Detcon FP-524D User manual

INSTRUCTION MANUAL
Detcon Model FP-524D
PGM 1
PGM 2
MODEL FP-524DHOUSTON, TEXAS
FLT 1 2 CAL
MicroSafe LEL Gas Sensor
ALM ALM
TM
FP-524D Combustible Gas Sensor
(0 – 100% LEL)
DETCON, Inc.
4055 Technology Forest Blvd, Suite 100,
The Woodlands, Texas 77381
Ph.281.367.4100 / Fax [phone]
www.detcon.com
June 06, 2018 • Document #3597 • Revision 1.6

Model FP-524D
FP-524D Instruction Manual ii
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Model FP-524D
FP-524D Instruction Manual iii
Table of Contents
1. Introduction ..................................................................................................................................................1
1.1 Description.......................................................................................................................................... 1
1.2 Modular Mechanical Design............................................................................................................... 3
2. Installation....................................................................................................................................................5
2.1 Operational Guidelines for Safe Use .................................................................................................. 5
2.2 Sensor Placement................................................................................................................................ 5
2.3 Sensor Contaminants and Interference ............................................................................................... 6
2.4 Mounting Installation.......................................................................................................................... 7
2.5 Electrical Installation.......................................................................................................................... 7
2.6 Field Wiring........................................................................................................................................ 9
2.7 Remote Mounting Installation .......................................................................................................... 10
2.7.1 Bridge Voltage Adjustment.......................................................................................................... 11
2.8 Initial Start Up................................................................................................................................... 11
3. Operation....................................................................................................................................................12
3.1 Programming Magnet Operating Instructions................................................................................... 12
3.2 Operator Interface............................................................................................................................. 13
3.3 Normal Operation ............................................................................................................................. 15
3.4 Calibration Mode (AutoZero and AutoSpan) ................................................................................... 15
3.4.1 AutoZero....................................................................................................................................... 15
3.4.2 AutoSpan...................................................................................................................................... 16
3.5 Program Mode .................................................................................................................................. 17
3.5.1 View Sensor Status....................................................................................................................... 18
3.5.2 Set AutoSpan Level...................................................................................................................... 20
3.5.3 Set Gas Factor............................................................................................................................... 20
3.5.4 Set Cal Factor ............................................................................................................................... 21
3.5.5 Set Bridge Voltage........................................................................................................................ 22
3.5.6 Signal Output Check..................................................................................................................... 23
3.5.7 Restore Factory Defaults .............................................................................................................. 23
3.5.8 Alarm 1 and 2 Settings ................................................................................................................. 24
3.5.9 Fault Settings................................................................................................................................ 24
3.6 Program Features .............................................................................................................................. 25
3.6.1 Operational Features..................................................................................................................... 25
3.6.2 Fault Diagnostic/Failsafe Features ............................................................................................... 25
4. Service and Maintenance............................................................................................................................28
5. Troubleshooting Guide...............................................................................................................................30
6. Customer Support and Service Policy........................................................................................................33
7. FP-524D Sensor Warranty..........................................................................................................................34
8. Appendix ....................................................................................................................................................35
8.1 Specifications.................................................................................................................................... 35
8.2 Spare Parts, Sensor Accessories, Calibration Equipment................................................................. 37
8.3 Revision Log..................................................................................................................................... 38

Model FP-524D
FP-524D Instruction Manual iv
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.................................................................................................................................... 2
Figure 5 Circuit Functional Block Diagram......................................................................................................... 3
Figure 6 FP-524D Transmitter Module................................................................................................................ 3
Figure 7 LEL Sensor Housing with replaceable Sensor....................................................................................... 4
Figure 8 Base Connector Board ........................................................................................................................... 4
Figure 9 Typical Outline and Mounting Dimensions........................................................................................... 7
Figure 10 Typical Installation .............................................................................................................................. 8
Figure 11 Sensor Connector PCB......................................................................................................................... 9
Figure 12 Remote Sensor Wiring Diagram....................................................................................................... 10
Figure 13 Magnetic Programming Tool............................................................................................................. 12
Figure 14 Magnetic Programming Switches.................................................................................................... 12
Figure 15 FP-524D Software Flowchart ........................................................................................................... 14
Figure 16 Replaceable Combustible Gas Sensor............................................................................................... 30
List of Tables
Table 1 Wire Gauge vs. Distance......................................................................................................................... 9
Table 2 Gas/Cal Factors ..................................................................................................................................... 21
Shipping Address: 4055 Technology Forest Blvd, Suite 100, The Woodlands Texas 77381
Mailing Address: P.O. Box 8067, The Woodlands Texas 77387-8067
Phone: [phone] • Fax: [phone] • www.detcon.com • [e-mail]

Model FP-524D
FP-524D Instruction Manual Rev. 1.6 Page 1 of 39
1. Introduction
1.1 Description
Detcon Model FP-524D LEL Combustible 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 a
standard analog 4-20mA output. 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.
MODEL FP-524D
HOUSTON, TEXAS
MicroSafe LEL Gas Sensor
PGM 1
PGM 2
FLT 1 2 CAL
ALM ALM
TM
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. This 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.

