Detcon FP-624D User Manual

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INSTRUCTION MANUAL

DETCON, Inc.

April 23, 2012

• Document #

3598

• Revision

1.2

Detcon Model FP-624D

PGM 1

MODEL FP-624DHOUSTON,TEXAS

MicroSafe LEL Gas Sensor

ALM ALM

FLT 1 2 CAL

PGM 2

FP-624D Combustible Gas Sensor

(0-100% LEL)

4055 Technology Forest Blvd, Suite 100,

The Woodlands, Texas 77381

Ph.281.367.4100 / Fax 281.298.2868

www.detcon.com

This page left intentionally blank

Model FP-624D

FP-624D InstructionManual ii

Model FP-624D

Table of Contents

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

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

1.2 Modular Mechanical Design...........................................................................................................3

1.3 Relay Outputs ................................................................................................................................5

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

2.1 Operational Guidelines for Safe Use...............................................................................................6

2.2 Sensor Placement ...........................................................................................................................6

2.3 Sensor Contaminants and Interference............................................................................................7

2.4 Mounting Installation .....................................................................................................................8

2.5 Electrical Installation......................................................................................................................8

2.6 Field Wiring...................................................................................................................................9

2.7 Remote Mounting Installation......................................................................................................11

2.7.1 Bridge Voltage Adjustment......................................................................................................11

2.8 Initial Start Up .............................................................................................................................12

3. Operation ............................................................................................................................................. 13

3.1 Programming Magnet Operating Instructions................................................................................13

3.2 Operator Interface ........................................................................................................................14

3.3 Normal Operation ........................................................................................................................16

3.4 Calibration Mode (AutoSpan).......................................................................................................16

3.4.1 AutoZero .................................................................................................................................16

3.4.2 AutoSpan.................................................................................................................................17

3.5 Program Mode .............................................................................................................................18

3.5.1 View Sensor Status..................................................................................................................19

3.5.2 Set AutoSpan Level .................................................................................................................21

3.5.3 Set Gas Factor.......................................................................................................................... 21

3.5.4 Set Cal Factor ..........................................................................................................................23

3.5.5 Set Bridge Voltage...................................................................................................................23

3.5.6 Signal Output Check................................................................................................................ 24

3.5.7 Restore Factory Defaults..........................................................................................................24

3.5.8 Set Serial ID ............................................................................................................................25

3.5.9 Alarm 1 and 2 Settings.............................................................................................................26

3.5.10 Fault Settings.......................................................................................................................26

3.6 Program Features.........................................................................................................................27

3.6.1 Operational Features ................................................................................................................ 27

3.6.2 Fault Diagnostic/Failsafe Features............................................................................................28

4. RS-485 ModbusTMProtocol..................................................................................................................30

5. Service and Maintenance......................................................................................................................32

6. Troubleshooting Guide.........................................................................................................................34

7. Customer Support and Service Policy................................................................................................... 37

8. FP-624D Sensor Warranty....................................................................................................................38

9. Appendix..............................................................................................................................................39

9.1 Specifications...............................................................................................................................39

9.2 Spare Parts, Sensor Accessories, Calibration Equipment...............................................................41

9.3 Revision Log................................................................................................................................ 42

FP-624D InstructionManual iii

Model FP-624D

Shipping Address:

4055 Technology Forest Blvd, Suite 100,

The Woodlands Texas 77381

List of Figures

Figure 1 Sensor Assembly Front View............................................................................................................ 1

Figure 2 Sensor Cell Construction .................................................................................................................. 2

Figure 3 Wheatstone Bridge ........................................................................................................................... 2

Figure 4 Response Curves.............................................................................................................................. 3

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

Figure 6 Transmitter Module.......................................................................................................................... 4

Figure 7 Field Replaceable Combustible Gas Sensor....................................................................................... 4

Figure 8 Base Connector Board ...................................................................................................................... 5

Figure 9 Typical Outline and Mounting Dimensions....................................................................................... 8

Figure 10 Typical Installation......................................................................................................................... 9

Figure 11 Sensor Connector PCB ..................................................................................................................10

Figure 12 Remote Sensor Wiring Diagram.....................................................................................................11

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

Figure 14 Magnetic Programming Switches...................................................................................................13

Figure 15 FP-624D Software Flowchart.........................................................................................................15

Figure 16 Replaceable Combustible Gas Sensor ...........................................................................................34

Figure 17 Plug-in Sensor (Bottom View).......................................................................................................34

List of Tables

Table 1 Wire Gauge vs. Distance...................................................................................................................10

Table 2 Gas/Cal Factors.................................................................................................................................22

Table 3 Modbus Registers .............................................................................................................................30

Table 4 Notation Text String Description.......................................................................................................31

FP-624D InstructionManual iv

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

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

Model FP-624D

1. Introduction

1.1 Description

Detcon Model FP-624D combustible gas sensors are non-intrusive “Smart” sensors designed to detect and monitor combustible gases in air. Range of detection is 0-100% LEL (Lower Explosive Limit). The sensor features an LED display of current reading, fault, and calibration status. The sensor is equipped with standard analog 4-20mA, ModbusTMRTU output, and 3 relay contact outputs. A primary feature of the sensor is its method of automatic calibration, which guides the user through each step via fully scripted instructions displayed on the LED display.

The microprocessor-supervised electronics are packaged as a plug-in replaceable Transmitter Module that is housed in an explosion proof junction box. The Transmitter Module includes a four character alpha/numeric LED used to display sensor readings, and the sensor’s menu driven features when the hand-held programming magnet is used.

PGM 1

MODEL FP-624DHOUSTON,TEXAS

MicroSafe LEL GasSensor

ALM ALM

FLT 1 2 CAL

PGM 2

Figure 1 Sensor Assembly Front View

Catalytic Bead (Pellistor) Sensor Technology

The sensor technology is a poison-resistant catalytic bead type. Catalytic bead sensors show a strong response to a long list of combustible gases. The sensor is supplied as a matched-pair of detector elements mounted in a plug-in replaceable module. One bead is a catalytically active detector and the other is a non-active reference detector. Each detector consists of a fine platinum wire coil embedded in aluminum oxide. A catalytic mixture is applied to the active detector while the reference detector is treated so that oxidation of the gas does not occur. The technique is referred to as non-selective and may be used to monitor most any combustible gas. Detcon catalytic bead sensors are specifically designed to be resistant to poisons such as sulfides, chlorides, and silicones. The sensors are characteristically stable and capable of providing reliable performance for periods exceeding 5 years in most industrial environments.

FP-624D InstructionManual Rev. 1.2 Page 1 of 42

Model FP-624D

Platinum Wire

Catalyst

Construction

of Detector

Bead

Alumina Bead

Catalytic Beads

Main Housing Insert

Printed Circuit Board Gold Plated Pins

Figure 2 Sensor Cell Construction

Principle of Operation

Method of detection is by diffusion/adsorption. Air and combustible gases pass through a sintered stainless steel filter and contact the heated surface of both the active and reference detectors. The surface of the active detector promotes oxidation of the combustible gas molecules while the reference detector has been treated not to support this oxidation. The reference detector serves as a means to maintain zero stability over a wide range of temperature and humidity.

When combustible gas molecules oxidize on the surface of the active detector, heat is generated, and the resistance of the detector changes. Electronically, the detectors form part of a balanced bridge circuit. As the active detector changes in resistance, the bridge circuit unbalances. This change in output is conditioned by the amplifier circuitry, which is an integral part of the sensor design. The response and clearing characteristics of the sensor are rapid and provide for the continuous and accurate monitoring of ambient air conditions.

Sensor

Cell

Compensator / Reference Bead

Input

Voltage

Zero

Adjust

Detector /

Active Bead

Output

Figure 3 Wheatstone Bridge

Performance Characteristics

The detector elements maintain good sensitivity to combustible gas concentrations in the Lower Explosive Limit (LEL) range, as shown in the response curves in Figure 4. However, for gas concentrations significantly above the LEL range (100% LEL = 5% by volume Methane), the bridge output begins to decrease. Ambiguous readings above the LEL range dictate that alarm control logic be of the latching type, wherein alarms are held in the “ON” position until reset by operations personnel.

FP-624D InstructionManual Rev. 1.2 Page 2 of 42

Figure 4 Response Curves

RS-4854-

20mA

Display

Control

Pre-Amp

Power Supply

1.2 Modular Mechanical Design

The Model FP-624D Sensor Assembly is completely modular and is made up of four parts:

1) FP-624D Plug-in Transmitter

2) Field Replaceable Combustible Gas Sensor

3) Connector PCB

4) Splash Guard

ModelFP-624D

FP-624D Plug-in Transmitter

The Plug-in Transmitter Module is a microprocessor-based package that plugs into the connector board located in the explosion proof junction box. Circuit functions include extensive I/O circuit protection, sensor preamplifier, sensor temperature control, on-board power supplies, microprocessor, LED display, magnetic programming switches, a linear 4-20mA DC output, and a Modbus RTU output. Magnetic program switches located above and below the LED Display are activated via a hand-held magnetic programming tool, thus allowing non-intrusive operator interface with the Transmitter Module. Calibration can be accomplished without declassifying the area. Electrical classifications are Class I, Division 1, Groups B C D.

Analog 4-20mA Out

Plug-In

Sensor

Element

Temperature

Micro-

Processor

Figure 5 Circuit Functional Block Diagram

I/O

Circuit

Protection

Relays Out

Modbus RTU

Power In

FP-624D Instruction Manual Rev. 1.2 Page 3 of 42

PGM 1

MODEL FP-624DHOUSTON,TEXAS

Model FP-624D

MicroSafe LEL Gas Sensor

ALM ALM

FLT 1 2 CAL

PGM 2

Figure 6 Transmitter Module

The transmitter module includes four LED status indicators (see Figure 3). These indicators are labeled FLT, ALM1, ALM2 and CAL. The ALM1 and ALM2 LEDs are illuminated when the sensor is above the corresponding alarm threshold. The FLT LED is illuminated when the sensor is in fault. The CAL LED is illuminated solid when the sensor is completing an AutoZero or AutoSpan calibration. If the sensor is not being calibrated, the CAL LED will flash each time the sensor answers a poll request from a Modbus

master.

