................................................... 11

2.7 Initial Start Up................................................................................................................................... 11

2.7.1 Toxic Gas Sensors........................................................................................................................ 11

2.7.2 O2Deficiency Sensors.................................................................................................................. 13

3. Operation....................................................................................................................................................14

3.1 Normal Operation............................................................................................................................. 14

3.2 Auto Span Level Adjustment............................................................................................................ 14

3.3 Calibration......................................................................................................................................... 15

3.3.1 Zero Calibration............................................................................................................................ 15

3.3.2 Span Calibration........................................................................................................................... 17

3.4 Fault Diagnostic/Failsafe Feature..................................................................................................... 19

4. Service and Maintenance............................................................................................................................20

4.1 Replacement of Plug-in Sensor......................................................................................................... 20

4.2 Replacement of ITM......................................................................................................................... 21

4.3 Replacement of the Model 100 Terminal Board............................................................................... 21

5. Troubleshooting Guide...............................................................................................................................23

5.1 Smart Display Error Codes............................................................................................................... 25

6. Customer Support and Service Policy........................................................................................................26

7. DM-100 Sensor Warranty ..........................................................................................................................27

8. Appendix ....................................................................................................................................................28

8.1 Specifications.................................................................................................................................... 28

8.2 Sensor Specific Data......................................................................................................................... 29

8.3 Interference Table............................................................................................................................. 31

8.4 Proper Application and Maintenance of Acrylonitrile Sensor.......................................................... 37

8.5 Intrinsically Safe Installation Guidelines, Control Drawing #3993.................................................. 38

8.6 Spare Parts, Sensor Accessories, Calibration Equipment................................................................. 39

8.7 Revision Log..................................................................................................................................... 40

Model DM-100 iii

Model DM-100

Table of Figures

Figure 1 Sensor Assembly with Optional J-Box and LED Display..................................................................... 1

Figure 2 Construction of Electrochemical Toxic Sensor...................................................................................... 1

Figure 3 Construction of Galvanic Cell................................................................................................................ 2

Figure 4 Sensor Assembly Breakaway................................................................................................................. 2

Figure 5 Functional Block Diagram..................................................................................................................... 3

Figure 6 Plug-in Sensor........................................................................................................................................ 3

Figure 7 DM Standard Terminal Board................................................................................................................ 4

Figure 8 Model 100 Display Terminal Board ...................................................................................................... 4

Figure 9 Model 100 Series Display...................................................................................................................... 5

Figure 10 Approval Label .................................................................................................................................... 6

Figure 11 Typical DM-100 Sensor Assembly and Mounting Dimensions.......................................................... 9

Figure 12 Typical Installation ............................................................................................................................ 10

Figure 13 Magnetic Programming Tool............................................................................................................. 14

Figure 14 Magnetic Programming Switches...................................................................................................... 14

Figure 15 Control Drawing #3993 .....................................................................................................................38

List of Tables

Table 1 Terminal Board Connectors.................................................................................................................... 5

Table 2 Model 100 Terminal Board Jumper ...................................................................................................... 11

Table 3 Sensor Specific Data .............................................................................................................................29

Table 4 Interfering Gases................................................................................................................................... 31

Table 5 Cross Interference Table .......................................................................................................................32

Shipping Address: 4055 Technology Forest Blvd, The Woodlands, Texas 77381

Mailing Address: P.O. Box 8067, The Woodlands Texas 77387-8067

Phone: [phone]• Fax: [phone] • www.detcon.com • [e-mail]

Model DM-100 iv

Model DM-100

1. Introduction

1.1 Description

Detcon Model DM-100 toxic gas and O2deficiency sensors are non-intrusive 4-20mA loop powered sensors
designed to detect and monitor a wide range of toxic gases in the air. Ranges of detection for toxic gases are 0­1ppm up to 0-10,000ppm; typical ranges of detection are 0-10ppm, 0-25ppm, 0-50ppm and 0-100ppm. Ranges
for O2deficiency are 0-1% up to 0-25% by volume.

The basic sensor assembly consists of an electrochemical fuel cell mounted in Intrinsically Safe stainless steel
housing and includes a Splash Guard Cal Adapter. Optionally, the sensor can be installed on an explosion
proof junction box with a Model 100 Terminal Board and may include a Model 100 Loop Powered LED
display. Other options are available, contact Detcon for more information.