Model FP-524D
FP-524D Instruction Manual Rev. 1.6 Page 2 of 39
Main Housing Insert
Printed Circuit Board
Gold Plated Pins
Platinum Wire
Construction
of Detector
Bead
Catalyst
Alumina Bead Catalytic Beads
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
Zero
Adjust
Output
Input
Voltage
Compensator /
Reference Bead
Detector /
Active Bead
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.
Figure 4 Response Curves

Model FP-524D
FP-524D Instruction Manual Rev. 1.6 Page 3 of 39
1.2 Modular Mechanical Design
The Model FP-524D Sensor Assembly is completely modular and is made up of four parts:
1) FP-524D Plug-in Transmitter
2) Field Replaceable Combustible Gas Sensor
3) Connector PCB
4) Splash Guard.
FP-524D 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 pre-
amplifier, sensor temperature control, on-board power supplies, microprocessor, LED display, magnetic
programming switches, and a linear 4-20mA DC output. Magnetic program switches located on either side of
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.
Figure 5 Circuit Functional Block Diagram
PGM 1
PGM 2
Model FP-524D
HOUSTON, TEXAS
FLT 1 2 CAL
MicroSafe LEL Gas Sensor
ALM ALM
TM
Figure 6 FP-524D Transmitter Module
Field Replaceable Sensor
The Detcon combustible gas sensor is a field proven, replaceable type sensor. It can be accessed and replaced
in the field by unthreading the lower half of the sensor housing. The cell can then be unplugged and replaced.
The Detcon combustible gas sensor has an infinite shelf life and is supported by a 2 year warranty.
I/O
Circuit
Protection
4-20mA
Display
Micro-
Processor
Temperature
Control
Pre-Amp
Analog 4-20mA Out
Power In
Power Supply
Plug-In
Sensor
Element

Model FP-524D
FP-524D Instruction Manual Rev. 1.6 Page 4 of 39
Replacable Sensor
Main Housing
Threaded Insert O-ring
Figure 7 LEL Sensor Housing with replaceable 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 Connector PCB
The base connector board is mounted in the Junction Box. The connector board includes lug-less terminal
connections for incoming power and MA output, and connections for the Combustible Gas Replaceable
Sensor.
Customer
Wiring
Wiring to
LEL Sensor
Figure 8 Base Connector Board

Model FP-524D
FP-524D Instruction Manual Rev. 1.6 Page 5 of 39
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 the sensor facing down. When
applying Teflon tape, do not apply to all threads - only use enough to make a good seal (covering
about ½ the threads is sufficient). A metal to metal connection is required to ensure earth ground
continuity for electrical safety.
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 housing bottom and plug-in sensor are installed during operation. The housing bottom
should be threaded tightly to the sensor housing. Removal of the housing bottom 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.
NOTE: Methane and Hydrogen are lighter than air. Most other combustible gases are heavier
than air. Compare the molecular weight, density, or specific gravity of the target gas(es) with
that of air to determine appropriate placement.

Model FP-524D
FP-524D Instruction Manual Rev. 1.6 Page 6 of 39
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 to 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.
NOTE: In all installations the gas sensor should point straight down (refer to Figure 10).
Improper sensor orientation may result in false readings and permanent sensor damage.
Additional Placement Considerations
The sensor should not be positioned where it may be sprayed or coated with surface contaminating substances.
Painting sensor assemblies is prohibited.
Although the sensor is designed to be RFI resistant, it should not be mounted in close proximity to high-
powered 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

Model FP-524D
FP-524D Instruction Manual Rev. 1.6 Page 7 of 39
the active detector’s catalytic ability and cause a permanent reduction in the span sensitivity. Examples of
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-524D 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.
NOTE: Do not use Teflon Tape or any other type of Pipe Thread material on the ¾” threads
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.)
PGM 1
PGM 2
MODEL FP-524D
HOUSTON, TEXAS
FLT 1 2 CAL
MicroSafe LEL Gas Sensor
ALM ALM
TM
5.5"
6.1"
9.03"
2"
5.8"
4.65"
34
NPT Ports
14
" mounting holes
Wall (or other
mounting surface)
LEL Sensor
Splash Guard
2.1"
Figure 9 Typical Outline and Mounting Dimensions
2.5 Electrical Installation
The Sensor Assembly should be installed in accordance with local electrical codes. The sensor assemblies are
CSA/NRTL approved (US and Canada) for Class I, Division 1, Groups B, C, & D area classifications.