Field ReplaceableSensor

The Detcon combustible gas sensor is a field proven, replaceable type sensor. It can be accessed and replaced in the field by removing the threaded insert from the lower housing and unplugging the replaceable sensor. The Detcon combustible gas sensor has an infinite shelf life and is supported by a 2 year warranty.

Replaceable Sensor

Threaded Insert

O-ring

Main Housing

Figure 7 Field Replaceable Combustible Gas Sensor

NOTE: The Field Replaceable Combustible Gas Sensor housing is constructed from 316 Stainless Steel in order to maximize corrosion resistance in harsh environments.

Base ConnectorPCB

The base connector board is mounted in the junction box. The connector board includes lug-less terminal connections for incoming power, Modbus, and mA output, and connections for the Combustible Gas Replaceable Sensor. Terminals for the 3 common and normally open/normally closed relay outputs are also located on the base connector board.

FP-624D InstructionManual Rev. 1.2 Page 4 of 42

Model FP-624D

NOTE

: The relay outputs will not activate during the first 60 seconds after sensor power up.

Relays

Customer

Wiring

Wiringto

Figure 8 Base Connector Board

1.3 Relay Outputs

The FP-624D includes three 5A Form C relay outputs. Two of these relays are dedicated to alarm outputs, and the third is used to indicate when the sensor is in fault. The common and normally closed contacts on the alarm relays are connected when the gas concentration is below the alarm threshold. If the concentration exceeds the alarm threshold for more than five seconds, then the common and normally open contacts will be connected.

The common and normally closed contacts on the fault relay are connected when the sensor is not in fault. If the sensor experiences a fault condition for more than five seconds, then the common and normally open contacts will be connected.

The common and either the normally open or the normally closed contacts from the alarm and fault relays are connected to terminals on the base connector board. A jumper near each relay is used to select whether the normally open or normally closed contact is connected to the terminal on the base connector board.

The relays can be configured to operate in Energized Mode. In this mode, the common and normally open contacts are connected when the gas is below the alarm threshold (alarm relays) or is not in fault (fault relay). This mode allows for fail-safe operation of the sensor. If the power to the sensor fails or the cable to the sensor I/O is disconnected, then the common and normally open contacts will no longer be connected.

The alarm and fault relays can be configured as either latching or non-latching. In non-latching mode, the relay is deactivated as soon as the sensor alarm or fault condition is cleared. In latching mode, the relay remains active even after the alarm or fault condition has cleared. Once activated, the relay can only be deactivated by swiping a magnetic programming tool above the PGM1 or PGM2 mark on the FP-624D face plate.

The alarm relays can be configured for ascending or descending mode. In ascending mode the relay will be activated when the concentration is above the alarm threshold. This is the most common mode of operation for the FP-624D. The alarm relays can also be activated in descending mode. In this mode, the alarm relays will activate when the concentration is below the alarm threshold.

This allows the sensor cell to stabilize and begin outputting an accurate reading.

FP-624D InstructionManual Rev. 1.2 Page 5 of 42

Model FP-624D

NOTE:

Methane and Hydrogen are lighter than air. Most other combustible gases are

heavier

2. Installation

2.1 Operational Guidelines for Safe Use

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

2. Ensure that the sensor is properly mounted in a vertical orientation with sensor facing down. Avoid use of excessive Teflon Tape, or any type of non-conductive pipe thread coating on the NPT threaded connection. All NPT connections should remain grounded to the junction box.

3. Use ¾” NPT plugs properly rated for hazardous locations to block any unused connections.

4. Removal of the Junction box cover or threaded sensor housing (612-820000-000) violates the Ex Proof protection method and hence power must be removed from the sensor prior to its safe removal.

5. Ensure that the threaded insert and plug-in sensor are installed during operation. The threaded insert should be secured tightly to the sensor housing. Removal of the threaded insert violates the Ex Proof protection method and hence power must be removed from the sensor prior to its safe removal.

6. Proper precautions should be taken during installation and maintenance to avoid the build-up of static charge on the plastic components of the sensor. These include the splashguard and splashguard adapter.

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

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

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) Maintenance access (6) Additional Placement Considerations

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.

than air. Compare the molecular weight, density, or specific gravity of the target gas(es) with that of air to determine appropriate placement.

FP-624D InstructionManual Rev. 1.2 Page 6 of 42

Model FP-624D

NOTE:

In all installations the gas sensor should point straight down (refer to

Figure

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 approach 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.

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

Additional Placement Considerations

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

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 Contaminants and Interference

Detcon combustible gas sensors may be adversely affected by exposure to certain airborne substances. Loss of sensitivity or corrosion may be gradual if such materials are present in sufficient concentrations.

The performance of the detector elements may be temporarily impaired during operation in the presence of substances described as inhibitors. Inhibitors are usually volatile substances containing halogen compounds. Inhibitors include halide compounds such as Cl2, ClO2, F2, HF, HCl, Br2, vinyl chloride, and methyl chloride. Inhibition is typically a temporary effect and the detectors generally recover after short periods of operation back in clean air.

Some background gases may act as poisoning agents and have a more damaging effect on the sensor. Although the sensor is designed to be poison resistant, it does have physical limits. Poisoning gases deactivate the active detector’s catalytic ability and cause a permanent reduction in the span sensitivity. Examples of

FP-624D InstructionManual Rev. 1.2 Page 7 of 42

Model FP-624D

NOTE:

Do not use Teflon Tape or any other

type of Pipe Thread material on the ¾” threads

typical poisons are: silicone oils and greases, siloxanes (HMDS), H2S, anti-knock petrol additives, and phosphate esters. Activated carbon filters can be used to provide additional protection from poisoning in most cases.

The presence of such inhibitors and poisons in an area does not preclude the use of this sensor technology, although it is likely that the sensor lifetime will be shorter as a result. Use of this sensor in these environments may require more frequent calibration checks to ensure safe system performance.

2.4 Mounting Installation

The FP-624D should be vertically oriented so that the sensor points straight downward. The explosion-proof enclosure or junction box would then typically be mounted on a wall or pole (See Figure 9). Detcon provides a selection of standard junction boxes in both Aluminum and Stainless Steel.

unless the unit is mounted in a severe or harsh environment. Metal-on-metal contact must be maintained to provide a solid electrical ground path. If Teflon Tape is used the Sensor must be externally grounded using a ground strap.

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

6.985"

" mounting holes

6.125"

5.5"

2.1"

0.5"

NPT Ports

5.25"

8-32 tapped ground point

LEL Sensor

Splash Guard

Figure 9 Typical Outline and Mounting Dimensions

4.6"

Wall (or other

mounting surface)

2.5 Electrical Installation

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

FP-624D InstructionManual Rev. 1.2 Page 8 of 42

Model FP-624D

NOTE:

If a conduit run exits the secondary port, repeat the installation techniqu

e shown in

NOTE:

A conduit seal is typically required to be located within 18" of the J

Box and Sensor

NOTE:

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

NOTE:

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

Proper electrical installation of the gas sensor is critical for conformance to Electrical Codes and to avoid damage due to water leakage. Refer to Figure 10 and Figure 11 for proper electrical installation.

Figure 10.

In Figure 10, the drain allows H2O condensation inside the conduit run to safely drain away from the sensor assembly. The electrical seal fitting is required to meet the National Electrical Code per NEC Article 500-3d (or Canadian Electrical Code Handbook Part 1 Section 18-154). Requirements for locations of electrical seals are covered under NEC Article 501-5. Electrical seals 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.

Assembly. Crouse Hinds type EYS2, EYD2 or equivalent are suitable for this purpose.

the enclosure.

Conduit

"T"

Drain

EYS Seal Fitting

PGM 1

MODEL TP-624DHOUSTON,TEXAS

MicroSafe H2S Gas Sensor

ALM ALM

FLT 1 2 CAL

PGM 2

Figure 10 Typical Installation

Supplies one ¾” NPT male plug with each J-box enclosure. If connections are other than ¾” NPT, use an appropriate male plug of like construction material.

2.6 Field Wiring

Detcon Model FP-624D combustible gas sensor assemblies require up to five conductor connections between power supplies and host electronic controller. Wiring designations are DC+, DC-, MA (sensor signal), Modbus A and Modbus B. If the MA signal is not needed, its terminal may be left unconnected. A 250 ohm load resistor is needed on the 4-20 mA line when it is not being used. The maximum wire length between sensor

FP-624D InstructionManual Rev. 1.2 Page 9 of 42

ModelFP-624D

Over

Current

0.723mm

700

2080

3A200.812mm

1120

3350

5A181.024mm

1750

5250

7A161.291mm

2800

8400

10A141.628mm

4480

13,440

20A

NOTE 1:

Wiring table is based on stranded tinned copper wire and is designed to serve as a

NOTE 2:

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

NOTE 3:

The supply of power shou

ld be from an isolated source with over

current protection

NOTE 4:

A 250 ohm load resistor is need

ed on the 4

20 mA line when it is not being used.

and 24VDC source is shown in the Table below. The maximum wire size for termination in the Junction Box is 14 AWG.

Table 1 Wire Gauge vs. Distance

AWG Wire Dia. Meters Feet

reference only.

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

as stipulated in Table 1 Wire Gauge vs. Distance.

Terminal Connections

CAUTION: Do not apply System power to the sensor until all wiring is properly terminated. Refer

to Section 2.8 Initial Start Up

Protection

Alarm 2

Black

Blue

Yellow

Alarm 1

Wiringto

LEL Sensor

Fault

Customer

Wiring

Power(+ -) 4-20mA

RS-485 (A,B)

White

Figure 11 Sensor Connector PCB

a) Remove the junction box cover and unplug the Transmitter Module. Identify the terminal blocks for

customer wire connections.

FP-624D Instruction Manual Rev. 1.2 Page 10 of 42

Model FP-624D

NOTE

: A 6

-32or 8-32 threaded exterior ground point is provided on most junction boxes for

b) Observing correct polarity, terminate the field wiring (DC+, DC-, MA, A, and B) to the sensor assembly

wiring in accordance with the detail shown in Figure 11.

c) Trim all exposed wire leads if they are not permanently landed in the terminal block.

d) Plug the Transmitter Module into the connector PCB and replace the junction box cover.

an external ground. If the Sensor Assembly is not mechanically grounded, an external ground strap must be used to ensure that the sensor is electrically grounded.

