Detcon CXT-DM User Manual

DETCON, Inc.

May 29, 2014 • Document # 3804 • Revision 1.6

Model CXT-DM

CXT-DM Toxic Gas Sensors

CXT-DM O2 Deficiency Sensors

Operator’s Installation and Instruction Manual

Covers all Model CXT-DM Sensors

4055 Technology Forest Blvd, Suite 100

The Woodlands, Texas 77381

Ph.281.367.4100 / Fax 281.298.2868

www.detcon.com

Model CXT-DM

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Model CXT-DM ii

Model CXT-DM

Table of Figur es

Figure 1 Sensor Assembly with Optional J-Box and Smart Rechargeable Battery Pack ..................................... 1

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

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

Figure 4 Sensor Assembly Breakaway ................................................................................................................. 3

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

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

Figure 7 Smart Battery Pack ................................................................................................................................ 5

Figure 8 Quad Battery Charger ............................................................................................................................ 5

Figure 9 Tri C Lithium Battery Holder ................................................................................................................ 6

Figure 10 Approval Label .................................................................................................................................... 7

Figure 11 CXT-DM Sensor with Smart Battery Pack Mounting Dimensions ................................................... 10

Figure 12 CXT-DM Sensor with Lithium Battery Pack..................................................................................... 11

Figure 13 Terminal Interconnect for Smart Battery Pack .................................................................................. 13

Figure 14 Magnetic Programming Tool

Figure 15 Magnetic Programming Switches ...................................................................................................... 16

Figure 16 Software flow chart ............................................................................................................................ 18

Figure 17 Modbus™ Frame Format ................................................................................................................... 27

Figure 18 Battery Orientation Diagram .............................................................................................................. 34

Figure 19 Sensor Cell and ITM Mating ............................................................................................................. 35

............................................................................................................. 16

List of Tables

Table 1 Exception Codes .................................................................................................................................... 28

Table 2 CXT-DM Register Map......................................................................................................................... 29

Table 3 Sensor Specific Data ............................................................................................................................. 42

Table 4 Interfering Gases ................................................................................................................................... 44

Table 5 Cross Interference Table ....................................................................................................................... 45

Model CXT-DM iv

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

Model CXT-DM

1. Introduction

1.1 Description

Detcon Compact Wireless Sensor Model CXT-DM toxic gas and O wireless sensors designed to detect and monitor a wide range of toxic gases in air. The unit is designed to work as part of a wireless network of gas sensors and communication is performed via a built-in RF transceiver. Ranges of detection for toxic gases are from 0-1ppm up to 0-10,000ppm; typical ranges of detection are 0-10ppm, 0-25ppm, 0-50ppm and 0-100ppm. Ranges for O by volume. The basic sensor assembly consists of an electrochemical sensor 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 choice of battery pack options making operation fully independent of outside cabling. Other options are available, contact Detcon for more information.

deficiency sensors are non-intrusive

2

deficiency are 0-1% up to 0-25%

2

Figure 1 Sensor Assembly with Optional J-Box and Smart Rechargeable Battery Pack

Electrochemical Sensor Technology

The 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.

CXT-DM Instruction Ma nu al Rev. 1.6 Page 1 of 52

Model CXT-DM

Figure 2 Construction of Electrochemical Toxic Sensor

The O

deficiency sensor technology is a two electrode galvanic metal air battery type cell, which is housed as

2

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° Fahrenheit). 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 Design

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

1) CXT-DM Intelligent Transmitter Modu le (I TM)

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

3) CXT Series Bottom Housing

4) Splash Guard.

CXT-DM Instruction Ma nu al Rev. 1.6 Page 2 of 52

Model CXT-DM

CXT / 700 DM Series

Bottom Housing Assembly

Plug-in

Replaceable

Sensor

Intelligent Transmitter Module (ITM)

Micro-processor controlled circuit

encapsulated in an Explosion proof

housing.

Magnetic Programming Switches

Splash Guard

3

4

" NPT Locking Nut

Ferrite Bead

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

Accessory connections

Antenna Power In

Wireless

Power

Intrinsically Safe Barrier

Figure 4 Sensor Assembly Breakaway

1.2.1 CXT-DM 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, Div 1, Groups B, C, and D.

Plug-In

Sensor

Micro-

Processor

I/O

Circuit

Protection

supplies

Figure 5 Functional Block Diagram

1.2.2 Field Replaceable Sensor

The Detcon family of electrochemical gas sensor 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 Splashguard Adapter Assembly. Detcon’s family of toxic sensors has a long shelf life and is supported by an industry-leading warranty.

CXT-DM Instruction Ma nu al Rev. 1.6 Page 3 of 52

Figure 6 Plug-in Sens or

Model CXT-DM

NOTE: If there are multiple Modbus™ networks in the same vicinity each system must reside on a different RF Channel to keep data from one appearing on the other.

1.3 CXT Wireless Network

The CXT-DM sensor utilizes a transceiver radio, based upon the IEEE 802.15.4 standard. The transceiver operates at 2.4 GHz using DSSS encoding for robustness. DSSS was initially used by the military to resist jamming but later was widely adopted for wireless implementations since it was robust in noisy environments. DSSS transmits data across a wider frequency range than the actual frequency range required for the information. This operation minimizes cross talk and interference from other transceivers and is less susceptible to noise from other sources.

The IEEE 802.15.4 defines 16 separate RF Channels that can be used in the 2.4 GHz range. The default channel is 1 but can be changed if there is RF interference or if there is an existing network using that channel. Transceivers will only respond to other transceivers with the same RF Channel.

The 802.15.4 standard also implements a mesh network allowing any CXT-DM transceiver to relay or repeat data between adjacent neighbors. This makes the network very robust and provides the following immediate benefits:

• Allows re-routing of data in case of loss of a transceiver

• Allows re-routing around wireless obstacles

• Longer distances between trans ceiv er s becaus e data can “hop” from one transceiver to the next

• Included in sensor, controller and alarm station transceivers

• CXT-DM transceivers can be deployed with less concern about physical location

1.4 Battery Pack Options

The CXT-DM can be powered by an optional battery pack that enables it to be remotely mounted without the need for external cabling. Detcon offers several battery pack options. These options are factory installed. Contact Detcon for more information on these options.

1.4.1 Detcon’s Smart Battery Pack

The Detcon’s plug-in Smart Battery Pack provides an output of 12VDC (See Figure 7). The CXT-DM monitors the battery pack for remaining battery life. The battery pack consists of rechargeable Lithium-Ion batteries and is equipped with integrated safety electronics that include fuel gauge, voltage, current and temperature monitoring circuits. This “smart” circuitry continuously monitors the battery’s condition and reports critical status information to the wireless transceiver via the Modbus™ registers. The battery pack is designed to plug onto an 8-pin Beau connector on a Terminal Board that the sensor is connected to. The battery Pack and Terminal Board are housed in the Detcon Aluminum Condulet to protect them from exposure to outside elements and still provide Class I Div 1, C, and D approvals. Operating periods before recharge will vary based on sensor attached, but can be as long as 5-6 months and battery life can be up to 5 years before battery pack replacement is required. Improper use of the battery pack may be hazardous to personnel or the environment and will void the warranty.

CXT-DM Instruction Ma nu al Rev. 1.6 Page 4 of 52

Model CXT-DM

Figure 7 Smart Battery Pack

Quad Battery Charger (Optional)

Detcon’s Smart Battery Pack can be charged as needed using Detcon’s optional Quad Battery Charger which can charge up to four battery packs at one time. The Quad Battery Charger comes with a plug-in AC/DC adapter that plugs into a standard 100-240VAC outlet for power. The DC end of the adapter plugs into the DC power jack of the charger providing 24VDC. The Quad Battery Charger has four charging ports, each with 8pin Beau connectors for battery pack connection. The ports and connectors are keyed to prevent incorrect positioning and connection. Each port has its own “FAULT” LED indicator and “CHARGE” LED indicator and will display either a red light or green light depending on the status of each battery being charged. Charging times will vary depending on the charge state of each battery pack, but a full charge of a depleted battery pack can take up to 24 hours.

Figure 8 Quad Battery Charger

1.4.2 Tri-C Lithium Battery Pack

The Tri-C Lithium Battery Pack (Figure 9) contains three 3.6V Lithium Primary C size batteries which are not re-chargeable. This battery pack offers a more compact size, and provides the unit with 10.8 volts. The batteries are contained in a battery holder mounted in Detconꞌs stainless steel explosion proof mini-condulet. This option offers a smaller foot print, but provides less run time than Detcon’s Smart Battery Pack. The CXT-

CXT-DM Instruction Ma nu al Rev. 1.6 Page 5 of 52

Model CXT-DM

IR sensors will operate up to 60 days before battery replacement is needed. The addition of Detconꞌs Stainless

Steel Mini Condulet provides Class I Div 1, Group B, C, and D ratings.

Figure 9 Tri C Lithium Battery Holder

CXT-DM Instruction Ma nu al Rev. 1.6 Page 6 of 52

Model CXT-DM

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. Do not remove the junction box cover while in the classified are unless it is conformed the there is no

explosive gas levels in the area.

3. 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.

4. Proper precautions should be taken during installing and maintenance to avoid the build-up of static

charge on the plastic components of the sensor (Splash Guard and Antenna Dome Cover) Wipe with damp cloth on plastic components to avoid static discharge.

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

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

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

8. These sensors meet ATEX standards EN60079-0:2012. EN60079-1:2007 and EN60079-11:2012.

9. These sensors have a maximum safe location voltage of Um=30V.

10. These sensors pass dielectric strength of 500VRMS between circuit and enclosure for a minimum of 1

minute at a maximum test current of 5mA.

11. The CXT-DM may be used as an oxygen deficiency sensor; the CXT-DM must not be used for

detecting oxygen concentrations expected to be greater than 21%

12. The CXT-DM must only use gas sensor cell model 371-xxxx00-yyy. No other gas sensor shall be

used.

13. The CXT-DM is only to be used with Detcon P/N 360-026500-000 batteries (Tadiran Model TL-

5920). The battery holder utilizes three of these batteries in series to operate the sensor.

WARNING:

CXT-DM Instruction Ma nu al Rev. 1.6 Page 7 of 52

CSA certification does not include wireless communica tion or Modbus used for combustible gas performance.the wire less communication or M odbus may only be used for dat a collection or record keeping with regard to combustible gas detection. Gas indication and alarm functions for performance are only permitted locally by the detector.

Model CXT-DM

NOTE: In all installations the gas sensor should point straight down (refer to Figure 11).

Improper sensor orientation may result in false readings and permanent sensor damage.

2.2 Sensor Placement

Selection of sensor location is critical to the overall safe performance of the product. Six 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) Placement of transmitting antenna (6) 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 4-8 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. Consideration should also be given to the consequences of close proximity to contaminants that may foul the sensor prematurely.

Placement of RF Antenna

Placement of the sensor should also have consideration made for line of sight RF Transmissions. The devices should be placed in a reasonable proximity to other devices in the network. Obstacles between CXT transceivers can impact RF line-of-sight and may result in communication problems. The CXT sensor should be in view of at least one other transceiver.

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.

CXT-DM Instruction Ma nu al Rev. 1.6 Page 8 of 52

Model CXT-DM

NOTE: If wall mounting without a mounting plate, make sure to use at least 0.5” spacers

move the sensor

assembly away from the wall and allow acc ess cleara nc e to the sens or assem bly .

NOTE: Do not use Teflon Tape or any other type of Pipe Thread material on the ¾” threads

externally grounded using a ground strap.

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 make sure 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 Cont aminants and Interference

Electrochemical toxic gas may be adversely affected by exposure to other airborne gases. Depending o n 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 I nterfe renc e Table (Refer to section 9.3 Interference Tab l e).

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

Cross-Interference Data T ab le

Table 5 Cross Interference Table (refer to Section 9.3 Interference Table) lists the gases typically found in industrial environments that may cause a cross-interference response on members of the Detcon family of toxic gas sensors. Review Table 5 in Section 9.3 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 CX T-DM 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 (See Figure 11). Detcon provides a selection of standard junction boxes in both Aluminum and Stainless Steel.

underneath the Detcon Aluminum Junction-Box’s 1/4” mounting holes to

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

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 Boxes are available separately.)

CXT-DM Instruction Ma nu al Rev. 1.6 Page 9 of 52

Model CXT-DM

8-32 tapped ground point

7.45"

3

4

NPT Port

9.5"

Wall

(or other

mounting surface)

Splash Guard Adapter

Splash Guard

ITM Assembly

23" Typ.

Use spacers to move

sensor assembly away

from wall at least 0.5".

Spacer

1

4

" mounting

holes

Spacer

5.5"

Figure 11 CXT-DM Sensor with Smart Battery Pack Mounting Dimensi ons

CXT-DM Instruction Ma nu al Rev. 1.6 Page 10 of 52

Model CXT-DM

6-32 tapped ground point

4.1"

3

4

NPT Port

3.64"

Ø0.4 X 0.475" mounting holes

Splash Guard Adapter

Splash Guard

ITM Assembly

3.45"

22"Typ.

Mini Condulet with Battery Holder and Batteries

Figure 12 CXT-DM Sensor with Lithium Battery Pack

2.5 Electrica l Installation

The CXT is designed to be battery operated, and normally will not have external cabling or wiring. If the sensor requires external wiring, the Sensor Assembly should be installed in accordance with local electrical

CXT-DM Instruction Ma nu al Rev. 1.6 Page 11 of 52

Model CXT-DM

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.

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

NOTE: Any unused ports should be blocked with suitable ¾” male NPT plugs. Detcon

NPT, use an appropriate male plug of like construction material.