Model 100

DETCON,INC.

DM-100

H2S

100PPM

Figure 1 Sensor Assembly with Optional J-Box and LED Display

Electrochemical Sensor Technology

The DM-100 toxic gas sensors are based on electrochemical cells. Each cell consists of three electrodes
embedded in an electrolyte solution all housed beneath a diffusion membrane. Sensitivity to specific target
gases is achieved by varying composition of any combination of the sensor components. Good specificity is
achieved in each sensor type. The cells are diffusion limited via small capillary barriers resulting in a long
service life of up to three or more years. The electrochemical cell is packaged as a field replaceable plug-in
sensor.

Figure 2 Construction of Electrochemical Toxic Sensor

DM-100 Instruction Manual Rev. 3.3 Page 1 of 40

Model DM-100

The DM-100 O2deficiency sensor technology is a two electrode galvanic metal air battery type cell, which is
housed as a field replaceable intelligent plug-in sensor. The cell is diffusion limited and functions as a direct
current generator proportional to the amount of oxygen adsorption. The sensors are temperature compensated
and show good accuracy and stability over the operating temperature range of -20° to 50°C (-4° to +122° F).
The sensor is warranted for two years and has an expected service life of up to 2.5 years in ambient air at

20.9% oxygen.

Figure 3 Construction of Galvanic Cell

1.2 Modular Mechanical Design

The Model DM-100 Sensor Assembly is completely modular and is made up of four parts (Figure 4):

1. DM-100 Intelligent Transmitter Module (ITM)

2. Intelligent Plug-in Sensor (varies by gas type and range)

3. 100 Series Bottom Housing Assembly (H2S assemblies use 100 Series Bottom Housing Assembly
with Integral Filter)

4. Splash Guard.

100 Series Bottom

Housing Assembly

Splash Guard

Housing Bottom

Locking Screw

O-Ring

Plug-in
Replaceable
Sensor

Programming

100 PPM

H2S

Magnetic

Switches

3

" NPT Locking Nut

4

DM-100

DETCON, INC.

Intelligent Transmitter Module (ITM)
Micro-processor controlled circuit
encapsulated in an Explosion proof
housing.

Interconnect

Wires

Figure 4 Sensor Assembly Breakaway

NOTE

DM-100 Instruction Manual Rev. 3.3 Page 2 of 40

All metal components are constructed from electro polished 316 Stainless Steel in order to
maximize corrosion resistance in harsh environments.

Model DM-100

RS-485

Safe Barrier

DM-100 Intelligent Transmitter Module

The Transmitter Module is a microprocessor-based package that is attached to the explosion proof junction
box.

Circuit functions include;

 an intrinsically safe barrier,
 on-board power supply,
 microprocessor,
 magnetic programming switches,
 and a linear 4-20mA DC output.

Magnetic program switches located on either side of the ITM are activated via a hand-held magnetic
programming tool, thus allowing non-intrusive operator interface with the Transmitter Module. Electrical
classifications are Class I, Division 1, Groups A, B, C, and D.

Intrinsically

RS-485 Port

Analog 4-20mAOut

Power In

Plug-In

Sensor

Micro-

Processor

4-20mA

Loop

Power

I/O

Circuit

Protection

Figure 5 Functional Block Diagram

Field Replaceable Sensor

The Detcon family of electrochemical gas sensors is field proven, plug-in sensors with over-sized gold-plated
connections that eliminate corrosion problems. The sensor can be accessed and replaced in the field easily by

releasing the locking screw and unthreading the Splash Guard Adapter. Detconꞌs family of toxic sensors has a

long shelf life and is supported by an industry-leading warranty (Section 7).

Figure 6 Plug-in Sensor

DM-100 Instruction Manual Rev. 3.3 Page 3 of 40

Model DM-100

1.3 Model 100 Standard Terminal Board (Optional)

If the sensor is ordered with an explosion proof condulet/junction box, the sensor will come with the Model
100 Standard Terminal Board mounted in the J-Box (Figure 7). This terminal board affords the user easy plug­in connectors for use in wiring the unit during installation, and convenient test points for measuring the
milliamp (mA) output.