2.7 Remote Mounting Installation

Some sensor mounting applications require that the gas sensor head be remotely mounted away from the sensor transmitter. This is usually true in instances where the gas sensor head must be mounted in a location that is difficult to access. Such a location creates problems for maintenance and calibration activities. Detcon provides the FP-624D sensor in a remote-mount configuration in which the sensor (Model FP-624D-RS) and the transmitter (Model FP-624D-RT) are provided in their own condulet housing and are interfaced together with a three conductor cable. There is a limit 0.5 ohm maximum resistance drop per wire over the separation distance.

AWG Maximum Separation (feet)

20 50 18 75 16 125 14 175

Reference Figure 12 for wiring diagram. Also note the jumper that is required on the remote sensor connector board. Failure to install this jumper will cause a sensor fault condition.

Figure 12 Remote Sensor Wiring Diagram

2.7.1 Bridge Voltage Adjustment

When a sensor is remote mounted, consideration must be given to the lengths of cable used and how it affects the sensor bridge voltage. Differing lengths of cables will have varying amounts of resistance which will shift the sensor bridge voltage. Because of this, the bridge voltage will need to be adjusted after initial power up.

FP-624D InstructionManual Rev. 1.2 Page 11 of 42

Model FP-624D

NOTE

: Refer to section 3.5.5

to set the sensor bridge voltage.

NOTE

: The 4

20mA signal is held constant at 4mA for the first two

minutes after power up.

NOTE

: Do not use calibration gases in Nitrogen background gas mixtures. This will cause

This adjustment is only required after initial installation and will not be necessary thereafter, except in the event of replacement of the plug-in sensor. Refer to section 3.5.5 to perform this adjustment.

2.8 Initial Start Up

Upon completion of all mechanical mounting and termination of all field wiring, apply system power in the range of 12-28VDC (24VDC typical) and observe the following normal conditions:

a) FP-624D display reads “0”, and no fault messages are flashing.

b) A temporary upscale reading may occur as the sensor heats up. This upscale reading will decrease to “0”

% within 1-2 minutes of power-up, assuming there is no gas in the area of the sensor.

Initial Operational Tests

After a warm up period of 1 hour, the sensor should be checked to verify sensitivity to combustible gas.

Material Requirements

-Detcon PN 600-610000-000 Splash Guard with integral Cal Port -OR-

-Detcon PN 943-000006-038 Threaded Calibration Adapter

- Detcon PN 942-520124-050 Span Gas; 50% LEL methane/balance Air at fixed flow rate of 200-500cc/min.

significant reading inaccuracies.

a) Attach the calibration adapter to the threaded sensor housing. Apply the test gas at a controlled flow rate

of 200 - 500cc/min (200cc/min is the recommended flow). Allow 1-2 minutes for the reading to stabilize. Observe that during the 1-2 minutes the display increases to a level near that of the applied calibration gas value.

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

Initial operational tests are complete. Detcon combustible 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 span calibration instructions in Section 3.4.

FP-624D InstructionManual Rev. 1.2 Page 12 of 42

ModelFP-624D

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.

3. Operation

3.1 Programming Magnet Operating Instructions

The Operator Interface of the FP-624D gas sensors is accomplished via two internal magnetic switches located above and below the LED display (Figure 14). The two switches, labeled “PGM1” and “PGM2”, allow for complete calibration and configuration, therebyeliminating the need for area de-classification or the use of hot permits.

Figure 13 Magnetic Programming Tool

The magnetic programming tool (Figure 13) is used to operate the magnetic switches. Switch action is defined as momentary contact, 3-second hold, and 10-second hold. (Hold times are defined as the time from the point

when the arrow prompt “▼” appears.) For momentary contact use, the programming magnet is briefly held

over a switch location. For 3-second hold, the programming magnet is held in place over the switch location for three seconds. For 10-second 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 14.

Program1

PGM 1

MODEL FP-624DHOUSTON,TEXAS

MicroSafe LEL Gas Sensor

ALM ALM

FLT 1 2 CAL

PGM 2

Program2

Figure 14 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. (Exception to this is with “Signal Output Check” mode.)

FP-624D Instruction Manual Rev. 1.2 Page 13 of 42

Model FP-624D

3.2 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 major items that include sub-menus as indicated below. (Refer to the complete Software Flow Chart.)

Normal Operation

Current Reading and Fault Status

Calibration Mode

AutoZero AutoSpan

Program Mode

View Sensor Status

Sensor Model Type Current Software Version Range of Detection AutoSpan Level Days Since Last AutoSpan Remaining Sensor Life Sensor Bridge Current Sensor Bridge Voltage Gas Factor Cal Factor mA Output Input Voltage Supply Sensor Temperature Serial ID Alarm 1 Level Alarm 1 Ascending Alarm 1 Latching Alarm 1 Energized Alarm 2 Level Alarm 2 Ascending Alarm 2 Latching Alarm 2 Energized Fault Latching

Fault Energized Set AutoSpan Level Set Gas Factor Set Cal Factor Set Bridge Voltage Signal Output Check Restore Default Settings Set Serial ID Alarm 1 Settings Alarm 2 Settings Fault Settings

FP-624D InstructionManual Rev. 1.2 Page 14 of 42

Software Flowchart

Model FP-624D

Normal Operation

PGM1 (3) PGM2 (3)

View Sensor Status

Auto Time-Out

PGM1/2 (M) PGM1/2 (3)

Model Type

Version X.XX

Range XXX ppm

AutoSpan @ XX

Last Cal XXDays

Sensor Life XXX%

Bridge Current

Bridge Voltage

Gas Factor

Cal Factor

mA Output XX.XX

Voltage XX.X VDC

Sensor Temp XXC

Serial ID

Alarm 1 Level

Alarm 1 Ascending

Alarm 1 Latching

Alarm 1 Energized

Alarm 2 Level

Alarm 2 Ascending

Alarm 2 Latching

Alarm 2 Energized

Fault Latching

Fault Energized

PGM1 (3) PGM2 (3)

inc

Calibration Mode

(Auto Zero)

Calibration Mode

(Auto Span)

Set AutoSpan Level

AutoTime-out

PGM1/2 (M) PGM1/2 (3)

PGM1 (S) PGM2 (S)

PGM1/2 (3)

Signal Output Check

Auto Time-Out

PGM2 (10)

Simulation

PGM1/2 (3)

Alarm 1 Settings

AutoTime-out

PGM1/2 (M) PGM1/2 (3)

Alarm 1 Level

PGM1 (S) PGM2 (S)

PGM1/2 (3)

Alarm 1 Ascending

Y/N

AutoTime-out

PGM1/2 (M) PGM1/2 (3)

Alarm 1Latching

Y/N

AutoTime-out

PGM1/2 (M) PGM1/2 (3)

Alarm 1 Energized

Y/N

AutoTime-out

PGM1/2 (M) PGM1/2 (3)

Set Gas Factor

Auto Time-Out

PGM1/2 (M)

PGM1/2 (3)

PGM1 (S)

inc

PGM2 (S)

PGM1/2 (3)

Restore Defaults

Auto Time-Out

PGM1/2 (M)PGM1/2 (M) PGM1/2 (10)

Defaults Restored

Alarm 2 Settings

AutoTime-out PGM1/2 (M)

PGM1/2 (3)

Alarm 2 Level

PGM1 (S) PGM2 (S)

PGM1/2 (3)

Alarm 2 Ascending

Y/N

AutoTime-out PGM1/2 (M)

PGM1/2 (3)

Alarm 2 Latching

Y/N

AutoTime-out PGM1/2 (M)

PGM1/2 (3)

Alarm 2 Energized

Y/N

AutoTime-out PGM1/2 (M)

PGM1/2 (3)

dec

Set Cal Factor

Auto Time-Out

PGM1/2 (M)

PGM1/2 (3)

PGM1 (S)

inc

PGM2 (S)

PGM1/2 (3)

Set Serial ID

Auto Time-Out

PGM1/2 (M)

PGM1/2 (3)

PGM1 (S)

inc

PGM2 (S)

PGM1/2 (3)

Fault Settings

AutoTime-out

Fault Latching

AutoTime-out

inc

Fault Energized

AutoTime-out

inc

PGM1/2 (M) PGM1/2 (3)

Y/N

PGM1/2 (M) PGM1/2 (3)

Y/N

PGM1/2 (M) PGM1/2 (3)

dec

Set Bridge Voltage

Auto Time-Out

PGM1/2 (M) PGM1/2 (3)

PGM1 (S)

inc

PGM2 (S)

PGM1/2 (3)

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

Figure 15 FP-624D Software Flowchart

FP-624D InstructionManual Rev. 1.2 Page 15 of 42

Model FP-624D

NOTE:

The zero gas source should have a normal background concentration of 20.9% O2.

NOTE:

Upon entering Calibration Mode, the 4

20mA signal drops to 2mA and is held at this

3.3 Normal Operation

In normal operation, the display continuously shows the current sensor reading, which will normally appear as “0”. Once every minute, the LED display will flash the sensor’s units of measure and the gas type (i.e. % LEL). If the sensor is actively experiencing any diagnostic faults, a “Fault Detected” message will scroll across the display once every minute instead of the units of measure and the gas type. At any time, while the sensor is in “Fault Detected” mode, PGM1 or PGM2 can be swiped to prompt the sensor to display a list of the active faults.

In normal operation, the 4-20mA current output linearly corresponds with the full-scale range.

3.4 Calibration Mode (AutoSpan)

Calibration Mode allows for sensor span calibration. Span calibration should be performed on a routine basis (quarterly minimum) to ensure reliable performance. If a sensor has been exposed to any de-sensitizing gases or to very high over-range combustible gas levels, then a re-calibration should be considered. Unless otherwise specified, span adjustment is recommended at 50% LEL. This function is called “AUTO SPAN.”

3.4.1 AutoZero

The AutoZero function is used to zero the sensor. Local ambient air can be used to zero calibrate the sensor as long as it can be confirmed that it contains no combustible gases. If this cannot be confirmed then a zero air cylinder should be used.