The safety approvals require removing entire sensor assembly to a non-hazardous area before installing or changing out the batteries or battery pack.

codes. Proper electrical installation of the gas sensor is critical for conformance to electrical codes and to avoid damage due to water leakage.

If a conduit run exists a drain should be incorporated. The drain allows H

O condensation inside the conduit

2

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 also 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.

supplies one ¾” NPT male plug with each J-box enclosure. If connections are other than ¾”

If the Detcon CXT-DM was ordered with one of the optional Battery Packs, no wiring is necessary, although an external 24V source can be applied in some instances. If an external power source is incorporated, wire the external power source to the Terminal Interconnect board as prescribed in Figure 13.

CAUTION: Do not apply System power to the sensor until all wiring is properly terminated. Refer to Section 2.6 Initial Sta rt U p

Applying power to the unit

1. Remove the junction box cover.

2. If external power is to be applied to t he unit, connect incoming 24V to the terminal labeled “+” and 24V

Return to the terminal labeled “-”.

3. Install the batteries:

NOTE

a) For units utilizing the 12V Smart Battery Pack, plug the battery pack into the Terminal Board. If

the sensor has a power switch, power will not be applied until the switch is turned on. If the unit does not have a power switch, power will be applied, and the unit will proceed to power up (Section 2.6).

b) If the unit utilizes the “C” sized lithium 3.6V batteries and battery holder, install the batteries

being careful to install the batteries properly. If the sensor has a power switch, power will not be applied until the switch is turned on. If the unit does not have a power switch, power will be applied, and the unit will proceed to power up (Section 2.6).

4. Replace the junction box cover after Initial Start Up.

CXT-DM Instruction Ma nu al Rev. 1.6 Page 12 of 52

Model CXT-DM

Black

Wht/Blk

Wht/Brn

Red

To Sensor

24V Power

To External

Return

24VDC

+

-

NOTE: A 6-32 or 8-32 threaded exterior ground point is provided on most junction boxes for

rnal ground. If the Sensor Assembly is not mechanically grounded, an external ground

strap must be used to ensure that the sensor is electrically grounded.

NOTE: In normal operation the display will come on once every 10 seconds, will display the current reading for about 2 seconds, and will return to a blank display to conserve battery power.

Figure 13 Terminal Interconnect for Smart Battery Pack

an exte

2.6 Initial Start Up

2.6.1 Toxic Gas Sensors

Upon completion of all mechanical mounting, install the batteries; this will apply power to the unit. If the unit is equipped with the optional power switch, power is applied by pushing the switch. Observe the following normal conditions:

1. Upon power up the sensor will scroll “CXT-DM V##.##” and will then display the current reading for

about 5 seconds. A temporary upscale reading may occur as the sensor stabilizes. This upscale reading will decrease to “0” ppm within 1-2 minutes of power-up, assuming there is no gas in the area of the sensor. Sensors cells that use a bias voltage require a longer time to stabilize. This can vary between 1 and 24 hours depending on the sensor type and range. Biased sensors include NO, HCl, and VOC gases (ethylene oxide, ethylene, methanol, formaldehyde . . . etc.)

2. After the initial power up the sensor display will turn off. Thereafter the display will come on once

every 10 seconds and will display the current reading for about 2 seconds, and will return to a blank display to conserve battery power.

CXT-DM Instruction Ma nu al Rev. 1.6 Page 13 of 52

Model CXT-DM

NOTE: Calibration gas generators using perm tubes or electrochemical sources may be used in place of span gas cylinders.

NOTE: Wind Guard must be used when calibrating with the integral cal port to ensure proper calibration.

Initial Operational Tests

After a warm up period of 1 hour (or when zero has stabilized), the sensor should be checked to verify sensitivity to the target gas.

Material Requirements

• Detcon PN 613-120000-700 700 Series Splash Guard with integral Cal Port and Calibration Wind

Guard (P/N 943-000000-000) -OR-

• Detcon PN 943-000006-132 Threaded Calibration Adapter - OR -

• Detcon P/N 943-01747-T05 Teflon Calibration Adapter for highly reactive gases

• Detcon Span Gas; 50% of range target gas in balance N

or Air at fixed flow rate between 200-

2

500cc/min

1. Attach the calibration adapter to the Splashguard Adapter Assembly or connect tubing to integral cal

port. It is recommended that the Wind Guard (Detcon P/N 943-000000-000) is installed over the Splash Guard during calibration. Apply the test gas at a controlled flow rate of 200 - 500cc/min (500cc/min is the recommended flow). Observe that the ITM display increases to a level near that of the applied calibration gas value.

2. Remove test gas and observe that the display decreases to “0”.

3. If a calibration adapter was used during these tests, remove them from the unit, and re-install the

Splash Guard. If the wind guard was used, remove the wind guard.

Initial operational tests are complete. CXT-DM toxic gas sensors are factory calibrated prior to shipment, and should not require significant adjustment on start up. However, it is recommended that a complete calibration test and adjustment be performed 16 to 24 hours after power-up. Refer to zero and span calibration instructions in Section 3.3 Calibration.

2.6.2 O2 Deficiency Sensors

a) When first powered up the CXT-DM display should read close to 20.9%. b) The reading should stabilize within 1 to 2 minutes of power-up (assuming a ‘normal’ ambient O

concentration).

Initial Operational Tests

2

After a warm-up period of 5 minutes the sensor should be checked to verify response to O

Material Requirements

• -Detcon PN 613-120000-700 700 Series Splash Guard with integral Cal Port and with Wind Guard -

OR-

• -Detcon PN 943-000006-132 Threaded Calibration Adapter

• -Detcon Zero Gas: 100% N2 at fixed flow rate of 200-500cc/min

CXT-DM Instruction Ma nu al Rev. 1.6 Page 14 of 52

deficiency.

2

Model CXT-DM

NOTE: Wind Guard must be used when calibrating with the integral cal port to ensure proper calibration.

a) Attach the calibration adapter to the threaded sensor housing or connect tubing to the integral cal port.

Apply the test gas at a controlled flow rate of 200-500cc/min (500cc/min is the recommended flow). Observe that the ITM display decreases to a level near zero.

b) Remove test gas and calibration adapter. The ITM display should return to a reading of 20.9%.

Initial operational tests are complete. CXT-DM O

deficiency sensors are factory calibrated prior to shipment,

2

and should not require significant adjustment on start up. However, it is recommended that a complete calibration test and adjustment be performed 16 to 24 hours after power-up. Refer to zero and span calibration instructions in Section 3.3.

CXT-DM Instruction Ma nu al Rev. 1.6 Page 15 of 52

Model CXT-DM

NOTE: While in the Program Mode, if there is no magnetic switch interaction after 4 consecutive menu scrolls, the sensor will automatically revert to normal operating condition.

remain active.

Program Switch #1

LED Display

Program Switch #2

PGM2

SPAN

PGM1

ZERO

MODEL

CXT-DM

detcon inc.

H

2

S Sensor

3. Operation

The Operator Interface of the Model CXT Series gas sensors is accomplished via two internal magnetic switches located to either side of the LED display (see Figure 15). The two switches, labeled “PGM1” and “PGM2”, allow for complete calibration and configuration, thereby eliminating the need for area declassification or the use of hot permits.

Figure 14 Magnetic Programming Tool

The magnetic programming tool (Figure 14) is used to operate the magnetic switches. Switch action is defined as momentary contact (a swipe), a 3-second hold, and a 10-second hold. (Hold times are defined as the time from the point when the arrow-prompt ““appears. Swiping the magnet does not display the ““prompt.) For momentary contact use, the programming magnet is briefly held over a switch location, or swiped. For 3second hold, the programming magnet is held in place over the switch location for three seconds. For 10second hold, the programming magnet is held in place over the switch location for 10 seconds. The 3 and 10 second holds are generally used to enter calibration/program menus and save new data. The momentary contact is generally used to move between menu items and to modify set-point values. Arrows (“” and “”) are used on the LED display to indicate when the magnetic switches are activated. The location of “PGM1” and “PGM2” are shown in Figure 15.

Figure 15 Magnetic Programming Switches

While changing values inside menu items, if there is no magnet activity after 3-4 seconds the sensor will revert to the menu scroll. If the sensor is in Bump Test mode, the display will

CXT-DM Instruction Ma nu al Rev. 1.6 Page 16 of 52

Model CXT-DM

3.1 Operator Interface

The operating interface is menu-driven via the two magnetic program switches located under the target marks of the sensor housing. The two switches are referred to as “PGM1” and “PGM2”. The menu list consists of three menu items that include sub-menus:

Normal Operation

Concentration Reading is displayed once every 10 seconds.

Calibration Mode

AutoZero AutoSpan

Program Mode

View Sensor Status

Mp App ##.## CP App ##.## Rf App ##.##.## Rf Sw ##.## Modbus ID ## Serial Number ##.##.## RF Channel ## Network ID #### Range ### Autospan Level ## Tempcomp Level ## Last Cal ## Days Sensor Life ###%

Temperature ##C Set Detection Range Set Autospan Level Bump Test Set RF Channel Set Modbus ID

CXT-DM Instruction Ma nu al Rev. 1.6 Page 17 of 52

Model CXT-DM

dec

LEGEND: PGM1 - Program Switch Location #1

PGM2 - Program Switch Location #2 (S) - Momentary Swipe

(M) - Momentary hold of Magnet during text scroll until the ">" appears, then release (3) - 3 second hold from ">" prompt (10) - 10 second hold from ">" prompt Auto Time-out - 5 seconds

inc - Increase dec - Decrease #, ##, ### - numeric values

Serial N. ##.##.##

Temperature ##C

RF Channel ##

AutoZero

PGM1 (3)

PGM2 (10)

PGM2 (3)

RF App ##.##.##

CP App ##.##

RF SW ##.##

Modbus ID ####

inc

Auto Time-Out

View Sensor Status

PGM1/2 (3)

PGM1/2 (M)

MP App ##.##

PGM2 (S)

PGM1/2 (3)

PGM1 (S)

##

AutoTime-out

PGM1/2 (3)

PGM1/2 (M)

Set Detection Range

AutoSpan

Normal Operation

PGM1 (3)

Auto Time-OutAuto Time-Out

inc

PGM2 (S)

PGM1/2 (3)

PGM1 (S)

##

PGM1/2 (3)

PGM1/2 (M)

dec

PGM1/2 (3)

Bump Test Started

PGM1/2 (3)

PGM1/2 (M)

Bump Test

PGM1/2 (M)

Defaults Restored

PGM1/2 (3)

Restore Defaults

Auto Time-Out

dec

inc

PGM2 (S)

PGM1/2 (3)

PGM1 (S)

##

AutoTime-out

PGM1/2 (3)

PGM1/2 (M)

Set RF Channel

Auto Time-Out

inc

PGM2 (S)

PGM1/2 (3)

PGM1 (S)

##

PGM1/2 (3)

PGM1/2 (M)

Set Modbus ID

dec

Set Autospan Level

Network ID ##

Range ###

Last Cal ## Days

Sensor Life ###%

2 minute timeout

Software Flowchart

Figure 16 Software flow chart

3.2 Normal Operation

In normal operation, the ITM Display will be blank and will display the gas reading once every 10 seconds for about 2 seconds (normally appear as “0”). At any time swiping a magnet across either PGM1 or PGM2 will cause the ITM to display the range and gas type (i.e. “ppm H2S”). If the sensor is actively experiencing any diagnostic faults, a swipe of the magnet will cause the display to scroll the fault condition. Refer to Section 5 Service and Maintenance for more information on fault conditions.

3.3 Calibration Mode

CXT-DM Instruction Ma nu al Rev. 1.6 Page 18 of 52

Model CXT-DM

NOTE: The zero gas source may be zero air or N2 for toxic sensors, but must be pure N2 (99.99%) for O2 deficiency sensors

NOTE: The Calibration Wind Guard must be used when the Splashguard Adapter with

AutoZero calibration.

NOTE: Upon entering Calibration Mode, the Modbus™ Status Register bit 14 is set to signify

operation.

Zero and span calibration should be performed on a routine basis (quarterly minimum is advised) to ensure reliable performance. If a sensor has been exposed to any de-sensitizing gases, or to very high over-range combustible gas levels, re-calibration should be considered. Unless otherwise specified, span adjustment is recommended at 50% of the full scale range.

To enter Calibration Mode hold the magnet over PGM1 for 3 seconds. If the sensor is experiencing a fault condition the “” prompt will not appear until the fault(s) have been displayed. When the ITM enters Calibration Mode the display will scroll “Pgm1=Zero . . . Pgm2=Span” twice before returning to Normal Mode (about 5 seconds).

3.3.1 AutoZero

The AutoZero function is used to zero the sensor. AutoZero should be performed periodically or as required. AutoZero should be considered after periods of over-range target gas exposure. Local ambient air can be used to zero calibrate a toxic gas sensor as long as it can be confirmed that it contains no target or interference gasses. If this cannot be confirmed then a zero air or N zero calibration of the O

deficiency sensors.

2

Material Requirements:

• -Detcon PN 327-000000-000 MicroSafe™ Programming Magnet

• -Detcon PN 613-120000-700 Splash Guard with integral Cal Port and with Wind Guard. -OR-

• -Detcon PN 943-000006-132 Threaded Calibration Adapter

• -Detcon PN 942-001123-000 Zero Air cal gas (or use ambient air if no target gas is present).