Customer

Wiring

Figure 7 DM Standard Terminal Board

V+
mA

RED

Sensor Wiring

WHITE

GREEN

BLUE

The standard terminal board provides an easy Digital Volt Meter (DVM) connection for reading the mA output

from the sensor. Two test points (TP1 and TP2) provide a connection across a 10Ω resistor that develops a

10mV voltage drop per 1mA output. Thus a reading of 40mV on a DVM equals 4mA of current. This is an
alternative method to reading the mA output of the sensor for assemblies that do not include the DM-100
Series Display option. Refer to Section 2.6, Field Wiring for more information about the setup of the DM-100
Terminal Board.

1.4 DM-100 Display Terminal Board (Optional)

If the unit is ordered with the optional display or a battery pack (wireless configurations) the unit comes with
the DM-100 Display Terminal Board mounted in the J-Box (Figure 8).

Customer Wiring

mA

WIRELESS
PROGRAM

J2

J7

J6

POWER IN
( SOLAR)

AIN2MAGND

24V

SENSOR

POWER

PWR

A

B

GND

MODBUS OUT
( WIRELESS)

B

A

24V

GND

MODBUS IN

PROGRAM

WIRELESS

W/BK

W/BN

W/BU

W/GN

W/V

AIN1

J8

SW2

24V

GND

J1

J4

SW1

A

B

J5

TERM

GND

PWR

L9

SCL

DISPLAY

JP1

SP1

SP2

SDA

WHITE

BLACK

BLUE

RED

Figure 8 Model 100 Display Terminal Board

DM-100 Instruction Manual Rev. 3.3 Page 4 of 40

Model DM-100

JP1

This terminal board includes connectors for the following:

Table 1 Terminal Board Connectors

Terminal Connector Purpose

J1 4-Pin Connector Modbus Out (Wireless Transceiver Option)
J2 6-Pin Header Wireless Transceiver Programming Header
J3 6-Beau Connector Battery operation or display interface dependent on sensor configuration
J4 4-Pin Connector Modbus In
J5 6-Pin Connector Display interface with battery/wireless configurations
J6 4-Pin Connector Sensor connections
J7 4-Pin Connector Auxiliary power in and mA out
J8 6-Pin Connector Wireless Transceiver
J9 5-Pin Header Terminal Board Programming

The Model 100 Display Terminal Board does not provide test points for measuring the milliamp (mA) output.
The mA output is available at J7.

NOTE

Install JP1 jumper on pins 1 and 2 if a battery pack is used. Install
battery is not used.

on pins 2 and 3 if

1.5 DM-100 Series Display (Optional)

The DM-100 Series Display is a 4-digit LED display that provides a direct display of the sensor readings. In
units that are ordered with the optional display, the display is mounted directly onto the J3 Beau connector of
the Display Terminal Board so the display can be easily seen through the J-box window. The display
automatically identifies the ITM, the sensor type, and range. This factory installed option must be ordered with
the sensor assembly.

Figure 9 Model 100 Series Display

1.6 Wireless Transceiver and Battery Pack (Optional)

The DM-100 has the option to operate on a wireless network with the addition of a wireless transceiver and
battery pack. These options allow the sensor to be remotely mounted without the need for cables. These
options are factory installed. Contact Detcon for more information on these options.

DM-100 Instruction Manual Rev. 3.3 Page 5 of 40

Model DM-100

2. Installation

2.1 Hazardous Locations Installation Guidelines for Safe Use

1. Install the sensor only in areas with classifications matching the approval label. Follow all warnings
listed on the label.

Figure 10 Approval Label

2. For intrinsically safe Ex ia installations, follow the intrinsically safe installation guidelines shown in
control drawing #3993, Section 8.5.

3. For non-intrinsically safe Ex mb [ib] installations, ensure that the sensor is properly threaded into a
suitable explosion-proof rated junction box with a downward pointing female3/4" NPT threaded
connection. The sensor should be threaded at least 5 full turns until tight, with the locking screw
facing forward. Avoid use of Teflon Tape, or any type of non-conductive pipe thread coating on the
NPT threaded connection.

4. A good ground connection should be verified between the sensor’s metal enclosure and the junction
box. If a good ground connection is not made, the sensor can be grounded to the junction box using
the sensor’s external ground lug. Verify a good ground connection between the junction box and earth
ground.