Material Requirements:

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

-Detcon PN 613-120000-000 Splash Guard with integral Cal Port -OR-

-Detcon PN 943-000006-132 Threaded Calibration Adapter

-Detcon PN 942-001123-000 Zero Air cal gas or use ambient air if no combustible gas is present.

Pure Nitrogen gas standards should not be used or errors may result.

a) If the ambient air is known to contain no combustible gas content, then it can be used to zero calibrate. If

a zero gas cal cylinder is going to be used then attach the calibration adapter and set flow rate of 200500cc/min and let sensor purge for 1-2 minutes before executing the AutoZero.

b) From Normal Operation, enter Calibration Mode by holding the programming magnet over PGM1 for 3-4

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

PGM1 for 3-4 seconds once the “▲” prompt appears to execute AutoZero (or allow to timeout in 10

seconds if AutoZero is not desired).

level until the program returns to normal operation. The “In Calibration” bit in the Modbus

Fault Status register will be set until the calibration is complete.

FP-624D InstructionManual Rev. 1.2 Page 16 of 42

ModelFP-624D

NOTE 1:

Before performing AutoSpan Calibration, verify that the AutoSpan level matches

NOTE 2:

The span gas source must have a normal background concentration of 20.9% O2.

NOTE 3:

If the target gas is other than methane, use the appropriate Gas Factor as described

NOTE 5:

To maintain the CSA certification, it must be calibrated on methane.

NOTE:

Upon entering Calibration Mode, the 4

20mA signal drops to 2mA and is held at this

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

sequence:

Zero Cal. . . Setting Zero . . . Zero Saved (each will scroll twice) d) Remove the zero gas and calibration adapter, if applicable.

3.4.2 AutoSpan

Material Requirements:

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

- Detcon PN 613-120000-000 Splash Guard with integral Cal Port -OR-

-Detcon PN 943-000006-132 Threaded Calibration Adapter

-Detcon PN 942-520124-050 50% LEL Methane in balance air (recommended) or other suitable span gas containing a certified level of % LEL concentration of combustible gas in air balance. A flow fixed rate of 200-500cc/min is recommended.

the span calibration gas concentration as described in Section 3.5.2 Set AutoSpan Level.

Pure Nitrogen background mixtures are not acceptable! Significant span calibration inaccuracies will result.

in Section 3.5.3 Set Gas Factor

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. This concentration must be equal to the calibration gas level setting. The factory default setting and recommendation for span gas concentration is 50% LEL. If a span gas containing the recommended concentration is not available, other concentrations may be used as long as they fall between 5% and 95% LEL. 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.

a) Verify that the AutoSpan Level is equal to the calibration span gas concentration. (Refer to View Sensor

Status in Section 3.5.1.) If the AutoSpan Level is not equal to the calibration span gas concentration, adjust the AutoSpan Level as instructed in Section 3.5.2 Set AutoSpan Level.

b) From Normal Operation, enter Calibration Mode by holding the programming magnet over PGM1 for 3-4

seconds. Note, the “▲” prompt will show that the magnetic switch is activated during the 3-4 second hold

period. The display will then scroll “PGM1=Zero…PGM2=Span”. Hold the programming magnet over PGM2 for 3-4 seconds once the “

▼” prompt appears, until the display starts to scroll “Span Cal” to

execute AutoSpan (or allow to timeout in 5 seconds if AutoSpan is not desired). The display will then scroll “Apply XX % LEL” (where XX is the AutoSpan Level).

level until the program returns to normal operation. The “In Calibration” bit in the Modbus

FP-624D Instruction Manual Rev. 1.2 Page 17 of 42

Model FP-624D

Fault Status register will be set until the calibration is complete.

NOTE 1

: If

the sensor fails the minimum signal change criteria, a

“Range Fault”

will be

NOTE 2

: If the sensor fails the stability criteria, a

“Stability Fault”

will be declared and a

NOTE 3

: If the sensor

fails the clearing time criteria, a “

Clearing Fault

” will be declared and a

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

rate). As the sensor signal begins to increase, the display will switch to reporting a flashing “XX” reading as the display shows the sensor’s “as found” response to the span gas presented. If it fails to meet the minimum in-range signal change criteria within 2½ minutes, the display will report “Range Fault” twice and the sensor will return to normal operation, aborting the AutoSpan sequence. The sensor continues to report a “Range Fault” and will not clear the fault until a successful AutoSpan is completed.

Assuming acceptable sensor signal change, after 1 minute the reading will auto-adjust to the programmed AutoSpan level. During the next 30 seconds, the AutoSpan sequence checks the sensor for acceptable reading stability. If the sensor fails the stability check, the reading is re-adjusted back to the AutoSpan level and the cycle repeats until the stability check is passed. Up to three additional 30-second stability check periods are allowed before the unit reports a “Stability Fault” twice and the sensor will return to normal operation, aborting the AutoSpan sequence. The sensor will continue to report a “Stability Fault” and will not clear the fault until a successful AutoSpan is completed.

If the sensor passes the stability check, the sensor display reports a series of messages: “AutoSpan Complete”

“Sensor Life XXX%”

“Remove Span Gas”

d) Remove the span gas and calibration adapter. The sensor will report a live reading as it clears toward “0”.

When the reading clears below 5 % LEL, the sensor will display “Span Complete” and will revert to normal operation. If the sensor fails to clear to less than 5% LEL within 5 minutes, a “Clearing Fault” will be reported twice and the sensor will return to normal operation, aborting the AutoSpan sequence. The sensor will continue to report a “Clearing Fault” and will not clear the fault until a successful AutoSpan is completed.

declared and a “Fault Detected” message will be displayed alternately with the sensor’s current reading. The 4-20mA output will be taken to 0mA and the “Range Fault” bit in the Modbus Fault Status register will be set.

“Fault Detected” message will be displayed alternately with the sensor’s current reading. The 4-20mA output will be taken to 0mA and the “Stability Fault” bit in the Modbus Fault Status register will be set.

“Fault Detected” message will be displayed alternately with the sensor’s current reading. The 4-20mA output will be taken to 0mA and the “Clearing Fault” bit in the Modbus Fault Status register will be set.

3.5 Program Mode

Program Mode provides a “View Sensor Status” menu to check operational and configuration parameters. Program Mode provides for adjustment of the AutoSpan Level, Bridge Voltage, Gas Factor, Cal Factor, Serial ID, Alarm and Fault Settings. Additionally, Program Mode includes the diagnostic functions “Signal Output Check” and “Restore Factory Defaults”.

FP-624D InstructionManual Rev. 1.2 Page 18 of 42

Model FP-624D

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

View Sensor Status Set AutoSpan Level Set Gas Factor Set Cal Factor Set Bridge Voltage Signal Output Check Restore Default Settings Set Serial ID Alarm 1 Settings Alarm 2 Settings Fault Settings

Navigating Program Mode

From Normal Operation, enter Program Mode by holding the magnet over PGM2 for 4 seconds (until the displays starts to scroll “View Sensor Status”). Note, the “

▼” prompt will show that the magnetic switch is

activated during the 4 second hold period. The sensor 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, immediately remove the magnet. The display 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 sensor will automatically revert to Normal Operation.

3.5.1 View Sensor Status

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

software version number, detection range, AutoSpan level, days since last AutoSpan, estimated remaining sensor life, bridge current, bridge voltage, gas factor, cal factor, mA output, input voltage, sensor ambient temperature, serial ID, alarm and fault settings.

From the 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:

Sensor Model Type

The menu item appears as: “FP-624D”

Current Software Version

The menu item appears as: “V X.XXZ6”

Range ofDetection

The menu item appears as: “Range XXX”

FP-624D InstructionManual Rev. 1.2 Page 19 of 42

AutoSpan Level

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

Days Since Last AutoSpan

The menu items appears as: “Last Cal XX days”

Remaining Sensor Life

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

Sensor BridgeCurrent

The menu item appears as: “Bridge XXXmA”

Sensor BridgeVoltage

The menu item appears as: “Bridge X.XXVDC

Gas Factor

The menu item appears as: “Gas Factor X.XX”

Cal Factor

The menu item appears as: “Cal Factor X.XX”

Model FP-624D

mA Output

The menu item appears as: “mA Output XX.XX mA”

Input VoltageSupply

The menu item appears as: “Voltage XX.X VDC”

Operating Temperature

The menu item appears as: “Temp XX C”

Serial ID

The menu item appears as: “Serial ID XX”

Alarm 1 Level

The menu item appears as: “Alarm 1 Level XX”

Alarm 1 Ascending

The menu item appears as: “Alarm 1 Ascending or Descending”

Alarm 1 Latching

The menu item appears as: “Alarm 1 Latching or Non-Latching”

Alarm 1 Energized

The menu item appears as: “Alarm 1 Energized or Non-Energized”

FP-624D InstructionManual Rev. 1.2 Page 20 of 42

Alarm 2 Level

The menu item appears as: “Alarm 2 Level XX”

Alarm 2 Ascending

The menu item appears as: “Alarm 2 Ascending or Descending”

Alarm 2 Latching

The menu item appears as: “Alarm 2 Latching or Non-Latching”

Alarm 2 Energized

The menu item appears as: “Alarm 2 Energized or Non-Energized”

Fault Latching

The menu item appears as: “Fault Latching or Non-Latching”

Fault Energized

The menu item appears as: “Fault Energized or Non-Energized”

Model FP-624D

When the status list sequence is complete, the display 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).

3.5.2 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 5% to 95% of selected full-scale range. The current setting can be viewed in View Program Status.

The menu item appears as: “Set AutoSpanLevel”.

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 span level). Swipe the magnet momentarily over PGM1 to increase or PGM2 to decrease the AutoSpan Level until the correct level is displayed. When the correct level is achieved, hold the magnet over PGM1 or 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).

3.5.3 Set Gas Factor

Because of the catalytic bead sensor’s almost universal response to combustible gases, the FP-624D sensor can be configured to specifically detect any of the combustible gases listed in Table 2. This gas is referred to as the “target gas”. In addition, the sensor can also be configured so that it can be calibrated with any of the listed gases regardless of which target gas is selected. This gas is referred to as the “cal gas”. These two features, Set Gas Factor and Set Cal Factor, allow a significant degree of flexibility in the detection and span calibration process.