• -Detcon P/N 942-640023-100 Nitrogen 99.99%

c ylinder should be used. Pure N2 must be used for

2

integral Cal Port is used. Failure to use the Calibration Wind Guard may result in an inaccurate

a) For toxic sensors, if the ambient air is known to contain no target gas content, then it can be used for zero

calibration. If a zero gas cal cylinder is going to be used, attach the calibration adapter and set flow rate of 200-500cc/min (500cc/min is the recommended flow rate) and let sensor purge for 1-2 minutes before executing the AutoZero. For O

deficiency sensors, apply N2 at a set flow rate of 500cc/min for 3-5

2

minutes before executing AutoZero.

b) From Normal Operation, enter Calibration Mode by holding the programming magnet over PGM1 for 3

seconds. Note, the “” prompt will show that the magnetic switch is activated during the 3 second hold period. The display will then scroll “Pgm1=Zero . . . Pgm2=Span”. Hold the pro gra mmin g magn et o ver PGM1 for 3 seconds once the “” prompt appears to execute AutoZero (or allow to timeout in 5 seconds if AutoZero is not desired).

the sensor is in-calibration mode. This bit will remain set until the program returns to normal

c) The ITM will display the following sequence of text messages as it proceeds through the AutoZero

sequence:

CXT-DM Instruction Ma nu al Rev. 1.6 Page 19 of 52

Model CXT-DM

NOTE: Before performing AutoSpan Calibration, verify that the AutoSpan level matches the span calibration gas concentration as described in Section 3.4.3 Set Autospan Level.

NOTE 1: Contact Detcon for Ordering Information on Span Gas cylinders.

NOTE 2: A target gas concentration of 50% of range is strongly recommended. This should

be supplied at a controlled flow rate of 200 to 500cc/min, with 500cc/min being the recommended flow rate. Other concentrations can be used if they fall within allowable levels of 5% to 100% of range.

NOTE 3: The Calibration Wind Guard must be used when the Splashguard Adapter with integral Cal Port is used. Failure to use the Calibration Wind Guard may result in an inaccurate AutoZero calibration.

NOTE 4: Ambient air should be used to calibrate O2 deficiency sensors as long as the oxygen concentration is confirmed to be 20.9%

NOTE 5: It is generally not advised to use other gasses to cross-calibrate for span. Crosscalibration by use of other gasses should be confirmed by Detcon.

Zero Cal . . . Setting Zero . . . Zero Saved ( each wil l scro ll twice)

d) Remove the zero gas and calibration adapter, if applicable.

3.3.2 AutoSpan

The AutoSpan function is used to span calibrate the sensor. AutoSpan should be performed periodically or as required. AutoSpan should be considered after periods of over-range target gas exposure. Unless otherwise specified, span adjustment is recommended at 50% of range. This function is called “AUTO SPAN”.

Material Requirements:

• Detcon PN 327-000000-000 MicroSafe™ Programming Magnet

• Detcon Splash Guard with integral Cal Port (PN 613-120000-700) and Calibration Wind Guard (PN

613-120000-700) - OR -

• Detcon PN 943-000006-132 Threaded Calibration Adapter

• Detcon Span Gas (See Detcon for Ordering Information). Recommended span gas is 50% of range

with target gas. Other suitable span gas sources containing the target gas in air or N acceptable.

balance are

2

CAUTION:

Verification that the calibration gas level setting matches the calibration span gas concentration is required before executing “AutoSpan” calibration. These two numbers must be equal.

AutoSpan consists of entering Calibration Mode and following the menu-displayed instructions. The display will ask for the application of span gas in a specific concentration. The applied gas concentration must be equal to the calibration gas level setting. The factory default setting and recommendation for span gas concentration is 50% of range. If a span gas containing the recommended concentration is not available, other concentrations may be used as long as they fall between 5% and 100% of range. However, any alternate span gas concentration value must be programmed via the “Set AutoSpan Level” menu before proceeding with AutoSpan calibration. Follow the instructions “a” through “e” below for AutoSpan calibration.

CXT-DM Instruction Ma nu al Rev. 1.6 Page 20 of 52

Model CXT-DM

NOTE: Upon entering Calibration Mode, the Modbus™ Status Register bit 14 is set to signify

operation.

NOTE: Ambient a ir should be used to calibrate O2 deficiency sensors as long as the oxygen concentration is confirmed to be 20.9%. There is no need to apply a flow of gas.

NOTE: When calibrating O2 deficiency sensors, there is no requirement to clear to <5% of range. The sensor will return to normal operation immediately after span adjustment.

NOTE 1: If the sensor fails the minimum signal change criteria, a “Range Fault” will be declared and the ‘Range Fault’ fault bit will be set on the Modbus™ output.

NOTE 2: If the sensor fails the clearing time criteria, a “Clearing Fault” will be declared and the ‘Clearing Fault’ fault bit will be set on the Modbus™ output.

a) Verify that the AutoSpan Level is equal to the Calibration Span Gas Concentration. (Refer to View

Sensor Status in Section 3.4.1.) If the AutoSpan Level is not equal to the Calibration span gas concentration, adjust the AutoSpan Level as instructed in Section 3.3.2 AutoSpan.

b) From Normal Operation, enter Calibration Mode by holding the programming magnet over PGM1 for 3

seconds. Note, the “” prompt will show that the magnetic switch is activated during the 3 second hold period. The display will then scroll “PGM1=Zero PGM2=Span”. Hold the programming magnet over PGM2 for 3 seconds to execute AutoSpan (or allow to timeout in 5 seconds if AutoSpan is not intended). The ITM will then scroll “Apply XX ppm Gas”.

the sensor is in-calibration mode. This bit will remain set until the program returns to normal

c) Apply the span calibration test gas for toxic gas sensors at a flow rate of 200-500cc/min (500cc/min is the

recommended flow rate). As the sensor signal begins to increase the display will switch to flashing “XX“ reading as the ITM shows the sensor’s “as found” response to the span gas presented. If it fails to meet the minimu m in-range signal change criteria within 2 minutes, the display will report “Range Fault” twice and the ITM will return to normal operation, aborting the AutoSpan sequence. The ITM will continue to report a “Range Fault” for 1 minute.

Assuming acceptable sensor signal change, after 1 minute the reading will auto-adjust to the programmed AutoSpan level. The ITM then reports the following messages:

“Remove Gas” d) Remove the span gas source and calibration adapter. The ITM will report a live reading as it clears toward

“0”. When the reading clears below 10% of range, the ITM will display “Span Complete” and will revert to normal operation. If the sensor fails to clear to less than 10% in less than 5 minutes, a “Clearing Fault” will be reported twice and the ITM will return to normal operation, aborting the AutoSpan sequence. The ITM will continue to report a “Clearing Fault” for 1 minute.

e) AutoSpan calibration is complete.

CXT-DM Instruction Ma nu al Rev. 1.6 Page 21 of 52

Model CXT-DM

3.4 Program M ode

Program Mode provides a “View Sensor Status” menu to check operational and configuration parameters. Program Mode provides for adjustment of the detection range, AutoSpan Level, RF Channel, and Modbus ID. Additionally, Program Mode includes the diagnostic function “Bump Test” and “Restore Defaults”.

The Program Mode menu items appear in the order presented below:

View Sensor Status Set Detection Range Set Autospan Level Bump Test Restore Defaults Set RF Channel Set Modbus ID

Navigating Program Mode

From Normal Operation, enter Program Mode by holding the magnet over PGM2 for 3 seconds. Note, the “” prompt will show that the magnetic switch is activated during the 3 second hold period. If the sensor is experiencing a fault condition the “” prompt will not appear until the fault(s) have been displayed. The ITM will enter Program Mode and the display will display the first menu item “View Sensor Status”. To advance to the next menu item, hold the magnet over PGM1 or PGM2 while the current menu item’s text is scrolling. At the conclusion of the text scroll the arrow prompt (“” for PGM2 or “” for PGM1) will appear, and immediately remove the magnet. The ITM will advance to the next menu item. Repeat this process until the desired menu item is displayed. Note, PGM1 moves the menu items from right to left and PGM2 moves the menu items from left to right.

To enter a menu item, hold the magnet over PGM1 or PGM2 while the menu item is scrolling. At the conclusion of the text scroll the “”prompt (“” for PGM2 or “” for PGM1) will appear, continue to hold the magnet over PGM1 or PGM2 for an additional 3-4 seconds to enter the selected menu item. If there is no magnet activity while the menu item text is scrolling (typically 4 repeated text scrolls), the ITM will automatically revert to Normal Operation.

3.4.1 View Sensor Status

View Sensor Status displays all current configuration and operational parameters including: sensor type,

software version number, gas type, detection range, AutoSpan level, days since last AutoSpan, estimated remaining sensor life, raw sensor current, mA output, input voltage and sensor ambient temperature.

From t he View Sensor Status text scroll, hold the magnet over PGM1 or PGM2 until the “” prompt appears and continue to hold the magnet in place for an additional 3-4 seconds (until the display starts to scroll “Status

Is”). The display will scroll the complete list of sensor status parameters sequentially:

Main processor firmware version

The menu item appears as: “Mp App ##.##”

Co-processor firmware version

The menu item appears as: “Cp App ##.##”

Rf firmware version

CXT-DM Instruction Ma nu al Rev. 1.6 Page 22 of 52

Model CXT-DM

The menu item appears as: “Rf App ##.##.##”

Rf Software version

The menu item appears as: “Rf Sw ##.##”

Modbus ID

The menu item appears as: “Modbus ID is ##”

Serial Number

The menu item appears as: “Serial Number ##.##.##”. This is the serial number for the radio embedded in the CXT-DM.

RF Channel

The menu item appears as: “RF Channel ##”

Network ID

The menu item appears as: “Network ID ####”

Range

The menu item appears as: “Range ###”

AutoSpan Level

The menu item appears as: “Auto Span Level ##”

Temperature Compensation Level

The menu item appears as: “Tempcomp Level ##”

Last Cal

The menu item appears as: “Last Cal ## Days”

Sensor Life

The menu item appears as: “Sensor Life ###%”

Temperature

The menu item appears as: “Temperature ##C”

When the status list sequence is complete, the ITM will revert to the “View Sensor Status” text scroll. The user can either: 1) review list again by executing another 3-4 second hold, 2) move to another menu item by executing a momentary hold over PGM1 or PGM2, or 3) return to Normal Operation via automatic timeout of about 15 seconds (the display will scroll “View Sensor Status” 4 times and then return to Normal Operation).

3.4.2 Set Detection Range

The ful l-scale range of a CXT-DM sensor is determined at the time of order. The Plug-in Sensor is fact ory calibrated for this range. The range should not be changed in the field unless directed to do so by Detcon.

CXT-DM Instruction Ma nu al Rev. 1.6 Page 23 of 52

Model CXT-DM

NOTE1: The sensor range should not be changed in the field unless directed to do so by Detcon.

3.4.3 Set Autospan Level

Set Autospan Level is used to set the span gas concentration level that is being used to calibrate the sensor.

This level is adjustable from 1% to approximately 75% or 95% dependent on full-scale range. The current setting can be viewed in View Program Status.

The menu item appears as: “Set AutoSpan Level”

From the Set AutoSpan Level text scroll, hold the magnet over PGM1 or PGM2 until the “” prompt appears and continue to hold the magnet in place for an additional 3-4 seconds (until the display starts to scroll “Set Level”). The display will switch to “XX“(where XX is the current gas level). Swipe the magnet momentarily over PGM2 to increase or PGM1 to decrease the AutoSpan Level until the correct level is displayed. When the correct level is achieved, hold the magnet over PGM2 for 3-4 seconds to accept the new value. The display will scroll “Level Saved”, and revert to “Set AutoSpan Level” text scroll.

Move to another menu item by executing a momentary hold, or return to Normal Operation via automatic timeout of about 15 seconds (the display will scroll “Set AutoSpan Level” 4 times and then return to Normal Operation).

3.4.4 Bump Test

Bump Test is used to check the response of the sensor with the indication of response limited to the display

only. The B ump Te st mode allows the performance of the sensor to be checked without firing the alarms of any attached control systems. The results of the bump test will not affect the reading register on the Modbus™ output.

The menu item appears as: “Bump Test”

From the Bump Test text scroll, hold the magnet over PGM1 or PGM2 until the “” prompt appears and continue to hold the magnet in place for an additional 3-4 seconds (until the display starts to scroll “Bump Test Started”).

Apply span gas to the sensor according to Section 2.6.1 Toxic Gas Sensors. The Sensor will respond to the gas to test the sensor response, but the Modbus current gas reading (Modbus register 0002) will remain unchanged. Remove the gas before the ‘Bump Test’ time expires (2 minutes).

The display will return to normal operation and alternate between the live gas reading, and showing “Bump” until 2 minutes expires, or the execution of a momentary hold over PGM1 or PGM2, when the display will scroll “Bump Test Ended”.

3.4.5 Restore Defaults

Restore Factory Defaults is used to clear current user configuration and calibration data from memory and

revert to factory default values. This may be required if the settings have been configured improperly and a known reference point needs to be re-established to correct the problem.

This menu item appears as: “Restore Defaults”.

CXT-DM Instruction Ma nu al Rev. 1.6 Page 24 of 52

Model CXT-DM

NOTE: Restoring factory defaults should only be used when absolutely necessary. All previously

magnet hold on PGM 2 is required to execute this function.

NOTE: The following must be performed in order before the sensor can be placed in operation.

existing configuration inputs will have to be re-entered if this function is executed. A full 10-second

From the “Restore Defaults” text scroll, hold the programming magnet over PGM2 until the “” prompt appears and continue to hold for 3-4 seconds. The display will scroll “Defaults Restored”, and revert to “Restore Defaults” text scroll.

Move to another menu item by executing a momentary hold, or, return to Normal Operation via automatic timeout of about 15 seconds (the display will sc roll “Restore Defaults” 4 times and then return to Normal Operation).

Following the execution of “Restore Defaults”, the CXT-DM will revert to its factory default settings. The default settings are:

• RF Channel = 4. The RF Channel should be set appropriately by the operator (Section 3.4.6).