5. Proper precautions should be taken during installation and maintenance to avoid the build-up of static
charge on the plastic components of the sensor (Splash Guard and Splash Guard adapter).

6. All input circuits of the DM-100 must be connected to current limiting devices (e.g. Fuses of 1500
amp breaking capacity) to ensure that the maximum input current does not exceed 62mA.

7. Do not substitute components. Substitution of components may impair the intrinsic safety rating.

8. Do not operate the sensor outside of the stated operating temperature limits.

9. Do not operate the sensor outside the stated operating limits for voltage supply.

10. These sensors meet ATEX standards EN60079-0, EN60079-18 and EN60079-11.

11. These sensors have a maximum safe location voltage of Um=60V.

12. These sensors pass dielectric strength of 500VRMS between circuit and enclosure for a minimum of 1
minute at a maximum test current of 5mA.

DM-100 Instruction Manual Rev. 3.3 Page 6 of 40

Model DM-100

13. The DM-100 may be used as an oxygen deficiency sensor; the DM-100 must not be used for detecting
oxygen concentrations expected to be greater than 21%.

14. The DM-100 must only use gas sensor cell models 371-xxxxxx-xxx (Table 5, Section 8.1). No other
gas sensor cells shall be used.

2.2 Sensor Placement

Sensor location is critical to the overall safe performance of the product. Five factors play an important role in
selection of sensor locations:

1. Density of the gas to be detected

2. Most probable leak sources within the industrial process

3. Ventilation or prevailing wind conditions

4. Personnel exposure

5. Maintenance access

Density

Placement of sensors relative to the density of the target gas is such that sensors for the detection of heavier
than air gases should be located within 4 feet of grade as these heavy gases will tend to settle in low lying
areas. For gases lighter than air, sensor placement should be 4 to 8 feet above grade in open areas or in pitched
areas of enclosed spaces.

Leak Sources

The most probable leak sources within an industrial process include flanges, valves, and tubing connections of
the sealed type where seals may either fail or wear. Other leak sources are best determined by facility
engineers with experience in similar processes.

Ventilation

Normal ventilation or prevailing wind conditions can dictate efficient location of gas sensors in a manner
where the migration of gas clouds is quickly detected.

Personnel Exposure

The undetected migration of gas clouds should not be allowed to approach concentrated personnel areas such
as control rooms, maintenance or warehouse buildings. A more general and applicable thought toward
selecting sensor location is combining leak source and perimeter protection in the best possible configuration.

Maintenance Access

Consideration should be given to providing easy access for maintenance personnel and the consequences of
close proximity to contaminants that may foul the sensor prematurely.

NOTE

In all installations the gas sensor should point straight down (Figure 12). Improper sensor
orientation may result in false readings and permanent sensor damage.

Additional Placement Considerations

The sensor should not be positioned where it may be sprayed or coated with surface contaminating substances.
Painting sensor assemblies is prohibited.

DM-100 Instruction Manual Rev. 3.3 Page 7 of 40

Model DM-100

Although the sensor is designed to be RFI resistant, it should not be mounted in close proximity to high­powered radio transmitters or similar RFI generating equipment.

When possible mount in an area void of high wind, accumulating dust, rain, or splashing from hose spray,
direct steam releases, and continuous vibration. If the sensor cannot be mounted away from these conditions
then ensure the Detcon Harsh Location Dust Guard accessory is used.

Do not mount in locations where temperatures will exceed the operating temperature limits of the sensor.
Where direct sunlight leads to exceeding the high temperature-operating limit, use a sunshade to help reduce
temperature.

2.3 Sensor Contaminants and Interference

Electrochemical toxic gas may be adversely affected by exposure to other airborne gases. Depending on the
cross-sensitivity relationship, there may be a positive or negative impact on the reading.

The most commonly present gases that potentially cause interference problems are listed in Table 4,
Interfering Gases and Table 5, Cross Interference Table (Section 8.3, Interference Table).

The presence of cross-interference gases in an area does not preclude the use of this sensor technology. The
sensor could experience a false high or false low reading should exposure occur.

Cross-Interference Data Table

The gases typically found in industrial environments that may cause a cross-interference response on Detcon
toxic gas sensors are listed in Table 5 (Section 8.3, Interference Table). Review Table 5 for the correct gas and
then scan across the list for possible interference gases. Determine the magnitude of cross-interference that
may occur.