FP-624D InstructionManual Rev. 1.2 Page 21 of 42

Model FP-624D

NOTE:

The default value for gas factor is 1.0. This would be used when methane is the target

gas. Values other than 1.0 would be used when the target gas is not methane.

Set Gas Factor is used to make the appropriate signal sensitivity adjustment when the target gas is a gas other than methane. This is necessary because the catalytic bead sensor has different signal strengths for each combustible gas and all reading calculations are made based on a reference to methane. The gas factor value is adjustable from 0.2 to 5.0. It represents the translation between the target gas and methane gas, where methane has a normalized gas factor = 1.0. For example, the gas factor for butane is 1.71, because the signal strength of butane is 1.71 times lower than methane. The current setting can be viewed in View Program Status – Gas Factor.

The following table shows the gas factors of most combustible gases that can be measured. Find the target gas and enter the corresponding value as the gas factor. For example, if butane were the target gas, the correct gas factor would be 1.71. If there is a mixture of target gases, use a weighted approach to determine the correct gas factor. For example, if the target gas was 50% butane and 50% methane, the correct gas factor would be calculated and entered as 0.5(1.71) + 0.5 (1.0) = 1.35.

Table 2 Gas/Cal Factors

Gas Factor Gas Factor Gas Factor

Acetaldehyde 1.66 Decane 3.05 Dimethyl Ether 1.60 Acetic Acid 1.84 Diethylamine 2.05 Methylethyl Ether 2.27 Acetic Anhydride 2.17 Dimethylamine 1.73 Methylethyl Ketone 2.42 Acetone 1.93 2,3-Dimethylpentane 2.51 Methyl Formate 1.49 Acetylene 1.76 2,2-Dimethylpropane 2.52 Methyl Mercaptan 1.64 Alkyl Alcohol 1.96 Dimethyl sulfide 2.30 Methyl propionate 1.95 Ammonia 0.79 1,4-Dioxane 2.24 Methyl n-propyl Ketone 2.46 n-Amyl Alcohol 3.06 Ethane 1.47 Naphtha 3.03 Aniline 2.54 Ethyl Acetate 1.95 Naphthalene 2.94 Benzene 2.45 Ethyl Alcohol 1.37 Nitromethane 1.72 Biphenyl 4.00 Ethylamine 1.90 n-Nonane 3.18 1,3-Butadiene 1.79 Ethyl Benzene 2.80 n-Octane 2.67 Butane 1.71 Ethylcyclopentane 2.52 n-Pentane 2.18 iso-Butane 1.93 Ethylene 1.41 iso-Pentane 2.15 Butene-1 2.20 Ethylene Oxide 1.93 Propane 1.81 cis-Butene-2 2.06 Diethyl Ether 2.16 n-Propyl Alcohol 2.12 trans-Butene-2 1.97 Ethyl Formate 2.26 n-Propylamine 2.07 n-Butyl Alcohol 2.91 Ethyl Mercaptan 1.78 Propylene 1.95 iso-Butyl Alcohol 1.89 n-Heptane 2.59 Propylene Oxide 2.18 tert-Butyl-Alcohol 1.34 n-Hexane 2.71 iso-Propyl Ether 2.29 n-Butyl Benzene 3.18 Hydrazine 2.22 Propyne 2.40 iso-Butyl Benzene 3.12 Hydrogen Cyanide 2.09 Toluene 2.47 n-Butyric Acid 2.63 Hydrogen 1.30 Triethylamine 2.51 Carbon Disulphide 5.65 Hydrogen Sulphide 2.54 Trimethylamine 2.06 Carbon Monoxide 1.32 Methane 1.00 Vinyl Chloride 2.32 Carbon Oxysulphide 1.07 Methyl Acetate 2.01 Vinyl Ethyl Ether 2.38 Cyanogen 1.12 Methyl Alcohol 1.16 o-Xylene 2.79 Cyclohexane 2.43 Methylamine 1.29 m-Xylene 2.55 Cyclopropane 1.60 Methylcyclohexane 2.26 p-Xylene 2.55

FP-624D InstructionManual Rev. 1.2 Page 22 of 42

Model FP-624D

NOTE:

The default value for cal factor is 1.0. This would be used when methane is the cal gas.

The menu item appears as: “Set Gas Factor”.

From the Set Gas Factor 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 Factor”). The display will then switch to “X.XX“(where X.XX is the current gas factor). Swipe the magnet momentarily over PGM1 to increase or PGM2 to decrease the gas factor level until the correct value is displayed. Hold the magnet over PGM1 or PGM2 for 3 seconds to accept the new value. The display will scroll “Factor Saved”, and revert to “Set Gas Factor” 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 Gas Factor” 4 times and then return to Normal Operation).

3.5.4 Set Cal Factor

Because of the catalytic bead sensor’s almost universal response to combustible gases, the FP-624D sensor can be span calibrated with any of the combustible gases listed in Table 2 above. This specific gas is referred to as the “cal gas”.

Values other than 1.0 would be used when the span cal gas is not methane.

Set Cal Factor is used to make the appropriate signal sensitivity adjustment when the cal gas is a gas other than methane. This is necessary because the catalytic bead sensor has different signal strengths for each combustible gas and all reading calculations are made based on a reference to methane. The cal factor value is adjustable from 0.2 to 5.0. It represents the translation between the cal gas and methane gas, where methane has a normalized cal factor = 1.0. For example, the cal factor for butane is 1.71 because the signal strength of butane is 1.71 times lower than methane. The current setting can be viewed in View Program Status.

Table 2 shows the cal factors of most combustible gases that will be used as span calibration sources. Find the gas of interest and enter that value the cal factor. For example, if propane were used as the cal gas, the correct cal factor would be 1.81.

The menu item appears as: “Set Cal Factor”.

From the Set Gas Factor 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 Factor”). The display will then switch to “X.XX“(where X.XX is the current cal factor). Swipe the magnet momentarily over PGM2 to decrease or PGM1 to increase the gas factor level until the correct value is displayed. Hold the magnet over PGM1 or PGM2 for 3-4 seconds to accept the new value. The display will scroll “Factor Saved”, and revert to “Set Cal Factor” 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 Cal Factor” 4 times and then return to Normal Operation).

3.5.5 Set Bridge Voltage

Each Detcon plug-in combustible gas sensor requires a one-time setting for optimal bridge voltage. This is set automatically during the “Set Bridge Voltage” sequence. The “Set Bridge Voltage” sequence determines the required bridge voltage such that every plug-in sensor operates at exactly 200mA current. This technique provides for tremendous uniformity in sensor-to-sensor operational performance, and it is notably better than

FP-624D InstructionManual Rev. 1.2 Page 23 of 42

Model FP-624D

NOTE:

The “Set Bridge Voltage” function is executed during factory calibration of every FP

NOTE

: Signal Output Check stays active indefinitely until the user stops the function. There

sensors that are operated on a common fixed bridge voltage platform. The range of bridge voltages required for Detcon sensors is generally between 2.5 – 2.9VDC.

624D sensor. In the field, this menu item is only needed when a replacement plug-in sensor is being installed, when mating a new FP-624D transmitter with an existing plug-in sensor or when remote mounting the sensor away from the transmitter.

The menu item appears as: “Set Bridge Voltage”.

From the Set Bridge Voltage text scroll, hold the magnet over PGM1 or PGM2 until the “▼” prompt appears and continue to hold the magnet in place for an additional 7-8 seconds (until the display starts to scroll “Setting Bridge”). The transmitter will then display “WAIT”. During the 1-minute sequence, the transmitter will display the three-digit number that corresponds to the bridge current as it is being adjusted. At conclusion, the display will scroll “Set Bridge Voltage”. The new bridge voltage can be viewed in the “View Sensor Status” menu.

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 Bridge Voltage” 4 times and then return to Normal Operation).

3.5.6 Signal Output Check

Signal Output Check provides a simulated 4-20mA and Modbus output. This simulation allows the user to

conveniently perform a functional system check of their entire safety system. This signal output simulation also aids the user in performing troubleshooting of signal wiring problems.

The menu item appears as: “Signal Output Check”.

From the “Signal Output Check” text scroll, hold the magnet over PGM1 or PGM2 until the “▼” prompt

appears and then hold continuously for an additional 10 seconds. Once initiated, the display will scroll “Simulation Active” until the function is stopped. During simulation mode, the 4-20mA value will be increased from 4.0mA to 20.0mA (in 1% of range increments at about a 1 second update rate) and then decreased from 20.0mA to 4.0mA. The value of the Modbus concentration register (40002) will also be increased and decreased in the same manner.

is no automatic timeout for this feature.

To end simulation mode, hold magnet over PGM1 or PGM2 for 3 seconds. The display will either move to the prior menu item or move to the next menu item respectively.

Move to another menu item by executing a momentary hold, or, return to Normal Operation via automatic timeout of about 15 seconds.

3.5.7 Restore Factory 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”.

FP-624D InstructionManual Rev. 1.2 Page 24 of 42

Model FP-624D

NOTE

: “Restoring Factory Defaults” should only be used when absolutely necessary. All

entered if this function is executed.

NOTE

: The user must remove and then reapply power to the sensor before the factory default

NOTE

: The following

must

be performed in order before the sensor can be placed back into

previously existing configuration inputs will have to be reA full 10-second magnet hold on PGM 1 is required to execute this function.

From the “Restore Defaults” text scroll, hold the programming magnet over PGM1 until the “▲” prompt

appears and continue to hold 10 seconds. The display will scroll “Restoring Defaults”, and then will revert to the “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 scroll “Restore Defaults” 4 times and then return to Normal Operation).

Following the execution of “Restore Defaults”, power to the FP-624D needs to be cycled before the FP-624D will revert to its factory default settings. The default settings are:

settings will be restored.

operation.

 AutoSpan Level = 50 %LEL. AutoSpan level must be set appropriately by the operator (Section 3.5.2).  Gas Factor = 1.0. The Gas Factor must be set appropriately by the operator (Section 3.5.3).  Cal Factor = 1.0. The Cal Factor must be set appropriately by the operator (Section 3.5.4).  AutoZero: AutoZero Settings are lost and user must perform new AutoZero (Section 3.4.1).  AutoSpan: AutoSpan Settings are lost and user must perform new AutoSpan (Section 3.4.2).  Serial ID: The Modbus address of the sensor must be set appropriately by the operator (3.5.8).  Alarm and Fault Settings: The alarm levels and relay properties must be set appropriately by the operator

(3.5.9 and 3.5.10)

3.5.8 Set Serial ID

Detcon Model FP-624D sensors can be polled serially via RS-485 Modbus™ RTU. Refer to Section 4.0 for details on using the Modbus™ output feature.