• Modbus ID = 01. The Modbus ID must be set appropriately by the operator (Section 3.4.7).

• AutoSpan Level = 50% of range. AutoSpan level must be set appropriately by the operator (Section

3.4.3).

• Range: Defaults to range of intelligent plug-in sensor, must be set to the appropriate level by the operator

(Section 3.4.2).

• AutoZero: AutoZero Settings are lost and user must perform new AutoZero (Section 3.3.1).

• AutoSpan: AutoSpan Settings are lost and user must perform new AutoSpan (Section 3.3.2).

3.4.6 Set RF Channel

Set RF Channel is used to set the RF Channel used for communication. There are 16 possible RF channels.

All of the sensors must be on the same RF Channel for the network to operate properly. The RF Channel is settable from 0 to 15. The current RF Channel can be viewed in View Sensor Status.

The menu item appears as: “Set RF Channel”.

From the “Set RF Channel” text scroll, hold the programming magnet over PGM1 or PGM2 until the “” prompt appears and continue to hold the magnet in place for an additional 3-4 seconds (until the display starts to scroll “Set Channel”). The display will then switch to “XX“ (where XX is the current RF Channel). Swipe the magnet momentarily over PGM2 to increase or PGM1 to decrease the hexadecimal number until the desired ID is displayed. Hold the magnet over PGM2 for 3-4 seconds to accept the new value. The display will scroll “Channel Saved”, and revert to “Set RF Channel” text scroll.

Move to another menu item by executing a momentary hold, or, return to Normal Operation via automatic timeout of about 15 seconds (the display will scroll “Set RF Channel” 5 times and then return to Normal Operation).

3.4.7 Set Modbus ID

Detcon CXT sensor can be polled serially via Modbus™ RTU. Refer to Section 4.0 for details on using the Modbus™ output feature.

Set Modbus ID is used to set the Modbus™ address of the unit. It is adjustable from 01 to 256 in hexadecimal format (01-FF hex). Each sensor must have a unique Modbus address to operate correctly on the network. The current serial ID can be viewed in View Sensor Status.

CXT-DM Instruction Ma nu al Rev. 1.6 Page 25 of 52

Model CXT-DM

The menu item appears as: “Set Serial ID”.

From the “Set Modbus ID” text scroll, hold the programming magnet over PGM1 or PGM2 until the “” prompt appears and continue to hold the magnet in place for an additional 3-4 seconds (until the display starts to scroll “Set ID”). The display will then switch to “XX” (where XX is the current ID address). Swipe the magnet momentarily over PGM2 to increase or PGM1 to decrease the hexadecimal number until the desired ID is displayed. Hold the magnet over PGM2 for 3-4 seconds to accept the new value. The display will scroll “ID Saved”, and revert to “Set Modbus ID” text scroll.

Move to another menu item by executing a momentary hold, or, return to Normal Operation via automatic timeout of about 15 seconds (the display will scroll “Set Serial ID” 5 times and then return to Normal Operation).

3.5 Fault Diagnostic/Failsafe Feature

If th e IT M s hould incur a fault, the Global Fault bit will be set on the Modbus™ output. This can occur if the ITM detects a problem with the sensor, detects that there is no sensor connected, if the ITM has an internal fault, or other fault condition. The Global Fault bit will be set on the Modbus™ output until the problem is resolved. The display will show the Fault when a magnetic programming tool is swiped across either PGM1 or PGM2. The error codes are defined in section 6 Troubleshooting Guide.

CXT-DM Instruction Ma nu al Rev. 1.6 Page 26 of 52

Model CXT-DM

Address Field

Function Code

Data

CRC

4. Modbus™ Communications

Modbus ™ communication with a CXT Sensor is normally accomplished using another wireless transceiver such as the RXT-320 which is connected through a RS-485 interface to a Modbus™ master control unit. The control unit can then access the Modbus™ registers within the CXT Sensor to obtain readings and status of the sensor.

As with normal Modbus™ operation, there can be only one Modbus™ master that polls all the other devices on the network which are considered Modbus™ slaves. Each sensor must have a unique Modbus™ address to work properly on the wireless network. Also each device on the wireless network must be on the same RF channel to communicate with one another. Both the Modbus ID and the RF Channel are set on the CXT Sensor using the display.

The Modbus™ master control unit with RXT-320 transceiver (or equivalent) is responsible for broadcasting requests and receiving slave device responses. The CXT Sensor receives these requests through its own internal transceiver and responds if the Modbus™ address and proper register set matches. The response will be received by the RXT-320 and presented to the master control unit across the RS-485 interface.

4.1 General Modbus™ De scr ip ti on

The Modbus™ communication uses the RTU transmission mode per the Modbus™ specification. The basic frame format for Modbus™ consists of a Modbus™ address, function code, data and CRC.

Figure 17 Modbus™ Frame Format

The Modbus ID Field is the unique Modbus™ address of each device on the network. The Function Code is the function to be performed. The Data contains read or write data and is formatted according to the function being performed. The CRC (Cyclic Redundancy Code) is used to detect errors in the frame. Frames with errors are invalid and ignored.

Modbus™ transactions consist of both a request by the controller and response from the device being addressed so there are two frames transferred for every transaction. Every request is evaluated by the CXT to determine if it is addressed to it, and if it falls within the register address range. If these two conditions are true, the CXT will then check to see if it is a valid Function Code. Function Codes supported by the CXT are:

Function Code 03 (03h) – Read Holding Registers Function Code 06 (06h) – Write Single Register Function Code 16 (10h) – Write Mult iple Reg ist ers

If an invalid function code is performed, the CXT will ignore the request by default and the controller will timeout and continue with the next transaction.

4.1.1 Modbus™ Exceptions

The CXT is capable of returning Modbus™ exceptions when it cannot service a Modbus™ request meant for that CXT. By default this is turned off since it can cause issues with some controllers that do not proc ess Modbus™ exceptions (See Section 4.2.2.4 Register – Control). The following exception codes are supported and returned when Modbus™ exceptions are enabled:

CXT-DM Instruction Ma nu al Rev. 1.6 Page 27 of 52

Model CXT-DM

Exception

Code

Unsupported function code. Only 03, 06 and 16 are supported.

Invalid register address detected. If any request for registers

exception code will be returned.

NOTE: When using Detcon controllers, Modbus exceptions should be turned off.

NOTE: Controllers that generate Modbus™ broadcast requests to the CXT must ensure a

turnaround delay of 150ms is met otherwise the next request can cause the broadcast request to be overwritten and ignored.

NOTE: A write to a Read Only register is allowed and returns a response, but it does not change the value of the register. In some devices this would return an exception code.

Table 1 Exception Codes

Name Meaning

01 Illegal Function

02 Illegal Data Address

outside of the valid register address for the CXT occurs, this

There are other exception codes defined in Modbus™ but these are the only ones used by the CXT.

4.1.2 Modbus™ Broadcast Requests

The Modbus™ broadcast request was introduced in the CXT to support commands to be executed across all CXT transceivers simultaneously. More specifically this is used to place all CXTs in a low power state for a specified time to conserve battery life. Only the transceivers (radio) are placed into a low power state, the CXT sensor will continue to operate normally. If none of the CXTs are battery powered then there is no need to issue a command to place the transceivers in low power mode.

According to the Modbus™ specification a broadcast request is defined as a request with the Address Field set to 0 and is used for writing only. There is no response returned as with normal Modbus™ transactions since all devices on the system are accessed at the same time. Both Function Codes 06 and 16 (writes) are supported with a broadcast request on the CXT.

Since there is no response on the broadcast request, there is a requirement to wait for a period of time before sending out the next request. This allows all slave devices to process the command before the next request is received. This is defined as the “turnaround delay”. This turnaround delay should be approximately 150 milliseconds for broadcast requests sent to the CXT. Controllers in general can meet this timing because it takes longer than this to generate the next request so it may be unnecessary to make any adjustments to meet this timing.

Broadcast requests are not confined to commands to put the network in low power mode, but can be used where any normal write command is used.

4.2 Modbus™ Register Map & Description

When the CXT is assigned a Modbus™ address, the following registers become available to the controller for access. All CXT sensors implement this register set. Some registers are Read Only (R) and others are Read/Write (R/W) as shown by the R/W column. This equates to specific function codes where Read is function code 03 and Write is function code 06 or 16.

The following table is the register map for the CXT sensor and gives a brief description each register or register set. This information is only meant as a reference. The registers are divided into two sections, one for

CXT-DM Instruction Ma nu al Rev. 1.6 Page 28 of 52

Model CXT-DM

Offset

Name

R/W

Comment

0000

CXT-DM-100 Device Type

R

= 36

0001

Range

R/W

Detectable Range

0002

Reading

R

Current Gas Reading

0003

Calibration Level

R/W

Auto Span Level

0004

Life

R

Sensor Life

0005

Sensor Faults

R

Fault bits

0006

Sensor Model

R

DM (set to 1)

0007

Days since Calibration

R

0008

Reserved

R

0009

Reserved

R 0010

Sensor Temperature

R 0011

DECIMAL

R/W

0012

Temperature Compensation

R/W

0013

Reserved

R

0014

COUNTS

R/W

0015

CONTROL

R/W

0016

String

R

Set during production/test

0017

String

R

Set during production/test

0018

String

R

Set during production/test

0019

String

R

Set during production/test

0020

String

R

Set during production/test

0021

String

R

Set during production/test

0022

Reserved

R/W

NOT USED

0023

Sensor Controller Version

R

Year.Week

0024

Reserved

R

0025

Reserved

R

0026

Reserved

R

0027

Wireless Controller Version

R

Major.Minor

0028

Reserved

R 0029

Radio Firmware Version

R

00.Major

0030

Radio Firmware Version

R

Minor.Build

0031

Radio Software Version

R

Major.Minor

0032

Wireless ID High

R

00.XX

0033

Wireless ID Low

R

XX.XX

0034

RF Channel

R

Wireless RF Channel (Set in Display)

0035

Network ID

R

Defaults to RF Channel (Set in Display)

0036

Modbus Address

R

CXT Modbus Address (Set in Display)

RXT-320 Compatible Registers for Wireless Transceiver

8192

RXT-320 Device Type

R

22 (for compatibility)

8193

Reserved

--

8194

Reserved

--

8195

Reserved

-- 8196

Reserved

-- 8197

Reserved

-- 8198

Reserved

--

the CXT sensor and the other for the CXT transceiver. For a more detailed description of the Register Map please contact Detcon.

Table 2 CXT-DM Register Map

CXT-DM Instruction Ma nu al Rev. 1.6 Page 29 of 52

Model CXT-DM

Offset

Name

R/W

Comment

8199

Battery Life in Percent

R

Smart Battery Life remaining in percent

8200

Battery Life in Minute

R

Smart Battery Life remaining in minutes

8201

Wireless Controller Version

R

same as register 0027

8202

RF Update Rate

W

Number of seconds to power down transceiver

8203

Control

R/W

Wireless Control

8204

Status

R

Wireless Status

8205

Input Voltage

R

Smart Battery voltage or Input Voltage to A/D

8206

Battery Error Count

R/W

Smart Battery read error count if detected

8207

Reserved

--

8208

Timestamp[0]

R

Time since power applied -- Seconds High

8209

Timestamp[1]

R

Time since power applied -- Seconds Low

8210

Timestamp[2]

R

Time since power applied -- Milliseconds

4.2.1 CXT Sensor Registers

4.2.1.1 Sensor Faults – Register 0005

The sensor fault status register consists of High and Low Status Bits. These bits are set/reset as faults occur or are cleared. Each bit has a particular meaning:

Register # High Byte Low Byte 0005 Status Bits Status Bits

Bits read as 0 are FALSE; bits read as 1 are TRUE

Status Bits High Byte: Bit 15 – Reserved Bit 14 – Calibration Mode Bit 13 – Reserved Bit 12 – Zero Fault Bit 11 – Range Fault Bit 10 – Reserved Bit 9 – Clearing Fault Bit 8 – Reserved

Status Bits Low Byte: Bit 7 – Sensor Fault Bit 6 – Processor Fault Bit 5 – Memory Fault Bit 4 – Reserved Bit 3 – Reserved Bit 2 – Temperature Fault Bit 1 – Auto Span Fault Bit 0 – Global Fault

CXT-DM Instruction Ma nu al Rev. 1.6 Page 30 of 52

Model CXT-DM

4.2.2 CXT Transceiver Registers

4.2.2.1 Battery Info – Multiple Registers

If a Detcon smart battery pack is connected to the CXT, there are five registers associated with information about that battery. The CXT utilizes the I

2

C interface to read battery status and only one Detcon battery pack

can be read per CXT.

The controller can determine if a battery is present by reading the Status Register (register 8204). There ar e two bits in this sixteen bit register pertaining to the battery, Battery Detect – bit 4 (lowest bit is 0) and Battery Fault – bit 5. Both bits default to a value of 0. Battery Detect will be set once the first read of the battery over

2

the I

C interface was successful. Battery Fault will be set if a battery was detected but the last read failed. Battery Fault is re-evaluated upon every read of the battery which is set to approximately every 5 seconds. Register 8206 (I

2

C Batt Read Fails) will increment by 4 each time there is a failure since there are 4 attempts

before declaring failure. This register can be cleared by writing a 0 to it at any point.

Once the battery has been detected the controller can read the battery life (registers 8199 and 8200). The battery adjusts these values based upon the average current usage. If this usage varies widely over time it will take some time to re-adjust the battery life readings. For instance an Alarm Station with no alarms will consume a very small amount of battery but when Alarms are active this will jump to a much higher level of usage. So in this case battery life may go from several weeks down to several hours.