Model FP-524D
FP-524D Instruction Manual Rev. 1.6 Page 8 of 39
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.
NOTE: If a conduit run exits the secondary port, repeat the installation technique shown in
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.
NOTE: For products utilizing the aluminum junction box option, the conduit seal shall be
placed at the entry to the junction box (see Figure 10 as an example). For products utilizing the
stainless steel junction box option, the conduit seal shall be placed within 18" of the enclosure.
Crouse Hinds type EYS2, EYD2 or equivalent are suitable for this purpose.
NOTE: The Detcon Warranty does not cover water damage resulting from water leaking into
the enclosure.
Drain
Conduit
"T" EYS Seal Fitting
PGM 1
PGM 2
MODEL FP-524D
HOUSTON, TEXAS
FLT 1 2 CAL
MicroSafe LEL Gas Sensor
ALM ALM
TM
Figure 10 Typical Installation
NOTE: Any unused ports should be blocked with suitable ¾” male NPT plugs. Detcon
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.

Model FP-524D
FP-524D Instruction Manual Rev. 1.6 Page 9 of 39
2.6 Field Wiring
Detcon Model FP-524D combustible gas sensor assemblies require three conductor connections between
power supplies and host electronic controller’s 4-20mA output. A 250 ohm load resistor is needed on the 4-20
mA line when it is not being used. Wiring designations are DC+, DC-, and MA (sensor signal). The
maximum wire length between sensor 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
Over-Current
Protection
22
0.723mm
700
2080
3A
20
0.812mm
1120
3350
5A
18
1.024mm
1750
5250
7A
16
1.291mm
2800
8400
10A
14
1.628mm
4480
13,440
20A
NOTE 1: Wiring table is based on stranded tinned copper wire and is designed to serve as a
reference only.
NOTE 2: Shielded cable is required for installations where cable trays or conduit runs include
high voltage lines or other possible sources of induced interference. Separate conduit runs are
highly recommended in these cases.
NOTE 3: The supply of power should be from an isolated source with over-current protection
as stipulated in table.
NOTE 4: A 250 ohm load resistor is needed on the 4-20 mA line when it is not being used.
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.
Customer
Wiring
White
Blue
Yellow
Black
Wiring to
LEL Sensor
Figure 11 Sensor Connector PCB
a) Remove the junction box cover and unplug the Transmitter Module. Identify the terminal blocks for
customer wire connections.

Model FP-524D
FP-524D Instruction Manual Rev. 1.6 Page 10 of 39
b) Observing correct polarity, terminate the 3-conductor 4-20mA field wiring (DC+, DC-, and MA) 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.
NOTE: A 6-32 or 8-32 threaded exterior ground point is provided on most junction boxes for
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-524D sensor in a remote-mount configuration in which the sensor (Model FP-524D-RS) and
the transmitter (Model FP-524D-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

Model FP-524D
FP-524D Instruction Manual Rev. 1.6 Page 11 of 39
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.
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.
NOTE: Refer to section 3.5.5 to set the sensor bridge voltage.
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-524D 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.
NOTE: The 4-20mA signal is held constant at 4mA for the first two minutes after power up.
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.
NOTE: Do not use calibration gases in Nitrogen background gas mixtures. This will cause
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.

Model FP-524D
FP-524D Instruction Manual Rev. 1.6 Page 12 of 39
3. Operation
3.1 Programming Magnet Operating Instructions
The Operator Interface of the FP-524D Series 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, thereby eliminating 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.
PGM 1
PGM 2
MODEL FP-524D-HRT
HOUSTON, TEXAS
FLT 1 2 CAL
MicroSafe LEL Gas Sensor
ALM ALM
TM
Program 1
Program 2
Figure 14 Magnetic Programming Switches
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.
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.)