Set Serial ID is used to set the Modbus™ serial ID address. It is adjustable from 01 to 256 in hexadecimal format (01-FF hex). The current serial ID can be viewed in View Sensor Status using the instruction given in Section 3.5.1 View Sensor Status.

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

From the “Set Serial 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 decrease or PGM1 to increase the hexadecimal number until the desired ID is displayed. Hold the magnet over PGM1 or PGM2 for 3-4 seconds to accept the new value. The display will scroll “ID Saved”, and revert to “Set Serial 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).

FP-624D InstructionManual Rev. 1.2 Page 25 of 42

Model FP-624D

3.5.9 Alarm 1 and 2 Settings

The FP-624D contains two Form C alarm relay outputs. These relays can be configured to change state when the concentration exceeds a set level. The relays can be configured to operate in either energized or nonenergized mode. In non-energized mode, the normally open contact is open if the alarm level has not been reached. In energized mode, the normally open contact is closed if the alarm level has not been reached. Energized mode provides for fail-safe operation since a loss of power or cable failure will cause the contact to be open.

The alarm relays can be configured as either latching or non-latching. In non-latching mode, the relay is deactivated as soon as the sensor alarm condition is cleared. In latching mode, the relay remains active even after the alarm condition has cleared. Once activated, the relay can only be deactivated by swiping a magnetic programming tool above the PGM1 or PGM2 mark on the FP-624D face plate.

The menu item appears as: “Alarm X Settings”

From the “Alarm X Settings” 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 Level”). The display will then switch to “XXX“ (where XXX is the current alarm level in % LEL). Swipe the magnet momentarily over PGM2 to decrease or PGM1 to increase the alarm level until the desired level is displayed. Hold the magnet over PGM1 or PGM2 for 3 seconds to accept the new value (until the display starts to scroll “Level Saved”).

The display will scroll “Set Ascending”, and then switch to “Yes” or “No”. “Yes” indicates the relay is in ascending mode and “No” indicates the relay is in descending mode. Swipe the magnet momentarily over PGM2 or PGM1 until the correct value is displayed. Hold the magnet over PGM2 for three seconds to save the setting.

The display will scroll “Set Latching”, and then switch to “Yes” or “No”. “No” indicates the relay is nonlatching and “Yes” indicates the relay is latching. Swipe the magnet momentarily over PGM2 or PGM1 until the correct value is displayed. Hold the magnet over PGM2 for three seconds to save the setting.

The display will scroll “Set Energized”, and then switch to “Yes” or “No”. “No” indicates the relay is normally non-energized and “Yes” indicates the relay is normally energized. Swipe the magnet momentarily over PGM2 or PGM1 until the correct value is displayed. Hold the magnet over PGM2 for three seconds to save the setting.

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 “Alarm X Settings” 4 times and then return to Normal Operation).

3.5.10 Fault Settings

The FP-624D contains a single Form C fault relay output. This relay can be configured to change state when the sensor experiences a fault condition. This relay can be configured to operate in either energized or nonenergized mode. In non-energized mode, the normally open contact is open if the sensor is not in fault. In energized mode, the normally open contact is closed if the sensor is not in fault. Energized mode provides for fail-safe operation since a loss of power or cable failure will cause the contact to be open.

FP-624D InstructionManual Rev. 1.2 Page 26 of 42

Model FP-624D

The fault relay can be configured as either latching or non-latching. In non-latching mode, the relay is deactivated as soon as the fault condition is cleared. In latching mode, the relay remains active even after the fault condition has cleared. Once activated, the relay can only be deactivated by swiping a magnetic programming tool above the PGM1 or PGM2 mark on the FP-624D face plate.

The menu item appears as: “Fault Settings”

From the “Fault Settings” 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. The display will scroll “Set Latching”, and then switch to “Yes” or “No”. “No” indicates the relay is non-latching and “Yes” indicates the relay is latching. Swipe the magnet momentarily over PGM2 or PGM1 until the correct value is displayed. Hold the magnet over PGM2 for three seconds to save the setting.

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 “Fault Settings” 4 times and then return to Normal Operation).

3.6 Program Features

Detcon FP-624D combustible gas sensors incorporate a comprehensive set of diagnostic features to achieve Fail-Safe Operation. These Operational features and Failsafe Diagnostic features are detailed below.

3.6.1 Operational Features

Over-Range

When gas greater than the full-scale range is detected, the sensor display will continuously flash the full-scale reading of 100. This designates an over-range condition. The 4-20mA signal will report a 22mA output during this time. The Modbus concentration register will report the measured concentration (up to full scale + 10%).

In-Calibration Status

When the sensor is engaged in AutoZero or AutoSpan calibration, the 4-20mA output signal is taken to

2.0mA. This alerts the user that the sensor is not in an active measurement mode. This feature also allows the user to log the AutoZero and AutoSpan events via their master control system. The “In Calibration” bit in the Modbus fault register is set while the sensor is in calibration mode.

Sensor Life

Sensor Life is calculated after each AutoSpan calibration and is reported as an indicator of remaining service life. It is reported in the “View Sensor Status” menu and a Modbus register. Sensor Life is reported on a scale of 0-100%. When Sensor Life falls below 25%, the sensor cell should be replaced within a reasonable maintenance schedule.

Last AutoSpanDate

This reports the number of days that have elapsed since the last successful AutoSpan. This is reported in the View Sensor Status menu. After 180 days, an AutoSpan Fault will be declared.

FP-624D InstructionManual Rev. 1.2 Page 27 of 42

Model FP-624D

NOTE

: Refer to the Troubleshooting Guide, Section

, for guidance on fault conditions.

3.6.2 Fault Diagnostic/Failsafe Features

Fail-Safe/Fault Supervision

Model FP-624D MicroSafe™ sensors are designed for Fail-Safe operation. If any of the diagnostic faults listed below are active, the sensor display will scroll the message “Fault Detected” every 60 seconds during normal operation. At any time during “Fault Detected” mode, holding the programming magnet over PGM1 or PGM2 for 1 second will display the active fault(s). All active faults are reported sequentially.

Most fault conditions result in failed operation of the sensor. In these cases the 4-20mA signal is dropped to the universal fault level of 0mA. The “Global Fault” bit in the Modbus fault register is also set and the fault relay output is activated. These include the AutoZero and AutoSpan Calibration faults, Sensor Faults, Processor Fault, Memory Fault, Loop Fault, and Input Voltage Fault. (The 0mA fault level is not employed for a Temperature Fault, or during Calibration.)

Zero Fault

If the sensor drifts below –10% LEL, the “Zero Fault” will be declared. A “Zero Fault” will cause a “Fault Detected” message to scroll once a minute on the transmitter display and drop the 4-20mA output to 0mA. The “Zero Fault” bit in the Modbus fault register will be set. The sensor should be considered “Out-ofService” until a successful AutoZero calibration is performed.

Range Fault – AutoSpan

If the sensor fails the minimum signal change criteria during AutoSpan sequence (Section 3.4), the “Range Fault” will be declared. A “Range Fault” will cause a “Fault Detected” message to scroll once a minute on the sensor display and drop the 4-20mA output to 0mA. The “Range Fault” bit in the Modbus fault register will be set. The sensor should be considered “Out-of-Service” until a successful AutoSpan calibration is performed.

Stability Fault - AutoSpan

If the sensor fails the signal stability criteria during AutoSpan sequence (Section 3.4), the “Stability Fault” will be declared. A “Stability Fault” will cause a “Fault Detected” message to scroll once a minute on the sensor display and drop the mA output to 0mA. The “Stability Fault” bit in the Modbus fault register will be set. The sensor should be considered as “Out-of-Service” until a successful AutoSpan calibration is performed.

Clearing Fault - AutoSpan

If the sensor fails the signal stabilitycriteria during AutoSpan sequence (Section 3.4), the “Clearing Fault” will be declared. A “Clearing Fault” will cause a “Fault Detected” message to scroll once a minute on the sensor display and drop the mA output to 0mA. The “Clearing Fault” bit in the Modbus fault register will be set. The sensor should be considered as “Out-of-Service” until a successful AutoSpan calibration is performed.

Sensor Current Fault

If the current through the sensor bridge (See Figure 3) drifts outside the range of 200mA ± 50mA, a “Sensor Current Fault” will be declared. A “Sensor Current Fault” will cause a “Fault Detected” message to scroll once a minute on the transmitter display. If a Sensor Current Fault occurs, the 4-20mA signal will be set at 0mA and the “Sensor Current Fault” bit will be set until the fault condition is resolved.

Sensor VoltageFault

FP-624D InstructionManual Rev. 1.2 Page 28 of 42

Model FP-624D

If the voltage across the sensor bridge (See Figure 3) is greater than 3.5VDC or less than 1.8VDC, a “Sensor Voltage Fault” will be declared. A “Sensor Voltage Fault” will cause a “Fault Detected” message to scroll once a minute on the transmitter display. If a Sensor Voltage Fault occurs, the 4-20mA signal will be set at 0mA and the “Sensor Voltage Fault” bit will be set until the fault condition is resolved.

Processor Fault

If the detector has any unrecoverable run-time errors, a “Processor Fault” is declared. A “Processor Fault” will cause a “Fault Detected” message to scroll once a minute on the sensor display. If a Processor Fault occurs, the 4-20mA signal will be set at 0mA and the “Processor Fault” bit will be set until the fault condition is resolved.

Memory Fault

If the detector has a failure in saving new data to memory, a “Memory Fault” is declared. A “Memory Fault” will cause the “Fault Detected” message to scroll once a minute on the sensor display. If a Memory Fault occurs, the 4-20mA signal will be set at 0mA and the “Memory Fault” bit will be set until the fault condition is resolved.