The batt ery life is presented in two forms, life remaining in percentage (register 8199) and life remaining in minutes (register 8200). The battery Life remaining is percentage is a value between 0 and 100 and battery life in minutes is an unsigned value between 0 and 65535. Both readings are generally necessary to provide appropriate feedback to the user. Life in minutes is the best for determining when to change the battery. For example if the user wanted to be notified a day before the battery needed to be changed, the user could set a threshold in the controller to be notified of low battery after 1440 minutes (1 day).

Since 65535 is the maximum value for life remaining in minutes, this represents a maximum of 45.5 days. The battery life for an application can be much greater than this value and will remain at a reading of 65535 until it drops below this. Life in percentage was added for this reason. Percentage will track starting at 100 percent and drop down as battery life decreases. The controller can therefore use both registers, one to represent usage in percentage to present to the user and then use the life in minutes to set a threshold on when a low battery condition exists for changing the battery.

4.2.2.2 Wireless Controller Version

This is set to a value based upon the version of firmware programmed into the RXT-320 microcontroller. It is stored as two byte value representing the major and minor revision numbers. So a 0113h (275 decimal) represents a major version of 01 and minor version of 13. As software is updated this will be incremented appropriately.

4.2.2.3 Register – Update Rate

The Update Rate represents the amount of time in seconds the CXT transceiver will be in a low power state. Its main purpose is to provide a mechanism to place all wireless transceivers in a system into a low power mode to conserve battery power. If there are no batteries used within the network of wireless transceivers this register would not be utilized.

Upon power up, this register is set to 0 and the CXT transceiver is not in low power mode. To place a network to low power mode the controller will generate a broadcast request (Modbus™ address = 0) and do a single

CXT-DM Instruction Ma nu al Rev. 1.6 Page 31 of 52

Model CXT-DM

write (function code 06) to register 8202 with the number of seconds the network should go into low power mode. During low power mode, there can be no access to any device on the network so changes in sensor readings will not be updated. Once a non-zero value is written to this register on all transceivers, they will begin counting down until the Update Rate register reaches zero, at which time all transceivers should be active again and ready for network communication. The controller will monitor the update rate time remaining by accessing Update Rate register on the RXT-320 (or equivalent) that it is attached to it. The Modbus™ interface remains active, only the wireless network is placed in a low power state. The value of this register can be between 0 and 65535 which allows a maximum low power time of 18.2 hours. Removal of power will reset Update Rate to 0 and the transceiver will be active again.

4.2.2.4 Register – Control

The CXT transceiver control register is generally unused and should not be written to normally. Using the control register, the CXT can be reset and Modbus™ exceptions can be enabled. Each bit in the control register can control a particular function and should be read first then modify the bits needed and written back. The default state of the register is 0. All reserved bits should always be set to a 0 when writing. The listing below shows the bit assignments.

Bit 15: Reserved (set to 0) Bit 14: Reserved (set to 0) Bit 13 – 12: Reserved (set to 0) Bit 11: Modbus Exceptions Enabled Bit 10 – 08: Reserved (set to 0) Bit 07: Reset the microcontroller and wireless radio Bit 06: Reset the microcontroller Bit 05 – 00: Reserved (set to 0)

4.2.2.5 Register – Status

This register contains status of the CXT transceiver and some of the bits have already been covered in the battery description. These default to 0 upon reset. The bit assignment and description are given below.

Bit 15 – 08: Reserved (set to 0) Bit 07: Reserved (set to 0) Bit 06: Reserved (set to 1) Bit 05: I2C Fault on last read of Battery Status Bit 04: Battery Detected Bit 03: Reserved (set to 0) Bit 02: Reserved (set to 1) Bit 01: Reserved (set to 0) Bit 00: Reserved (set to 0)

4.2.2.6 Register – Timestamp

Three registers are utilized to maintain a timestamp that increments on the microcontroller after power up. These are all set to 0 upon power up or a microcontroller reset. The first two registers 8208 and 8209 are internally combined into a single 32 bit register and incremented each second. The last register 8210 maintains the millisecond count and will count from 0 to 999 and start over again.

CXT-DM Instruction Ma nu al Rev. 1.6 Page 32 of 52

Model CXT-DM

The safety approvals require removing entire sensor assembly to a non-hazardous area before installing or changing out the batteries or battery pack.

5. Service and Maintenance

Calibration Frequency

In most applications, monthly to quarterly span calibration intervals will assure reliable detection. However, industrial environments differ. Upon initial installation and commissioning, close frequency tests should be performed, weekly to monthly. Test results should be recorded and reviewed to determine a suitable calibration interval.

Visual Inspection

The Sensor should be inspected annually:

• Inspect the sensor for signs of corrosion, pitting, and water damage.

• Remove the Splash Guard and inspected it for blockage, broken, cracked, or missing pieces.

• For H2S Sensor assemblies, inspect CXT-DM Series Splashguard Adapter Assembly with integral

filter (P/N 602-003552-100) for blockage of filter material.

• Inspect inside of the Junction Box for signs of water accumulation, signs of corrosion.

• Check wiring to ensure there are no loose or pinched wires and all connections are clean and tight.

Condensation Prevention Packet

A moisture condensation packet should be installed in every explosion proof Junction Box. The moisture condensation prevention packet will prevent the internal volume of the J-Box from condensing and accumulating moisture due to day-night humidity changes. This packet provides a critical function and should be replaced annually. Detcon’s PN is 960-202200-000.

5.1 Replacement of the batteries/battery pact

5.1.1 Units with 12V Smart Battery Pack

The CX T-DM Sensor incorporates a ‘Low battery’ fault message which will appear as an alternating display between the current gas reading and ‘VOLT’ on the sensor display. This fault will appear when the battery voltage drops below 7.5 volts. When the voltages drops below 7.2 volts the display will change to a steady ‘VOLT’ display, the sensor will then enter into ‘Fault’ mode, and the sensor will no longer provide a valid gas reading.

NOTE

1. Remove the cover from the J-box.

2. Unscrew battery bracket lid, and swing the lid away from the battery pack.

3. Remove the battery pack from the J-box, and replace with new battery pack.

4. Swing the lid back over the battery pack, and re-tighten screws in battery bracket lid.

5. Replace the cover on the J-box.

5.1.2 Units with Tri ‘C’ sized Lithium Battery Holder

NOTE

1. Remove the cover from the J-box

CXT-DM Instruction Ma nu al Rev. 1.6 Page 33 of 52

Model CXT-DM

NOTE: It is not necessary to remove power while changing the plug-in toxic gas sensor in order to maintain area classification, since it is intrinsically safe.

Release Screws to

(+)

(-)

Positive connections to

batteries have coiled spring.

Use only 3.6V

2. Press Tri-C Battery Holder down slightly to disengage latch and rotate counter-clockwise according to

instructions on lid to remove from Enclosure Base. Lift Battery Holder from Enclosure Base.

3. Unscrew the cover screws on the battery holder. The screws are captive screws, removal of the screws

is not necessary.

4. The orientation of batteri es is marked on the inside of t he cover and the holder. Remove the batteries

from the battery holder.

5. Replace the batteries with the same type (Detcon PN 360-026500-000). It is permissible to use only

Tadiran Model TL-5920 batteries. Do NOT use regular ꞌCꞌ size batteries, as this may cause damage to the sensor assembly.

6. All three batteries must be replaced at the same time

7. Pay attention to the orientation of the batteries when installing batteries in the Battery Holder. The

negative (minus) leads of the battery should connect with the negative (minus) leads of the battery holder. The positive (plus) leads of the batteries should connect with the positive (plus) leads of the battery holder.

allow access to remove/replace batteries.

batteries have raised bump.

Negative connections to

Lithium Batteries

Figure 18 Battery Orientation Diagram

8. Reattach the battery cover using screw s.

9. Re-install Tri-C Battery Holder in Enclosure Base, pressing down and rotating clockwise to secure.

The Battery Holder will ‘Snap’ into position when correctly oriented.

10. Replace the cover on the J-box.

5.2 Replacement of Plug-in Sensor

CXT-DM Instruction Ma nu al Rev. 1.6 Page 34 of 52

Model CXT-DM

NOTE: Only replace the plug-in sensor with an authorized CXT-DM family of gas sensors.

ITM

(Bottom View)

Display Window

Plug in Sensor

(Bottom view)

Locking

Setscrew

Locking

Setscrew

NOTE: It is necessary to remove power to the Junction box while changing the ITM in order to maintain area classification.

Figure 19 Sensor Cell and ITM Mating

1. Use a 1/16” Allen wrench to release the locking setscrew that locks the ITM and Splashguard Adapter

Assembly together (One turn will suffice - Do not remove setscrew completely).

2. Remove splashguard. Unthread and remove the Splashguard Adapter Assembly from the ITM.

3. Gently pull the plug-in sensor out of the ITM. Verify the gas type and range of the new sensor cell is

correct. Orient the new plug-in sensor so that it matches with the female connector pins. When properly aligned, press the sensor in firmly to make the proper connection.

4. Thread t he Splashguard Adapter Assembly onto the ITM to a snug fit and tighten the locking setscrew

using the 1/16” Allen wrench. Reinstall the splashguard.

5. Check and perform zero calibration and span calibration as per Section 3.3 Calibration.

5.3 Replacement of ITM – Aluminum J-Box

1. Remove the power source to the sensor assembly, and remove the battery pack from the J-box.

Disconnect all sensor wire connections at the Junction Box Terminal Board, taking note of the wire connections, and disconnect the RF cable connector.

2. Use a wrench and the wrench flats provided at the top section of the ITM and unthread the ITM until it

can be removed.

3. Use a 1/8” Allen wrench to release the locking cap head screw that locks the ITM and Splashguard

Adapter Assembly together (One turn will suffice - Do not remove setscrew completely).

4. Unthread and remove the Splashguard Adapter Assembly and Splash Guard from the ITM. These will

be re-used with the new ITM.

5. Gently remove the plug-in toxic gas sensor from the old ITM and install it in the new ITM. Orient the

plug-in sensor pins so that they matches the female connector pins on the new ITM and press the sensor in firmly to make proper connection.

6. Thread the Splashguard Adapter Assembly onto the new ITM until snug, tighten the locking cap head

screw and reinstall Splash Guard.

CXT-DM Instruction Ma nu al Rev. 1.6 Page 35 of 52

Model CXT-DM

NOTE: It is necessary to remove power to the Junction box while changing the ITM in order to maintain area classification.

7. Feed the sensor assembly wires and RF cable through the ¾” female NPT port and thread the

assembly into the J-box until tight and the ITM faces toward the front access point. Use the locking nut to secure the ITM in this position. Re-connect the sensor assembly wires to the terminal board inside the Junction Box. Re-connect the RF cable to the antenna cable.

8. Re-install the battery pack.

9. Check and/or perform Zero Calibration and Span Calibration per sections 3.3 Calibration.

5.4 Replacement of ITM – Stainless Steel Mini Condulet

1. Remove the cover of the battery holder, and remove the batteries. Remove the battery holder from the

j-box by removing the two 6-32 screws at the bottom of the housing.

2. Disconnect the sensor wire connections from the shorting blocks, taking note of the wire connections.

Disconnect the RF cable connector. (The wire splice shorting blocks can be difficult to remove wires from. By using a pair of needle nose pliers and twisting the wires while pulling them out of the shorting blocks can make the task easier.)

3. Use a wrench and the wrench flats provided at the top section of the ITM and unthread the ITM until it

can be removed.

4. Use a 1/8” Allen wrench to release the locking cap head screw that locks the ITM and Splashguard

Adapter Assembly together (One turn will suffice - Do not remove setscrew completely).

5. Unthread and remove the Splashguard Adapter Assembly and Splash Guard from the ITM. These will

be re-used with the new ITM.

6. Gently remove the plug-in toxic gas sensor from the old ITM and install it in the new ITM. Orient the

plug-in sensor pins so that they match the female connector pins on the new ITM and press the sensor in firmly to make proper connection.

7. Thread the Splashguard Adapter Assembly onto the new ITM until snug, tighten the locking cap head

screw and reinstall Splash Guard.

8. Feed the sensor assembly wires and RF cable through the ¾” female NPT port and thread the

assembly into the J-box until tight and the ITM faces toward the front access point. Use the locking nut to secure the ITM in this position.

9. Re-connect the sensor assembly wires to the shorting blocks by pushing the wire straight into the

block board inside the Junction Box. (Red to red, and black to black. Re-connect the RF cable to the antenna cable.

10. Re-install the battery holder in the J-box, and re-install the batteries into the housing. Replace the

battery holder cover.

11. Check and/or perform Zero Calibration and Span Calibration per sections 3.3 Calibration.

CXT-DM Instruction Ma nu al Rev. 1.6 Page 36 of 52

Model CXT-DM

6. Troubleshooting Guide

If the ITM detects any functional errors the ITM will display the fault. If the sensor is experiencing a fault condition a momentary swipe of the magnet will cause the ITM to scroll the fault condition(s) across the display before the “” or “” prompt will appear.

The Display Error Codes are: Auto Span Fault Temperature Fault Memory Fault Processor Fault Clearing Fault Range Fault Sensor Fault Zero Fault Sensor Fault 2

Some faults are self-explanatory, and if these faults occur and cannot be cleared the ITM should be replaced first to see if the fault will clear. Other faults may need further investigation. Some of the sensor problems, associated error codes, and resolution s are lis ted belo w.

Under-Range problems

Probable Cause: Sensor Baseline drifted lower, Interference gases,

• Perform Zero Calibration. Use Zero Air or N

source. (Section3.3.1 AutoZero)

2

• Allow more time for zero stabilization if this is a biased sensor type.