Model FP-524D
FP-524D Instruction Manual Rev. 1.6 Page 13 of 39
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
Alarm 1 Level
Alarm 1 Ascending
Alarm 1 Latching
Alarm 2 Level
Alarm 2 Ascending
Alarm 2 Latching
Fault Latching
Set AutoSpan Level
Set Gas Factor
Set Cal Factor
Set Bridge Voltage
Signal Output Check
Restore Default Settings
Alarm 1 Settings
Alarm 2 Settings
Fault Settings

Model FP-524D
FP-524D Instruction Manual Rev. 1.6 Page 14 of 39
Software Flowchart
dec
PGM1/2 (M)
mA Output XX.XX
Sensor Temp XX C
Voltage XX.X VDC
Gas Factor
Sensor Life XXX%
Bridge Current
Bridge Voltage
PGM1/2 (3)
PGM1 (3)
PGM1 (3) PGM2 (3)
Version X.XX
AutoSpan @ XX
Range XXX ppm
Last Cal XX Days
inc
Auto Time-Out
View Sensor Status
PGM1/2 (3)
PGM1/2 (M)
Model Type
PGM2 (3)
PGM1 (S)
PGM1/2 (3)
PGM2 (S)
Auto Time-Out
Set Cal Factor
##
AutoTime-out
PGM1/2 (3)
PGM1/2 (M)
Set AutoSpan Level
Calibration Mode
(Auto Span)
Normal Operation
PGM1/2 (M)PGM1/2 (M)
Simulation
PGM2 (10) PGM1/2 (10)
Signal Output Check
Auto Time-Out
Auto Time-Out
Auto Time-Out
Set Bridge Voltage
inc
PGM1/2 (3)
PGM2 (S)
PGM1 (S)
#.##
PGM1/2 (3)
PGM1/2 (M)
Set Gas Factor
dec
PGM1/2 (M)
Defaults Restored
PGM1/2 (10)
Restore Defaults
Auto Time-Out
PGM1/2 (3)
inc
PGM1/2 (3)
PGM2 (S)
PGM1 (S)
##
dec
inc
PGM1/2 (3)
PGM2 (S)
PGM1 (S)
#.##
dec
Calibration Mode
(Auto Zero)
Cal Factor
LEGEND:
PGM1 - Program Switch Location #1
PGM2 - Program Switch Location #2
inc - Increase
dec - Decrease
#, ##, ### - numeric values
Auto Time-Out
inc PGM1/2 (3)
PGM1/2 (M)
Auto Time Out
Alarm 1 Ascending
PGM1/2 (3)
PGM1/2 (M)
Alarm 1 Level
inc ##
dec
Y/N
inc PGM1/2 (3)
PGM1/2 (M)
Auto Time Out
Alarm 1 Latching
Y/N
Auto Time-Out
inc PGM1/2 (3)
PGM1/2 (M)
Auto Time Out
Alarm 1 Ascending
PGM1/2 (3)
PGM1/2 (M)
Alarm 1 Level
inc ##
dec
Y/N
inc PGM1/2 (3)
PGM1/2 (M)
Auto Time Out
Alarm 1 Latching
Y/N
inc PGM1/2 (3)
PGM1/2 (M)
Auto Time Out
Dault Latching
Y/N
(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.
Alarm 1 Level
Alarm 1 Latching
Alarm 1 Ascending
Alarm 2 Level
Alarm 2 Latching
Alarm 2 Ascending
Fault Latching
Figure 15 FP-524D Software Flowchart

Model FP-524D
FP-524D Instruction Manual Rev. 1.6 Page 15 of 39
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 on 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 (AutoZero and 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.
NOTE: The zero gas source should have a normal background concentration of 20.9% O2.
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, set flow rate of 200-
500cc/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).
NOTE: Upon entering Calibration Mode, the 4-20mA signal drops to 2mA and is held at this
level until the program returns to normal operation.
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.

Model FP-524D
FP-524D Instruction Manual Rev. 1.6 Page 16 of 39
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.
NOTE 1: Before performing AutoSpan Calibration, verify that the AutoSpan level matches
the span calibration gas concentration as described in Section 3.5.2 Set AutoSpan Level.
NOTE 2: The span gas source must have a normal background concentration of 20.9% O2.
Pure Nitrogen background mixtures are not acceptable! Significant span calibration
inaccuracies will result.
NOTE 3: If the target gas is other than methane, use the appropriate Gas Factor as described
in Section 3.5.3 Set Gas Factor
NOTE 4:To maintain the CSA certification, it must be calibrated on methane.
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).
NOTE: Upon entering Calibration Mode, the 4-20mA signal drops to 2mA and is held at this
level until the program returns to normal operation.
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