4-20mA Loop Fault

If the detector measures a 4-20mA loop load resistance > 1000 ohms, a “4-20mA Fault” is declared. A “420mA Fault” will cause the “Fault Detected” message to scroll once a minute on the sensor display. If a Loop Fault occurs, the 4-20mA signal will be set at 0mA and the “4-20mA Fault” bit will be set until the fault condition is resolved.

Input VoltageFault

If the detector is currently receiving an input voltage that is outside of the 11.5-28VDC range, an “Input Voltage Fault” is declared. An “Input Voltage Fault” will cause the “Fault Detected” message to scroll once a minute on the sensor display. If an Input Voltage Fault occurs, the 4-20mA signal will be set at 0mA and the “Input Voltage Fault” bit will be set until the fault condition is resolved.

Temperature Fault

If the detector is reporting currently an ambient temperature that is outside of the –40ºC to +75ºC range, a “Temperature Fault” is declared. A “Temperature Fault” will cause the “Fault Detected” message to scroll once a minute on the sensor display. If a Temperature Fault occurs, the 4-20mA signal remains operational, but the ‘Temperature Fault” bit will be set.

AutoSpan Fault

If 180 days has elapsed since the last successful AutoSpan, an AutoSpan Fault will be generated. An “AutoSpan Fault” will cause the “Fault Detected” message to scroll once a minute on the sensor display. If an AutoSpan Reminder Fault, the 4-20mA signal remains operational, but the “Auto Span Fault” bit will be set.

FP-624D InstructionManual Rev. 1.2 Page 29 of 42

Model FP-624D

40000

Device Type

R8700 Sensor

40001

ReadDetectable Range

1,2

R/W

100

For 0-100DM–

0 to 10000

40003

ReadAutoSpanLevel

4,2

R/W50Span gas at 50

DM–1% to 95% of Range

40003

Write

AutoSpan Level

FP–5% to 95% of Range (40001)

IR–5% to 95%of Range (40001)

PI–1% to 95%of Range (40001)

40005

Read Fault Status Bits

0x0001

Global Fault

0x0004

Temperature Fault

0x0040

Processor Fault

0x0800

Zero Fault

0x4000

In Calibration

Function Dependant on Value

Value

Meaning

Range

03/

40012

Special #2

R/W

Function Dependanton Value

of 40006 (See Special Register

Table)

4. RS-485 Modbus

Model FP-624D sensors feature Modbus™ compatible communications protocol output and are addressable via the program mode. Communication is via a two wire, half duplex RS-485, 9600 baud, 8 data bits, 1 stop bit, no parity, with the sensor set up as a slave device. A master controller up to 4000 feet away can poll up to 256 different FP-624D sensors. This number may not be realistic in harsh environments where noise and/or wiring conditions would make it impractical to place so many devices on the same pair of wires. If a multipoint system is being utilized, each sensor should be set for a different address. Typical address settings are: 01, 02, 03, 04, 05, 06, 07, 08, 09, 0A, 0B, 0C, 0D, 0E, 0F, 10, 11…etc.

Sensor Serial ID numbers are factory default to 01. These can be changed in the field via the Operator Interface described in Section 3.5.8.

The following table explains the details of the Modbus™ protocol that the FP-624D sensor supports.

Modbus Registers

FC REG Content Description R/W Content Definition

Value Meaning Range

Protocol

Table 3 Modbus Registers

06 40001 Write Detectable Range 10000 For 0-10000

03 40002

03 40004 Read Sensor Life R 85 For 85% sensor life

03 40006 Read Model # R 1, 2, 3, 4, 5

03 40007 Read Days SinceCal R 29 29days 03 40008 03 40009 03 40010 Read Temperature R 28 28 °C

03/

40011 Special #1 R/W

FC REG Content Description R/W Content Definition

ReadConcentration

4-20 Current Output

Read Input Voltage

3,2

R 1000 Bound by range. If > range, this

0x0002 Auto Span Fault

0x0008 4-20mA Fault 0x0010 Input Voltage Fault 0x0020 Memory Fault

0x0080 Clearing Fault 0x0100 Stability Fault 0x0200 Range Fault 0x0400 Sensor Fault

0x1000 SensorFault 2 0x2000 <reserved>

0x8000 Communication Error

R 400 4.00mA R 2400 24.00V

value is in fault.

DM, FP, IR, TP, PID respectively

FP – Read only TP – 20,50, 100, 200 IR – 0 to 10000 PI – 0 to 10000

TP – 2% to 50% of Range (40001)

FP-624D InstructionManual Rev. 1.2 Page 30 of 42

03 40013 Special #3 R

Function

Dependant on Value

03/

40014

Special #4

R/W

Function Dependanton Value

of 40006 (See Special Register

40015

Calibration Status

0x0000

Idle

0x0002

Span Calibration Started

0x0003

Span Set

0x0004

Span Calibration Unsuccessful

40015

Calibration Enable

0x0001

Set Zero

0x0009

Set FP Bridge Voltage

40017

Read Text 2

Two Char of Gas/UnitsString

40018

Read Text 3

Two Char of Gas/UnitsString

40019

Read Text 4

Two Char of Gas/UnitsString

40020

Read Text 5, last char in H

Two Char of Gas/UnitsString

40021

Text null terminator in L

Two Char of Gas/UnitsString

40023

Processor Firmware Version

0x0102

Version 01.02

Character #

1234567891011

Description

Units

0x20

Gas Type

0x0

of 40006 (See Special Register

Table)

0x0001 Zero Calibration Started

0x0002 Set Span 0x0008 Signal simulation mode

0x000A Set TP Heater Power 0x000B Set IR Gain

03 40016 Read Text 1, first char in L R Two Char of Gas/Units String

Model FP-624D

03 40022 Special #5 R/W

Units are determined by “units”field in the “notation”string

Span Gas must be between5% and 95% of the detectable range and is usually about 50% of it.

Fault status bits self-reset when fault clears

Text in ASCII, in order L byte, H byte, L byte… Seefield descriptions of notation string.

Function Dependanton Value

of 40006 (See Special Register

Table)

Table 4 Notation Text String Description

Units – This field is typically ‘_ % _’ (where ‘_ ‘ is a space, 0x20). 0x20 – The units fieldis terminated with an ASCII space (0x20)

Gas Type – This field contains the gas type of the cell (typically “LEL _ _ _”) 0x00 – The notation string is terminated with an ASCII null character

FP-624D InstructionManual Rev. 1.2 Page 31 of 42

Model FP-624D

NOTE

: It is necessary to remove power while changing the combustible gas sensor in order

NOTE

: It is necessary to remove power to the junction box

while changing the Transmitter

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. If, after 180 days, an AutoSpan calibration is not performed, the sensor will generate an AutoSpan fault.

Visual Inspection

The sensor should be inspected annually. Inspect for signs of corrosion, pitting, and water damage. During visual inspection, the splash guard should be inspected to insure that it is not blocked. Examine the porous 316SS flame arrestor within the sensor’s bottom housing for signs of physical blockage or severe corrosion. Also, inspect inside the junction box for signs of water accumulation or terminal block corrosion.

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.

Replacement of Combustible Gas Sensor

maintain area classification while the junction box cover is removed. Proper “Hot Permits” may apply.

a) Remove the junction box cover and remove the Transmitter Module from the connector PCB. b) Unthread the lower half of the sensor housing. The lower housing includes two recessed holes for a

spanner wrench if needed. c) Gently pull on the combustible gas cell to unplug it from the upper housing. d) Orient the new plug-in sensor so that it matches with the female connector pins, and insert into the

upper housing. e) Thread the lower housing back into the upper housing and tighten using a spanner wrench. f) Perform “Set Bridge Voltage” (Section 3.5.5) to match the new combustible gas sensor with the

Transmitter Module. g) Perform a successful AutoZero and AutoSpan to match the new combustible gas sensor with the

Transmitter Module (Section 3.4).

Replacement of Transmitter Module

a) Remove the junction box cover and remove the Transmitter Module from the Connector PCB.

Module in order to maintain area classification.

b) Plug the new Transmitter Module into the connector PCB, and reinstall the junction box cover.

c) Perform Set Range, Set Heater Power, and Set AutoSpan Level then perform a successful AutoSpan before placing sensor assembly into operation.

FP-624D InstructionManual Rev. 1.2 Page 32 of 42

Model FP-624D

NOTE

: It is necessary to remove power to the junction box while changing the connector PCB

Replacement of the Connector PCB

in order to maintain area classification.

a) Remove the junction box cover and remove the transmitter module from the connector PCB.

b) Remove the black, white, blue, and yellow wires coming from the combustible gas sensor from the

connector PCB.

c) Remove the output wiring from the connector PCB terminals.

d) Remove the two 6-32 screws holding the connector PCB to the base of the junction box, and remove the

connector PCB.

e) Install the new connector PCB using the two 6-32 screws removed in step d).

f) Re-connect the output wiring to the terminals on the connector PCB.

g) Reconnect the black, white, blue, and yellow wires from the combustible gas sensor to the connector PCB.

h) Reinstall the transmitter module, and the junction box cover.

FP-624D InstructionManual Rev. 1.2 Page 33 of 42

ModelFP-624D

6. Troubleshooting Guide

Refer to the list of Failsafe Diagnostic features listed in Section 3.6.2 for additional reference in troubleshooting activities. Listed below are some typical trouble conditions and their probable cause and resolution path.

Figure 16 Replaceable Combustible Gas Sensor

Sensor Current/Voltage Fault

Probable Cause: Plug-in sensor has failed Remove plug-in sensor and verify resistance between PIN 5 and PIN 7 and PIN 2 and PIN 4 using an ohmmeter. At room temperature, the normal reading range should be 2.5-3.5 ohms for both catalytic beads. Replace plug-in sensor if either measurement is open circuit or significantly out-of range.

Figure 17 Plug-in Sensor (Bottom View)

Zero Fault

Probable Causes: Plug-in sensor has drifted Perform AutoZero calibration per Section 3.4.1 Replace the plug-in sensor.

AutoSpan Calibration Faults – (Range, Stability, and Clearing)

To clear anyAutoSpan Calibration fault, the AutoSpan process must be completed successfully (Section 3.4).

Range Fault

Probable Causes: Failed sensor, cal gas not applied or not applied at appropriate time, or problems with cal gas and delivery Check bridge voltage (should be 2.7 +/- 0.2VDC).