• Execute successful Span Calibration. (Section 3.3.2 AutoSpan)

• Replace plug-in toxic sensor if error continues.

Stability problems

Probable Causes: Failed Sensor, empty or close to empty Cal Gas Cylinder, problems with cal gas and delivery

• Check validity of span gas using pull tube or other means (check MFG date on cal gas cylinder).

• Use proper cal gas regulators and tubing for highly corrosive gases

• If using Splashguard with Integral Cal Port, must use Calibration Wind Guard or air movement can

compromise span gas delivery.

• Check for obstructions affecting cal gas hitting sensor face (including being wet, blocked, or

corroded). H2S sensors assemblies use CXT-DM Series Splashguard Adapter Assembly with integral filter. Clean or replace if necessary.

• Replace the plug-in toxic sensor.

Clearing problem

Probable Causes: Failed Sensor, Cal Gas not removed at appropriate time, problems with cal gas and delivery, Background of Target Gas.

• The sensor must recover to < 5% of range in < 5 min after Span calibration is complete

• Use bottled air (zero air or N

) if there is a known continuous background level.

2

• Check validity of span gas using pull tube or other means (check MFG date on cal gas cylinder).

• Use proper cal gas regulators and tubing for highly corrosive gases

• Check for obstructions affecting cal gas hitting sensor face (including being wet, blocked, or

corroded). H2S sensors assemblies use CXT_DM Series Splashguard Adapter Assembly with integral filter. Clean or replace if necessary.

CXT-DM Instruction Ma nu al Rev. 1.6 Page 37 of 52

Model CXT-DM

Contact the Detcon Service Department for further troubleshooting assistance at 281-367-4100.

• Replace the plug-in toxic sensor.

Poor Calibration Repeatability

Probable Causes: Failed Sensor, use of wrong Cal Gas or problems w/ cal gas and delivery, Interference Gases

• Check validity of span gas with regulator and sample tubing in place using pull tube or other means

(check MFG date on cal gas cylinder).

• Use proper cal gas regulators and tubing for highly corrosive gases (HF, HCI, Cl2, NH3, HBR, F2,

etc.)

• Check for obstructions affecting cal gas hitting sensor face (including being wet, blocked, or

corroded). H2S sensors assemblies use CXT-DM Series Splashguard Adapter Assembly with integral filter. Clean or replace if necessary.

• Replace the plug-in toxic sensor.

Unstable Output/ sudden spiking

Possible Causes: Unstable power supply, inadequate grounding, or inadequate RFI protection.

• Verify Power source is stable.

• Verify field wiring is properly shielded and grounded.

• Contact Detcon to optimize shielding and grounding.

• Add Detcon’s RFI Protection Circuit accessory if problem is proven RFI induced.

Nuisance Alarms

• Check condulet for accumulated water and abnormal corrosion on terminal board.

• If nuisance alarms are happening at night, suspect condensation in condulet.

• Add or replace Detcon’s Condensation Prevention Packet P/N 960-202200-000.

• Investigate the presence of other target gases that are causing cross-interference signals.

• Determine if cause is RFI induced.

Transmitter not respondi ng

• Verify condulet has no accumulated water or abnormal corrosion.

• Verify required batteries are installed and have enough charge to power the sensor.

• Swap with a known-good ITM to determine if ITM is faulty.

Low Battery / Low Voltage Fault

Possible Cause: Lithium Ion batteries are depleted.

• Change out all three of the Lithium Ion non-rechargeable ‘C’ size batteries with new batteries.

NOTE

CXT-DM Instruction Ma nu al Rev. 1.6 Page 38 of 52

Model CXT-DM

7. Customer Support and Service Policy

Detcon Headquarters Shipping Address: 4055 Technology Forest Blvd, Suite 100, The Woodlands Texas 77381 Mailing Address: P.O. Box 8067, The Woodlands Texas 77387-8067 Phone: 888.367.4286, or 281.367.4100 Fax: 281.292.2860

• www.detcon.com

• service@detcon.com

• sales@detcon.com

All Technical Service and Repair activities should be handled by the Detcon Service Department via phone, fax or email at contact information given above. RMA numbers should be obtained from the Detcon Service Department prior to equipment being returned. For on-line technical service, customers should have ready the model number, part number, and serial number of product(s) in question.

All Sales activities (including spare parts purchase) should be handled by the Detcon Sales Department via phone, fax or email at contact information given above.

Warranty Notice

Detcon Inc. warrants the Model CXT-DM gas sensor to be free from defects in workmanship of material under normal use and service for one year from the date of shipment on the transmitter electronics. See Warranty details in section 8 CXT-DM Sensor Warranty .

Detcon Inc. will repair or replace without charge any such equipment found to be defective during the warranty period. Full determination of the nature of, and responsibility for, defective or damaged equipment will be made by Detcon Inc. personnel.

Defective or damaged equipment must be shipped to the Detcon Inc. factory or representative from which the original shipment was made. In all cases, this warranty is limited to the cost of the equipment supplied by Detcon Inc. The customer will assume all liability for the misuse of this equipment by its employees or other contracted personnel.

All warranties are contingent upon the proper use in the application for which the product was intended and does not cover products which have been modified or repaired without Detcon Inc. approval, or which have been subjected to neglect, accident, improper installation or application, or on which the original identification marks have been removed or altered.

Except for the express warranty stated above, Detcon Inc. disclaims all warranties with regard to the products sold. Including all implied warranties of merchantability and fitness and the express warranties stated herein are in lieu of all obligations or liabilities on the part of Detcon Inc. for damages including, but not limited to, consequential damages arising out of, or in connection with, the performance of the product.

CXT-DM Instruction Ma nu al Rev. 1.6 Page 39 of 52

Model CXT-DM

8. CXT-DM Sensor Warranty

Plug-in Sensor Warranty

Detcon Inc. warrants, under normal intended use, each new plug-in sensor per the period specified in the Warranty column of Table 3 Sensor Specific Data (See section 9.2 Sensor Specific Data) and under the conditions described as follows: The warranty period begins on the date of shipment to the original purchaser. The sensor element is warranted to be free of defects in material and workmanship. Should any sensor fail to perform in accordance with published specifications within the warranty period, return the defective part to Detcon, Inc., 4055 Technology Forest Dr., The Woodlands, Texas 77381, for necessary repairs or replacement.

Terms & Conditions

• The original serial number must be legible on each sensor element base.

• Shipping point is FOB the Detcon factory.

• Net payment is due within 30 days of invoice.

• Detcon, Inc. reserves the right to refund the original purchase price in lieu of sensor replacement.

ITM Electronics Warranty

Detcon Inc. warrants, under intended normal use, each new Compact Wireless Sensor ITM to be free from defects in material and workmanship for a period of one year from the date of shipment to the original purchaser. All warranties and service policies are FOB the Detcon facility located in The Woodlands, Texas.

Terms & Conditions

• The original serial number must be legible on each ITM.

• Shipping point is FOB the Detcon factory.

• Net payment is due within 30 days of invoice.

• Detcon, Inc. reserves the right to refund the original purchase price in lieu of ITM replacement.

CXT-DM Instruction Ma nu al Rev. 1.6 Page 40 of 52

Model CXT-DM

9. Appendix

9.1 Specifications

9.1.1 System Specifications

Sensor Type: Continuous diffusion/adsorption type

3-Electrode Electrochemical Sensor (2-Electrode for O Plug-in Replaceable Type

Sensor Life: 2 years typical

Measuring Ranges: 0-1ppm up to 0-10,000ppm (Toxic Gases) 0-1% up to 0-25% volume (O

)

2

Accuracy/ Repeatability: ±2% of full-range (Toxic Gases) ±1% of full-range (O

)

2

Response Time: T90 < 30 seconds typical (See Sensor Table)

Warranty: Electronics – 1 year Sensor – See Table 3 Sensor Specific Data

9.1.2 Environmental Specifications

Operating Temperature: -40°C to +50°C typical (See Table 3 Sensor Specific Data ) Storage Temperature: -35°C to +55°C typical Operating Humidity: 10-95% RH Continuous Duty (See Table 3 Sensor Specific Data)

0-100% RH Short-Term Duration Only

Operating Pressure: Ambient ± 10%

Air Velocity: 0-5 meters/second

9.1.3 Electrical Specifications

Input Voltage: 7-30 VDC

Power Consumption: 20mW (Low Power Mode) 100mW (Typical) 500mW (Max)

RFI/EMI Protection: Complies with EN61326

Cable Requirements: Power/Analog: 2-wire shielded cable

Maximum distance is 13,300 feet with 14 AWG

)

2

CXT-DM Instruction Ma nu al Rev. 1.6 Page 41 of 52

Model CXT-DM

Response Time

(seconds)

Temperature

Range °C

Humidity

Range%

Warranty

3

<5%signal

loss/year

3

<5%signal

loss/year

3

<5%signal

loss/year

3

<2%signal

loss/month

3

<5%signal

loss/month

3

<2%signal

loss/month

3

<5%signal

loss/year

Carbon Monoxide

3

<5%signal

loss/year

3

<2%signal

loss/month

ClO2 (>10ppm)

Chlorine Dioxide

3

<2%signal

loss/month

ClO2 (<=10ppm)

Chlorine Dioxide

3

<1%signal

loss/month

3

<5%signal

loss/month

3

<5%signal

loss/year

Ethyl Mercaptan

371

<2%signal

loss/month

3

<5%signal

loss/year

3

<5%signal

loss/year

3

<5%signal

loss/year

3

<5%signal

loss/year

3

<1%signal

loss/month

9.1.4 Mechanical Specifications

Length: ITM - 5.165 inches (131 mm), 8.5 inches (215mm) with Splash Guard

Width: 2.2 inches (55 mm)

Weight: 2.5 lbs (1.2 Kg)

Mechanical Connection: ¾” Male NPT threaded connection with locking nut

Electrical Connection: four 18 gauge wire leads - 5.5” long with RF Cable terminated at SMA

9.2 Sensor Specific Data

Table 3 Sensor Specific Data

Gas GasName Part Number1

O2

C2H3O

C2H2

NH3

AsH3

Br2

C4H6

CO

Cl2

B2H6

Oxygen

Acetaldehyde

Acetylene

Ammonia

Arsine

Bromine

Butadiene

Chlorine

Diborane

71-343400-025

71-12EA00-100 T90<140

71-12EG00-100 T90<140

71-171700-100

71-191900-001

71-747500-005

71-12EB00-100 T90<140

71-444400-100

71-747400-010

71-777700-001

71-282800-050 T90<120

71-192100-005

T95<30

T90<90

T90<60

T90=30

T90<60

SpanDrift

-20 to+50 15 to 90 2 years

-20 to+40 20 to 95 1.5 years

-20 to+50 15 to 90 2 years

-40 to+50 15 to 90 3 years

-20 to+50 15 to 90 2 years

-20 to+40 10 to 95 2 years

-20 to+40 20 to 95 1.5 years

C2H5OH

C2H5SH

C2H4

C2H4O

F2

CH2O

GeH4

1

The last three digits of the Part Number are the range of the sensor cell. I.E. “-100” is a 100ppm range.

CXT-DM Instruction Ma nu al Rev. 1.6 Page 42 of 52

Ethanol

Ethylene

Ethylene Oxide

Fluorine

Formaldehyde

Germane

71-12EO00-100 T90<140

-24EZ00-100

71-12ED00-100 T90<140

71-12EJ00-100 T90<140

71-272700-001

71-12EP00-100 T90<140

71-232500-002

T90<45

T90<80

T90<60

-20 to+50 15 to 90 2 years

-40 to+50 15 to 90 2 years

-20 to+50 15 to 90 2 years

-10 to+40 10 to 95 1.5 years

-20 to+50 15 to 90 2 years

-20 to+40 20 to 95 1.5 years

Model CXT-DM

Response Time

(seconds)

Temperature

Range °C

Humidity

Range%

Warranty

3

<5%signal

loss/month

3

<2%signal

loss/month

3

<2%signal

loss/month

Hydrogen Bromide

371

<3%signal

loss/month

1.5 years

Hydrogen Chloride

3

<2%signal

loss/month

1.5 years

Hydrogen Cyanide

3

<5%signal

loss/month

Hydrogen Fluoride

3

<10%signal

loss/month

Hydrogen Sulfide

3

<2%signal

loss/month

3

<5%signal

loss/year

Methyl Mercaptan

3

<2%signal

loss/month

3

<2%signal

loss/month

Nitrogen Dioxide

3

<2%signal

loss/month

3

<1%signal

loss/month

3

<1%signal

loss/month

1.5 years

3

<1%signal

loss/month

1.5 years

3

<1%signal

loss/month

1.5 years

3

<2%signal

loss/month

Gas GasName Part Number1

N2H4

H2 (ppm)

H2 (LEL)*

HBr

HCl

HCN

HF

H2S

CH3OH

CH3SH

NO

NO2

Hydrazine

Hydrogen

Methanol

Nitric Oxide

71-262600-001 T90<120

71-848400-100

71-050500-04P

-090800-030

71-090900-030

71-131300-030

71-333300-010

71-242400-100

71-12EE00-100 T90<140

71-24EK00-100

71-949400-100

71-646400-010

T90=30

T90<60

T90<70

T90<40

T90<90

T80<30

T90<45

T90=10

T90<40

SpanDrift

-10 to+40 10 to 95 1 year

-20 to+50 15 to 90 2 years

-40 to+40 5 to 95 2 years

-20 to+40 10 to 95

-40 to+40 5 to 95 2 years

-20 to+35 10 to 80 1.5 years

-40 to+50 15 to 90 2 years

-20 to+50 15 to 90 2 years

-40 to+50 15 to 90 2 years

-20 to+50 15 to 90 3 years

-20 to+50 15 to 90 2 years

O3

COCl2

PH3

SiH4

SO2

1

The last three digits of the Part Number are the range of the sensor cell. I.E. “-100” is a 100ppm range.