2.4 Sensor Mounting

The DM-100 should be vertically oriented so that the sensor points straight downward. The explosion-proof
enclosure or junction box is typically mounted on a wall or pole (Figure 11). Detcon provides a selection of
standard junction boxes in both Aluminum and Stainless Steel.

If wall mounting without a mounting plate, make sure to use at least 0.5" spacers

NOTE

NOTE

underneath the J-Box’s1/4" mounting holes to move the wireless sensor assembly away
from the wall and allow access clearance to the sensor assembly.

Do not use Teflon Tape or any other type of Pipe Thread material on the3/4" threads unless
the sensor is mounted in a severe or harsh environment. Metal-on-metal contact must be
maintained to provide a solid electrical ground path. If Teflon Tape is used the Sensor must
be externally grounded using a ground strap.

DM-100 Instruction Manual Rev. 3.3 Page 8 of 40

Model DM-100

When mounting on a pole, secure the Junction Box to a suitable mounting plate and attach the mounting plate
to the pole using U-Bolts. (Pole-Mounting brackets for Detcon Junction Box’s are available separately.)

1

4

13.75" Typ.

" mounting holes

6.1"

5.5"

DETCON,INC.

DM-100

H2S

100 PPM

3

NPT Ports

4

8-32 tapped
ground point

9.625" Typ.

Use spacersto move

sensor assembly away

from wallat least 0.5".

ITM Assembly

Splash GuardAdapter

4.35"

Spacer

Wall (or other

mounting surface)

2"

Splash Guard

Figure 11 Typical DM-100 Sensor Assembly and Mounting Dimensions

2.5 Electrical Installation

The Sensor Assembly should be installed in accordance with local electrical codes. The sensor assemblies are
CSA/NRTL approved (US and Canada) for Class I, Division 1, Groups A, B, C, & D area classifications, and
are ATEX Approved for Class I, Zone 1, Group IIC area classifications.

Proper electrical installation of the gas sensor is critical for conformance to Electrical Codes and to avoid
damage due to water leakage. Refer to Figure 8 and Figure 12 for proper electrical installation.

NOTE

In Figure 12, the drain allows H2O condensation inside the conduit run to safely drain away from the sensor
assembly. The electrical seal fitting is required to meet the National Electrical Code per NEC Article 500-3d
(or Canadian Electrical Code Handbook, Part 1, Section 18-154). Requirements for locations of electrical seals
are covered under NEC Article 501-5. Electrical seals act as a secondary seal to prevent water from entering
the wiring terminal enclosure. However, they are not designed to provide an absolute watertight seal,
especially when used in the vertical orientation.

If a conduit run exits the secondary port, repeat the installation technique shown in
Figure 12.

DM-100 Instruction Manual Rev. 3.3 Page 9 of 40

Model DM-100

NOTE

NOTE

A conduit seal is typically required to be located within 18" of the J-Box and Sensor
Assembly. Crouse Hinds type EYS2, EYD2 or equivalent are suitable for this purpose.

The Detcon Warranty does not cover water damage resulting from water leaking into the
enclosure.

Conduit

"T"

Drain

EYS Seal Fitting

Model1 00

DETCON,INC.

DM-100

100PPM

H2S

Figure 12 Typical Installation

Any unused ports should be blocked with suitable3/4" male NPT plugs. Detcon supplies one

3

NOTE

/4" NPT male plug with each J-box enclosure. If connections are other than3/4" NPT, use

an appropriate male plug of like construction material.

2.6 Field Wiring

Detcon Model DM-100 sensor assemblies require two conductor connections between power supplies and host
electronic controller’s 4-20mA input. Wiring designations are PWR and mA (sensor signal).

Shielded cable is required for installations where cable trays or conduit runs include high

NOTE

NOTE

Terminal Connections – with Junction Box Option

CAUTION

voltage lines or other possible sources of induced interference. Separate conduit runs are
highly recommended in these cases.

The supply of power should be from an isolated source with over-current protection.

Do not apply System power to the sensor until all wiring is properly terminated.
Refer to Section 2.7, Initial Start Up.

DM-100 Instruction Manual Rev. 3.3 Page 10 of 40