FP-624D Instruction Manual Rev. 1.2 Page 34 of 42

Model FP-624D

Check validity of span gas and flow rate (check MFG date on cal cylinder).

Make sure correct cal factor is set

Check for obstructions through stainless steel sinter element (including being wet).

Replace the plug-in sensor.

Stability Fault

Probable Causes: Failed sensor, emptyor close to empty cal gas cylinder, or problems w/ cal gas and delivery

Check bridge voltage (should be 2.7 +/- 0.2VDC).

Check validity of span gas and flow rate (check MFG date on cal cylinder).

Make sure correct cal factor is set

Check for obstructions through stainless steel sinter element (including being wet).

Replace the plug-in sensor.

Clearing Fault

Probable Causes: Failed sensor, cal gas not removed at appropriate time, problems with cal gas and delivery,

or background combustible gases preventing clearing

Confirm that no combustible gasses are present in background.

Check bridge voltage (should be 2.7 +/- 0.2VDC).

Check validity of span gas and flow rate (check MFG date on cal cylinder).

Make sure correct cal factor and gas factor is set

Check for obstructions through stainless steel sinter element (including being wet).

Replace the plug-in sensor.

Poor CalibrationRepeatability

Probable Causes: Failed sensor, use of wrong cal gas, problems with cal gas and delivery, or poison or

inhibitor gases

Check for adequate sensor life.

Check bridge voltage (should be 2.7 +/- 0.2VDC).

Check validity of span gas and flow rate (check MFG date on cal cylinder).

Check for obstructions through stainless steel sinter element (including being wet).

Evaluate area for presence of poisoning or inhibiting gases as listed in Section 2.3.

Increase calibration frequency.

Note the sensor’s serial # and report repetitive problems to Detcon’s Repair Department.

Replace plug-in 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 blocks.

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 erroneous readings.

Determine if cause is RFI induced.

FP-624D InstructionManual Rev. 1.2 Page 35 of 42

Model FP-624D

Processor and/or Memory Faults

Recycle power in attempt to clear problem Restore factory defaults - This will clear the processor’s memory and may correct problem. Remember to reenter all customersettings for range and cal gas level after Restore Factory Defaults. If problem persists, replace the plug-in transmitter module.

Unreadable Display

If due to excessive sunlight, install a sunshade to reduce glare.

Nothing Displayed – Transmitter not responding

Verify condulet has no accumulated water or abnormal corrosion. Verify required DC power is applied to correct terminals. Swap with a known-good transmitter module to determine if transmitter module is faulty.

Faulty 4-20mAOutput

If sensor has a normal reading with no faults displayed, and the 4-20 mA signal output is 0mA…. Check that wiring is properly connected at terminal blocks and through to controller inputs. The 4-20mA output loop must be closed (resistance of < 1000 ohms) to avoid the Loop Fault. Perform a “Signal Output Check” sequence via Section 3.5.6 and verify 4-20mA output with current meter. Swap with a known-good transmitter module to determine if the transmitter module’s 4-20mA output circuit is faulty.

FP-624D InstructionManual Rev. 1.2 Page 36 of 42

Model FP-624D

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 FP-624D combustible gas sensor to be free from defects in workmanship of

material under normal use and service for two years from the date of shipment on the transmitter electronics

and for a two year conditional period on the combustible gas cell. See Warranty details in Section 8 FP-624D

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 byDetcon 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.

FP-624D InstructionManual Rev. 1.2 Page 37 of 42

Model FP-624D

8. FP-624D Sensor Warranty

Plug-in Combustible Gas Sensor Warranty

Detcon Inc. warrants, under normal intended use, each new plug-in combustible gas sensor (PN 370-201600000 (Uses p/n 365-037020-160 in shipping container)). The warranty period begins on the date of shipment to the original purchaser and ends 2 years thereafter. The sensor element is warranted 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 Blvd, Suite 100, The Woodlands, Texas 77381, for necessary repairs or replacement.

Terms & Conditions * The original serial number must be legible on each sensor element. * 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.

Transmitter Module Warranty

Detcon Inc. warrants, under intended normal use, each new transmitter module to be free from defects in material and workmanship for a period of two years 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 transmitter. * 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 transmitter replacement.

FP-624D InstructionManual Rev. 1.2 Page 38 of 42

Model FP-624D

9. Appendix

9.1 Specifications

Sensor Type: Continuous diffusion/adsorption type

Matched-Pair Catalytic Bead type True plug-in replaceable type

Sensor Life: 3-5 years typical

Measuring Ranges: 0-100% LEL

Accuracy/ Repeatability: ± 3% LEL in 0-50% LEL range, ± 5% LEL in 51-100% LEL range

Response Time: T50 < 10 seconds, T90 < 30 seconds

Performance Testing: Complies with CSA C22.2 No. 152-M1984, ANSI/ISA S12.13

Electrical Classification: CSA and US (NRTL)

Class I, Division 1, Groups B, C, D

Approvals:

Applicable Standards CSA C22.2 No. 30-M1986

Warranty: Electronics – 2 years

Environmental Specifications

Operating Temperature: -40°C to +75°C

Storage Temperature: -40°C to +75°C

Operating Humidity: 0-100% RH (Non-condensing)

Operating Pressure: Ambient ± 10%

Electrical Specifications

CSAUS(To maintain the CSA certification, it must be calibrated on methane)

CSA C22.2 No. 142-M1987 CSA C22.2 No. 152-M1984 UL Std. No. 916 UL Std. No.1203 ANSI/ISA S12.13

Sensor – 2 years

Input Voltage: 12-28 VDC

Power Consumption: Normal operation = 68mA (<1.7 watt); Maximum = 87mA (2 watts)

RFI/EMI Protection: RFI Complies with ISA 92.0.01

Analog Output: Linear 4-20mA DC current

FP-624D InstructionManual Rev. 1.2 Page 39 of 42

1000 ohms maximum loop load @ 24VDC 0mA All Fault Diagnostics 2mA In-Calibration 4-20mA 0-100% full-scale 22mA Over-range condition

Serial Output: RS-485 Modbus™ RTU

Baud Rate 9600 BPS (9600, N, 8, 1 Half Duplex)

Relay Outputs: Alarm 1, Alarm 2, and Fault

5A @ 250VAC 5A @ 30VDC

Status Indicators: 4-digit LED Display with gas concentration, full-script menu

Prompts for AutoSpan, AutoZero, Set-up Options, and Fault Reporting

Faults Monitored: Loop Fault, Input Voltage Fault, Zero Fault, Sensor Fault,

Processor Fault, Memory Fault, Calibration Fault(s) 4 LEDs for Alarm 1, Alarm 2, Fault, and Calibration

Cable Requirements: Power/Analog: 3-wire shielded cable

Maximum distance is 13,300 feet with 14 AWG

Model FP-624D

Serial Output: 2-wire twisted-pair shielded cable specified for RS-485 use Maximum distance is 4,000 feet to last sensor

Mechanical Specifications

Length: 8 inches (200mm), including Splashguard

Width: 5.5 inches (140mm)

Weight: 2.7lbs (3.4Kg)

Mechanical Connection: ¾” Male NPT threaded connection

Electrical Connection: Eleven 14 gauge (maximum) wire terminal landings

FP-624D InstructionManual Rev. 1.2 Page 40 of 42

9.2 Spare Parts, Sensor Accessories, Calibration Equipment

926-5255

D0-100FP-

624D Plug

in Transmitter

Module

370-201600

000

Replacement Plug

in Sensor

600-02056

-0FP-P Plug

in Hsg Thr

eaded

Insert 316SS

612-820000

000

Replacement LEL sensor housing (includes threaded insert)

500-001794

004

Standard

Connector PCB

960-202200

000

Condensation prevention packet (for J

Box replace annually)

897-850800

010

NEMA 7 Aluminum Enclosure less cover

–

3 port

897-850400

010

NEMA 7 Aluminum Enclosure Cover (Blank)

897-850801

316

NEMA 7 316SS

Enclosure less cover

–

3 port

897-850401

316

NEMA 7 316SS Enclosure Cover (Blank)

613-120000

000

Sensor Splashguard with integral Cal

Port

943-002273

000

Harsh Location Dust guard

327-000000

000

Programming Magnet

960-202200

000

Condensation

prevention packet (for J

Box replace annually)

943-000006

132

Threaded Calibration Adapter

943-020000

000

Span Gas Kit: Includes calibration adapter, In

Line Humidifying Tube,

942-520124

050

Span Gas cylinder: 50% LEL Methane balance air

943-090005

502

200cc/min Fixed Flow Regulator for span gas bottle

926-5255

D0-100FP-

624D Plug

in Transmitter Module

370-201600

000

Replacement Plug

in Sensor

600-02056

-0FP-P Plug

in Hsg Thr

eaded

Insert 316SS

612-820000

000

Replacement LEL sensor housing (includes threaded insert)

500-001794

004

Standard Connector PCB

960-202200

000

Condensation prevention packet (for

J-Box replace annually)

Part Number Spare Parts

(Uses p/n 365-037020-160 in shipping container)

Sensor Accessories

Model FP-624D

Calibration Accessories

200cc/min fixed flow regulator, and carrying case. (Does Not include gas).

Contains 104 liters of gas and is good for 175 calibrations

Recommend Spare Parts for 2 Years

(Uses p/n 365-037020-160 in shipping container)

FP-624D InstructionManual Rev. 1.2 Page 41 of 42

9.3 Revision Log

Revision

Date

Changes made

Approval

0.0

8/9/2010

Initial Release

LBU

0.1

10/6/10

Updated software flowchart, revised operational guidelines for

1.0

12/02/10

Made

previous section 2.7 into 2.8 and inserted new section 2.7.

1.1

06/21/11

Changed spare part 365

037020

160 to 370

201600

000 and

safe use, references to 3 relay outputs

Added CSA note in section 3.4.2 and section 9.1. Revised note in section 3.5.5.

referenced that it is same part in shipping container

1.2 04/23/12 Updated section 2.6 Field Wiring, load resistor. Corrected spare parts LU

Model FP-624D

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

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

FP-624D InstructionManual Rev. 1.2 Page 42 of 42

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

Detcon FP-624D User Manual

Specifications and Main Features

Frequently Asked Questions

User Manual