Ozone

Phosgene

Phosphine

Silane

Sulfur Dioxide

71-999900-001 T90<120

71-414100-001 T90<120

71-192000-005

71-232300-050

71-555500-020

T90<30

T90<60

T90=20

-10 to+40 10 to 95 2 years

-20 to+40 10 to 95

-20 to+40 20 to 95

-20 to+50 15 to 90 2 years

CXT-DM Instruction Ma nu al Rev. 1.6 Page 43 of 52

Model CXT-DM

Acetaldehyde

Dimethyl Sulfide

Methane

Acetylene

Disilane

Methanol

Acrylonitrile

Epichlorohydrin

ketone

Alcohols

Ethanol

Methyl Mercaptan

Amines

Ethyl Mercaptan

Nitric Oxide

Ammonia

Ethylene

Nitrogen

Arsenic Trifluoride

Ethylene Oxide

Nitrogen Dioxide

Arsenic Pentafluoride

Fluorine

Ozone

Arsine

Formaldehyde

Phosgene

Boron Trifluoride

Germane

Phosphine

Bromine

Hydrazine

Butadiene

Hydrocarbons

Silane

turated)

Silicon

Hydrogen

Silicon Tetra Fluoride

Carbon Disulfide

Hydrogen Bromide

Sulfur Dioxide

Carbon Oxide Sulfide

Hydrogen Chloride

Tetrahydrothiophene

Carbon Monoxide

Hydrogen Cyanide

Thiophane

Carbonyl Sulfide

Hydrogen Fluoride

Toluene

3

Chlorine

Hydrogen Selenide

Tungsten Hexafluoride

Chlorine Dioxide

Hydrogen Sulfide

Vinyl Acetate

Chlorine Trifluoride

Dimethyl Sulfide

Vinyl Chloride

Diborane

9.3 Interference Table

Refer to Table 4 Interfering Gases to match the interfering gas symbol with the gas name. Then refer to Table 5 Cross Interference Table which extends for 5 pages, with each sensor specific gas repeated in each section of the table, for a column listing of 40 gases. The list is followed by a row of 14 possible interfering gases per page. Review each page for the applicable sensor gas and then scan across the row for possible interference gases.

Table 4 Interfering Gases

C2H3O C2H2 C3H3N Alcohols Amines NH3 AsF3 AsF5 AsH3 BF3 Br2 C4H6

Buten-1 Buten-1 Hydrocarbons (unsa

Carbon Dioxide CO2

CS2 COS CO CS Cl2 ClO2 ClF3 B2H6

C2H6S Si2H6 C3H5OCl Methyl-ethylC2H5OH C2H5SH C2H4 C2H4O F2 CH2O GeH4 N2H4 Phosphorous Trifluoride PF3 C-H's C-H's (μ) H2 HBr HCl HCN HF HSe H2S C2H6S

CH4 CH3OH C4H8O CH3SH NO N2 NO2 O3 COCl2 PH3

SiH4 Si SiF4 SO2 C4H8S C4H4S C6H5CH WF6 C4H6O2 C2H3Cl

CXT-DM Instruction Ma nu al Rev. 1.6 Page 44 of 52

Model CXT-DM

Gas

C2H30

C2H2

C3H3N

Alcohols

Amines

NH3

AsF3

AsF5

AsH3

BF3

Br2

C4H6

Buten-1

C2H3O

n/a

40=340

40=75

n/d

40=170

n/d

C2H2

340=40

n/a

340=75

n/d

340=170

n/d

C3H3N

75=40

75=340

n/a

n/d

75=170

n/d

NH3

n/d

AsH3

n/d

100=0.01

n/d

n/a

n/d

Br2

n/d

n/a

n/d

C4H6

170=40

170=340

170=75

n/d

n/a

n/d

CS2

140=40

140=340

140=75

n/d

140=170

n/d

CO

n/d

Cl2

n/d

1=0.55

n/d

ClO2 (>10ppm)

n/d

1=0.18

n/d

ClO2 (=10ppm)

n/d

B2H6

n/d

100=0.013

n/d

0.15=0.2

n/d

C3H5OCl

50=40

50=340

50=75

n/d

50=170

n/d

C2H5OH

180=40

180=340

180=75

n/d

180=170

n/d

C2H5SH

n/d

C2H4

220=40

220=340

220=75

n/d

220=170

n/d

C2H4O

275=40

275=340

275=75

n/d

275=170

n/d

F2

n/d

1000=0

n/d

0.1=0

n/d

yes n/d

n/d

CH2O

330=40

330=340

330=75

n/d

330=170

n/d

GeH4

n/d

100=<1

n/d

0.2=0.14

n/d

N2H4

n/d

1000=0

n/d

200=0.04

n/d

0.1=0.1

n/d

H2 (ppm)

n/d

H2 (LEL)

n/d

100=0

n/d

HBr

n/d

1000=0

no

n/d

0.1=0.3

n/d

HCl

n/d

1000=0

no

n/d

0.1=0.3

n/d

HCN

n/d

1000=0

n/d

0.1=0

n/d

yes n/d

n/d

HF

n/d

1000=0

n/d

yes n/d

0.1=0

yes n/d

n/d

H2S

n/d

CH3OH

415=40

415=340

415=75

n/d

415=170

n/d

CH3SH

n/d

275=170

n/d

NO

n/d

NO2

n/d

O3

n/d

0.1=0.05

n/d

yes n/d

n/d

COCl2

n/d

1000=0

n/d

50=0.5

n/d

PH3

n/d

100=0.01

n/d

1=1

n/d

SiH4

n/d

100=<1

n/d

0.2=0.14

n/d

SO2

n/d

C4H6O2

200=40

200=340

200=75

n/d

200=170

n/d

C2H3Cl

200=40

200=340

200=75

n/d

200=170

n/d

Table 5 Cross Interference Table

n/a – not applicable n/d – no data

CXT-DM Instruction Ma nu al Rev. 1.6 Page 45 of 52

Model CXT-DM

Gas

CO2

CS2

CO

COS

CL2

CLO2

CLF3

B2H6

C2H6S

Si2H6

C3H5OCL

C2H5OH

F2

C2H3O

n/d

40=140

40=100

40=135

n/d

40=150

n/d

40=50

40=180

n/d

C2H2

n/d

340=140

340=100

340=135

n/d

340=150

n/d

340=50

340=180

n/d

C3H3N

n/d

75=140

75=100

75=135

n/d

75=150

n/d

75=50

75=180

n/d

NH3

n/d

300=8

n/d

1=-1

10%=-15

n/d

AsH3

5000=0

n/d

300=0

n/d

0.5=-0.04

n/d

0.2=0.15

n/d

5=yes n/d

n/d

Br2

n/d

300=0

n/d

1=2

1=6

n/d

C4H6

n/d

170=140

170=100

170=135

n/d

170=150

n/d

170=50

170=180

n/d

CS2

n/d

n/a

140=100

140=135

n/d

140=150

n/d

140=50

140=180

n/d

CO

n/d

n/a

n/d

1=0

n/d

200=0

n/d

Cl2

n/d

300=0

n/d

n/a

n/d

ClO2 (>10ppm)

n/d

300=0

n/d

3=1

n/a

n/d

ClO2 (=10ppm)

5000=0

n/d

1000=0

n/d

1=0.9

n/a

yes n/d

0.1=0

n/d

yes n/d

B2H6

5000=0

n/d

300=0

n/d

0.5=-0.05

n/d

n/a

n/d

5=yes n/d

n/d

C3H5OCl

n/d

50=140

50=100

50=135

n/d

50=150

n/d

n/a

50=180

n/d

C2H5OH

n/d

180=140

180=100

180=135

n/d

180=150

n/d

180=50

n/a

n/d

C2H5SH

n/d

300=5

n/d

1=-0.6

n/d

C2H4

n/d

220=140

220=100

220=135

n/d

220=150

n/d

220=50

220=180

n/d

C2H4O

n/d

275=140

275=100

275=135

n/d

275=150

n/d

275=50

275=180

n/d

F2

5000=0

n/d

1000=0

n/d

1=1.3

n/d

n/a

CH2O

n/d

330=140

330=100

330=135

n/d

330=150

n/d

330=50

330=180

n/d

GeH4

5000=0

n/d

300=0

n/d

0.5=-0.04

n/d

0.2=0.11

n/d

5=yes n/d

n/d

N2H4

5000=0

n/d

1000=0

n/d

1=0

n/d

H2 (ppm)

n/d

300=<30

n/d

1=0

n/d

H2 (LEL)

1000=0

n/d

50=6

n/d

5=0

n/d

HBr

5000=0

n/d

1000=0

n/d

5=1

n/d

yes n/d

n/d

HCl

5000=0

n/d

1000=0

n/d

5=1

n/d

1=yes n/d

n/d

HCN

5000=0

n/d

1000=0

n/d

5=-1

n/d

HF

5000=0

n/d

1000=0

n/d

1=0.4

n/d

yes n/d

0.1=0

n/d

yes n/d

H2S

n/d

300==1.5

n/d

1=˜-0.2

n/d

CH3OH

n/d

415=140

415=100

415=135

n/d

415=150

n/d

415=50

415=180

n/d

CH3SH

n/d

300=3

n/d

1=-0.4

n/d

NO

n/d

300=0

n/d

1=0

n/d

NO2

n/d

300=0

n/d

1=˜1

n/d

O3

5000=0

n/d

300=0

n/d

1=1.4

0.1=0.12

1=1(theory

n/d

0.1=0.07

COCl2

5000=0

n/d

1000=0

n/d

1=0

n/d

PH3

5000=0

n/d

300=0

n/d

0.5=-0.04

n/d

0.2=0.15

n/d

5=yes n/d

n/d

SiH4

5000=0

n/d

300=0

n/d

0.5=-0.04

n/d

0.2=0.11

n/d

5=yes n/d

n/d

SO2

n/d

300=<5

n/d

1=<0.5

n/d

C4H6O2

n/d

200=140

200=100

200=135

n/d

200=150

n/d

200=50

200=180

n/d

C2H3Cl

n/d

200=140

200=100

200=135

n/d

200=150

n/d

200=50

200=180

n/d

Table 5 Cross Interference Table (pg.2)

n/a – not applicable n/d – no data

CXT-DM Instruction Ma nu al Rev. 1.6 Page 46 of 52

Model CXT-DM

Gas

C2H4

C2H4O

CH2O

GeH4

N2H4

C-H's

C-H's (U)

H2

HBr

HCL

HCN

HF

I2

C2H3O

40=220

40=275

40=330

N/d

n/d

C2H2

340=220

340=275

340=330

N/d

n/d

C3H3N

75=220

75=275

75=330

N/d

n/d

NH3

100=0

n/d

N/d

n/d

200=4

n/d

5=-3

10=0

n/d

AsH3

n/d

1=0.4

n/d

%range=0

n/d

3000=0

n/d

5=0

10=0.1

4=0

n/d

Br2

100=0

n/d

N/d

n/d

100=0

n/d

5=0

10=0

n/d

C4H6

170=220

170=275

170=330

N/d

n/d

CS2

140=220

140=275

140=330

N/d

n/d

CO

100=<100

n/d

N/d

n/d

100=<60

n/d

5=0

10=<2

n/d

Cl2

100=0

n/d

N/d

n/d

100=0

n/d

5=0

10=0

n/d

ClO2 (>10ppm)

100=0

n/d

N/d

n/d

100=0

n/d

5=0

10=0

n/d

ClO2 (=10ppm)

n/d

1=0

n/d

%range=0

n/d

1%=0

n/d

B2H6

n/d

1=0.53

n/d

%range=0

n/d

3000=0

n/d

5=0

10=0.13

4=0

n/d

C3H5OCl

50=220

50=275

50=330

N/d

n/d

C2H5OH

180=220

180=275

180=330

N/d

n/d

C2H5SH

100=0

n/d

N/d

n/d

1%=<15

n/d

5=0

10=0

n/d

C2H4

n/a

220=275

220=330

n/d

C2H4O

275=220

n/a

275=330

n/d

F2

n/d

%range=0

n/d

1%=0

n/d

5=0

1=-3

3=0

n/d

CH2O

330=220

330=275

n/a

n/d

GeH4

n/d

n/a

n/d

%range=0

n/d

3000=0

n/d

5=0

10=1

4=0

n/d

N2H4

n/d

n/a

%range=0

n/d

1000=0

n/d

5=0.1

n/d

3=0

n/d

H2 (ppm)

100=˜80

n/d

n/a

n/d

5=0

10=˜3

n/d

H2 (LEL)

yes n/d

n/d

n/a

n/d

10=0

n/d

HBr

n/d

%range=0

n/d

1%=0

n/a

1=1

15=1

3=0

n/d

HCl

n/d

1=n/d

n/d

%range=0

n/d

1%=0

1=1

n/a

15=1

3=0

n/d

HCN

n/d

%range=0

n/d

1000=0

n/d

5=0

n/a

3=0

n/d

HF

n/d

1=0

n/d

%range=0

n/d

1%=0

n/d

5=3.3

n/d

n/a

n/d

H2S

100=0

n/d

1%=<5

n/d

5=0

10=0

n/d

CH3OH

415=220

415=275

415=330

n/d

CH3SH

100=0

n/d

1%=<10

n/d

5=0

10=0

n/d

NO

100=0

n/d

100=0

n/d

5=<1

10=0

n/d

NO2

100=0

n/d

100=0

n/d

5=0

10=0

n/d

O3

n/d

1%=0.003

n/d

10=0

10=0.03

5=0

yes n/d

COCl2

n/d

%range=0

n/d

1%=0

n/d

5=0

3=0

n/d

PH3

n/d

1=0.4

n/d

%range=0

n/d

3000=0

n/d

5=0

10=0.1

4=0

n/d

SiH4

n/d

1=1.0

n/d

%range=0

n/d

3000-=0

n/d

5=0

10=1

4=0

n/d

SO2

100=0

n/d

100=0

n/d

5=0

10=<5

n/d

C4H6O2

200=220

200=275

200=330

n/d

C2H3Cl

200=220

200=275

200=330

n/d

Table 5 Cross Interference Table (pg.3)

n/a – not applicable n/d – no data

CXT-DM Instruction Ma nu al Rev. 1.6 Page 47 of 52

Model CXT-DM

Gas

HSe

H2S

C3H8O

CH4

CH3OH

C4H8O

CH3SH

NO

N2

NO2

O3

COCL2

PH3

C2H3O

n/d

40=415

n/d

40=275

n/d

C2H2

n/d

340=415

n/d

340=275

n/d

C3H3N

n/d

75=415

n/d

75=275

n/d

NH3

n/d

15=30

n/d

35=6

n/d

5=-1

n/d

AsH3

0.05=0.005

1=0

n/d

100%=0

n/d

0.1=0.11

Br2

n/d

15=-1.5

n/d

35=0

n/d

5=˜10

n/d

C4H6

n/d

170=415

n/d

170=275

n/d

CS2

n/d

140=415

n/d

140=275

n/d

CO

n/d

15=<0.3

n/d

35==7

n/d

5=0.5

n/d

Cl2

n/d

15=-0.75

n/d

35=0

n/d

5=˜5

n/d

ClO2 (>10ppm)

n/d

15=0.25

n/d

35=0

n/d

5=1.66

n/d

ClO2 (=10ppm)

n/d

10=-0.015

n/d

yes n/d

n/d

B2H6

0.05=0.006

1=0

n/d

100%=0

n/d

0.1=0.14

C3H5OCl

n/d

50=415

n/d

50=275

n/d

C2H5OH

n/d

180=415

n/d

180=275

n/d

C2H5SH

n/d

1:03

n/d

5=8

35=<6

n/d

5=-1.5

n/d

C2H4

n/d

220=415

n/d

220=275

n/d

C2H4O

n/d

275=415

n/d

275=275

n/d

F2

n/d

1=-1.5

n/d

100%=0

1=0.05

0.1=0.2

n/d

CH2O

n/d

330=415

n/d

330=275

n/d

GeH4

0.05=0.005

1=0

n/d

100%=0

n/d

0.1=0.13

N2H4

n/d

1=0.1

n/d

100%=0

1=-0.25

0.1=-0.1

n/d

0.3=0.1

H2 (ppm)

n/d

15=<3

n/d

35=˜10

n/d

5=0

n/d

H2 (LEL)

n/d

yes n/d

1%=0

n/d

yes n/d

n/d

10=0

n/d

HBr

0.1=0

10=2.75

n/d

100%=0

n/d

0.1=0

0.1=0.3

HCl

0.1=0

10=2.75

n/d

100%=0

n/d

0.1=0

0.1=0.3

HCN

n/d

10=0

n/d

100%=0

10=-12

0.1=0

n/d

0.3=0

HF

n/d

10=0

n/d

100%=0

10˜0.1

n/d

0.1=0

H2S

n/d

n/a

n/d

2:01

35=<2

n/d

5=-0.5

n/d

CH3OH

n/d

n/a

n/d

415=275

n/d

CH3SH

n/d

1:02

n/d

n/a

35=<4

n/d

5=-1.0

n/d

NO

n/d

15=˜5

n/d

100=0

n/d

5=<1.5

n/d

NO2

n/d

15=-0.75

n/d

35=0

n/d

n/a

n/d

O3

n/d

1=-.015

n/d

10=0

100%=0

1=0.7

n/a

n/d

0.3=0.03

COCl2

n/d

1=0

n/d

100%=0

n/d

n/a

0.3=0

PH3

0.05=0.005

1=0

n/d

100%=0

n/d

n/a

SiH4

0.05=0.005

1=0

n/d

100%=0

n/d

0.1=0.13

SO2

n/d

15=0

n/d

35=0

n/d

5=˜-5

n/d

C4H6O2

n/d

200=415

n/d

200=275

n/d

C2H3Cl

n/d

200=415

n/d

200=275

n/d

Table 5 Cross Interference Table (pg.4)

n/a – not applicable n/d – no data

CXT-DM Instruction Ma nu al Rev. 1.6 Page 48 of 52

Model CXT-DM

Gas

PF3

SiH4

Si

SiF4

SO2

C4H8S

C4H4S

C6H5CH3

WF6

C4H6O2

C2H3CL

C2H5SH

C6H5CH3

C2H3O

n/d

40=45

n/d

40=200

n/d

40=55

C2H2

n/d

340=45

n/d

340=200

n/d

340=55

C3H3N

n/d

75=45

n/d

75=200

n/d

75=55

NH3

n/d

5=-0.5

n/d

AsH3

n/d

1=0.56

n/d

2=0

n/d

Br2

n/d

5=-0.1

n/d

C4H6

n/d

170=45

n/d

170=200

n/d

170=55

CS2

n/d

140=45

n/d

140=200

n/d

140=55

CO

n/d

5=0

n/d

Cl2

n/d

5=-0.05

n/d

ClO2 (>10ppm)

n/d

5=-0.016

n/d

ClO2 (=10ppm)

n/d

B2H6

n/d

1=0.72

n/d

2=0

n/d

C3H5OCl

n/d

50=45

n/d

50=200

n/d

50=55

C2H5OH

n/d

180=45

n/d

180=200

n/d

180=55

C2H5SH

n/d

5=<3

n/d

n/a

n/d

C2H4

n/d

220=45

n/d

220=200

n/d

220=55

C2H4O

n/d

275=45

n/d

275=200

n/d

275=55

F2

n/d

2=0

n/d

CH2O

n/d

330=45

n/d

330=200

n/d

330=55

GeH4

n/d

1=1

n/d

2=0

n/d

N2H4

n/d

2=0

n/d

H2 (ppm)

n/d

5=0

n/d

H2 (LEL)

n/d

2=0

n/d

HBr

n/d

5=2.5

n/d

HCl

n/d

5=2.5

n/d

HCN

n/d

2=0

n/d

HF

yes n/d

n/d

3=4(theory)

yes n/d

n/d

yes n/d

n/d

H2S

n/d

5=<1

n/d

3=1

n/d

CH3OH

n/d

415=45

n/d

415=200

n/d

413=55

CH3SH

n/d

5=<2

n/d

2=1

n/d

NO

n/d

5=0

n/d

NO2

n/d

5=-0.025

n/d

O3

n/d

1=0.015

n/d

2=0

n/d

COCl2

n/d

2=0

n/d

PH3

n/d

1=0.56

n/d

2=0

n/d

SiH4

n/d

n/a

n/d

2=0

n/d

SO2

n/d

n/a

n/d

C4H6O2

n/d

200=45

n/d

n/a

200=200

n/d

200=55

C2H3Cl

n/d

200=45

n/d

200=200

n/a

n/d

200=55

Table 5 Cross Interference Table (pg.5)

n/a – not applicable n/d – no data

CXT-DM Instruction Ma nu al Rev. 1.6 Page 49 of 52

Model CXT-DM

92C-240200-000

CXT-DM-H2S Intelligent Tra nsmitter Module

92C-XX0200-YYY

CXT-DM Intelligent Transmitter Module for Toxic Gas Sensors (where xx=Gas Code, and YYY=Range)

371-

XXXX00-XXX

Replacement Plug-in sensor (Refer to Table 3 S en sor Speci fi c Data)

500-005180-100

CXT Smart Battery Terminal Board

976-0BP303-012

Plug-in Battery Pack 12V 2200mAh (Rechargeable)

976-0BP303-290

Plug-In Battery Pack 12V 2900mAh (Rechargeable)

360-0265500-000

Lithium Primary 3.6V ‘C’ size battery (Not rechargeable)

360-036500-000

Battery, Lithium 3.6V 'D'-size (Not rechargeable)

960-202200-000

Condensation prevention packet (For condulet, replace annually)

602-003870-000

Tri-C Size Battery Holder Assembly

602-004402-000

D-Sized Battery Pack Assembly ( for 5 cell, replaceable, non-rechargeable)

613-120000-700

Sensor Splash Guard with integral Cal Port

602-003803-000

CXT-DM Splashguard Adapter Assembly

602-003803-200

CXT-DM H2S Splashguard Adapter Assembly

943-002273-000

Harsh Environment Sensor Guard

327-000000-000

Programming Magnet

943-000006-132

Threaded Calibration Adapter

943-000000-000

Calibration Wind Guard

943-01747-T05

Calibration Adapter for highly reactive gases

943-050000-132

Span Gas Kit: Includes calibration adapter, span gas humidifier, 500cc/min fixed flow regulator, and carrying case. (Not including gas).

943-050000-HRG

Highly Reactive Gas Span Gas Kit (Used for NH3, Cl2, HCl, HBr, etc.)

See Detcon

Span Gases – various

943-05AM00-000

500 cc/min Fixed Flow Regulator for span gas bottle

897-850800-010

NEMA 7 Aluminum Condulet Base

897-850400-010

NEMA 7 Aluminum Condulet Solid Cover

897-850500-010

NEMA 7 Aluminum Condulet w/Window Cover

897-860401-316

316SS Mini Condulet Extended Cover

897-860800-316

316SS Mini Condulet base

960-202200-000

Condensation prevention packet (For condulet, replace annually)

943-004365-000

Wireless Sensor Mounting Plate (for use with Standard Al condulet)

500-005180-100

CXT Smart Battery Terminal Board

303-734231-000

Insertion tool, CAGE Clamp Connector

9.4 Spare Parts, Sensor Accessories, Calibr ation Equipm ent

Part Number

Spare Parts

Sensor Accessories

Part Number

Calibration Accessories

Optional Accessories

CXT-DM Instruction Ma nu al Rev. 1.6 Page 50 of 52

Model CXT-DM

Revision

Date

Changes made

Approval

0.0

03/31/12

Release

LU

0.1

12/04/12

Adding note requiring removal of sensor assembly to nonhazardous location to install or replace batteries

BM

1.2

2/21/13

Updated spare parts list, drawings

LBU

1.3

9/30/13

Added section 2.1 Hazardous Location Guidelines

BM

1.4

01/20/14

Add Calibration Wind Guard to Calibration Procedures

BM

1.5

02/10/14

Add detail to battery installation

BM

1.6

05/29/14

Updated Approval Label

BM

9.5 Revision Log

CXT-DM Instruction Ma nu al Rev. 1.6 Page 51 of 52

Model CXT-DM

Shipping Address: 4055 Technology Forest, Suite 100, The Woodlands, Texas 77381

Phone: 888.367.4286, 281.367.4100 • Fax: 281.292.2860 •www.detcon.com •

This page left intentionally blank

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

CXT-DM Instruction Ma nu al Rev. 1.6 Page 52 of 52

Detcon CXT-DM User Manual

Specifications and Main Features

Frequently Asked Questions

User Manual

Table of Contents

Table of Figur es

List of Tables

1. Introduction

1.1 Description

Electrochemical Sensor Technology

1.2 Modular Design

1.2.1 CXT-DM Intelligent Transmitter Module

1.2.2 Field Replaceable Sensor

1.3 CXT Wireless Network

1.4 Battery Pack Options

1.4.1 Detcon’s Smart Battery Pack

Quad Battery Charger (Optional)

1.4.2 Tri-C Lithium Battery Pack

2. Installation

2.1 Hazardous Locations Installation Guidelines for Safe Use

2.2 Sensor Placement

2.3 Sensor Cont aminants and Interference

Cross-Interference Data T ab le

2.4 Sensor Mounting

2.5 Electrica l Installation

Applying power to the unit

2.6 Initial Start Up

2.6.1 Toxic Gas Sensors

Initial Operational Tests

Material Requirements

2.6.2 O2 Deficiency Sensors

3. Operation

3.1 Operator Interface

Normal Operation

Calibration Mode

Program Mode

Software Flowchart

3.2 Normal Operation

3.3 Calibration Mode

3.3.1 AutoZero

Material Requirements:

Zero Cal . . . Setting Zero . . . Zero Saved ( each wil l scro ll twice)

3.3.2 AutoSpan

Material Requirements:

3.4 Program M ode

Navigating Program Mode

3.4.1 View Sensor Status

Main processor firmware version

Co-processor firmware version

The menu item appears as: “Cp App ##.##”

Rf firmware version

Rf Software version

Modbus ID

Serial Number

RF Channel

Network ID

Range

AutoSpan Level

Temperature Compensation Level

Last Cal

Sensor Life

Temperature

3.4.2 Set Detection Range

3.4.3 Set Autospan Level

3.4.4 Bump Test

3.4.5 Restore Defaults

3.4.6 Set RF Channel

3.4.7 Set Modbus ID

3.5 Fault Diagnostic/Failsafe Feature

4. Modbus™ Communications

4.1 General Modbus™ De scr ip ti on

4.1.1 Modbus™ Exceptions

4.1.2 Modbus™ Broadcast Requests

4.2 Modbus™ Register Map & Description

4.2.1 CXT Sensor Registers

4.2.1.1 Sensor Faults – Register 0005

4.2.2 CXT Transceiver Registers

4.2.2.1 Battery Info – Multiple Registers

4.2.2.2 Wireless Controller Version

4.2.2.3 Register – Update Rate