Detcon TP-700 User manual

INSTRUCTION MANUAL
Detcon Model TP-700
TP-700 Hydrogen Sulfide Sensor
This manual covers the following ranges:
0-20ppm, 0-50ppm, 0-100ppm and 0-200ppm
DETCON, Inc.
4055 Technology Forest Blvd.,
The Woodlands, Texas 77381
Ph.281.367.4100 / Fax [phone]
www.detcon.com
June 05, 2018 • Document #3150 • Revision 4.1

Model TP-700
Model TP-700 ii
This page left intentionally blank

Model TP-700
Model TP-700 iii
Table of Contents
1. Introduction ..................................................................................................................................................1
1.1 Description.......................................................................................................................................... 1
1.2 Sensor Electronics Design .................................................................................................................. 1
1.3 Modular Mechanical Design............................................................................................................... 2
1.4 Plug-in Replaceable Sensor ................................................................................................................ 3
2. Installation....................................................................................................................................................4
2.1 ATEX Operational Guidelines for Safe Use....................................................................................... 4
2.2 Sensor Placement................................................................................................................................ 5
2.3 Sensor Contaminants and Interference ............................................................................................... 6
2.4 Mounting Installation.......................................................................................................................... 7
2.5 Electrical Installation .......................................................................................................................... 9
2.6 Field Wiring...................................................................................................................................... 10
2.7 Initial Start Up................................................................................................................................... 12
2.7.1 Initial Operational Tests ............................................................................................................... 13
3. Operation....................................................................................................................................................14
3.1 Programming Magnet Operating Instructions................................................................................... 14
3.2 Operator Interface............................................................................................................................. 15
3.3 Normal Operation ............................................................................................................................. 16
3.4 Calibration Mode (AutoSpan)........................................................................................................... 17
3.5 Program Mode .................................................................................................................................. 19
3.5.1 Navigating Program Mode ........................................................................................................... 19
3.5.2 View Sensor Status....................................................................................................................... 20
3.5.3 Set AutoSpan Level...................................................................................................................... 21
3.5.4 Set Range...................................................................................................................................... 21
3.5.5 Set Serial ID ................................................................................................................................. 22
3.5.6 Set Heater Power .......................................................................................................................... 22
3.5.7 Signal Output Check..................................................................................................................... 23
3.5.8 Restore Factory Defaults .............................................................................................................. 23
3.6 Program Features .............................................................................................................................. 24
3.6.1 Operational Features..................................................................................................................... 24
3.6.2 Fault Diagnostic/Failsafe Features ............................................................................................... 24
4. RS-485 Modbus™ Protocol .......................................................................................................................27
Content Description.............................................................................................................................................27
5. Service and Maintenance............................................................................................................................29
5.1 Calibration Frequency....................................................................................................................... 29
5.2 Visual Inspection .............................................................................................................................. 29
5.3 Condensation Prevention Packet....................................................................................................... 29
5.4 Replacement of Plug-in H2S Sensor ................................................................................................. 29
5.5 Replacement of ITM......................................................................................................................... 30
5.6 Replacement of TP-700 Sensor Assembly........................................................................................ 31
5.7 Replacement of the Bottom Housing................................................................................................ 31
6. Troubleshooting Guide...............................................................................................................................32
7. Customer Support and Service Policy........................................................................................................35
7.1 Warranty Notice................................................................................................................................ 35
8. TP-700 Sensor Warranty............................................................................................................................36
8.1 Plug-in H2S Sensor Warranty ........................................................................................................... 36
8.2 ITM Electronics Warranty................................................................................................................ 36
8.3 Terms & Conditions.......................................................................................................................... 36
9. Appendix ....................................................................................................................................................37
9.1 Specifications.................................................................................................................................... 37

Model TP-700
Model TP-700 iv
9.2 Spare Parts, Sensor Accessories, Calibration Equipment................................................................. 39
10. Revision Log......................................................................................................................................... 40
Table of Figures
Figure 1 ITM Circuit Functional Block Diagram................................................................................................. 2
Figure 2 Sensor Assembly Front View ............................................................................................................... 2
Figure 3 Sensor Assembly Breakaway................................................................................................................. 3
Figure 4 TP Plug-in Sensor Cell........................................................................................................................... 3
Figure 5 ATEX Approval Label........................................................................................................................... 4
Figure 6 Outline and Mounting Dimensions (Sensor Assembly only)................................................................. 7
Figure 7 Outline and Mounting Dimensions (Stainless Steel Junction Box)....................................................... 8
Figure 8 Outline and Mounting Dimensions (Aluminum Junction Box)............................................................. 8
Figure 9 Outline and Mounting Dimensions (Mini Stainless Steel Junction Box) .............................................. 9
Figure 10 Typical Installation ............................................................................................................................ 10
Figure 11 Sensor Wire Connections................................................................................................................... 11
Figure 12 Magnetic Programming Tool............................................................................................................. 14
Figure 13 Magnetic Programming Switches...................................................................................................... 14
Figure 14 TP-700 Software Flowchart............................................................................................................... 16
Figure 15 Sensor Assembly................................................................................................................................ 29
Figure 16 Sensor PCB........................................................................................................................................ 32
List of Tables
Table 1 Cross Interference Gases......................................................................................................................... 6
Table 2 Wire Gauge vs. Distance....................................................................................................................... 11
Table 3 Modbus™ Registers.............................................................................................................................. 27
Table 4 Modbus™ Special Registers ................................................................................................................. 28
Shipping Address: 4055 Technology Forest Blvd., The Woodlands Texas 77381
Mailing Address: P.O. Box 8067, The Woodlands Texas 77387-8067
Phone: [phone] • Fax: [phone] • www.detcon.com • [email protected]m

Model TP-700
TP-700 Instruction Manual Rev. 4.1 Page 1 of 42
1. Introduction
1.1 Description
Detcon Model TP-700 hydrogen sulfide sensors are non-intrusive “Smart” sensors
designed to detect and monitor H2S in air. Ranges of detection are 0-20ppm, 0-50ppm,
0-100ppm, and 0-200ppm. The sensor features an LED display of current reading, fault
and calibration status. The Sensor is equipped with standard analog 4-20mA and
Modbus™ RS-485 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 in an encapsulated module and
housed in an explosion proof casting, called the ITM (Intelligent Transmitter Module).
The ITM 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.
Solid State H2S Sensor Technology
The sensor technology is a patented solid-state mixed metal oxide semiconductor.
The sensor consists of two thin films, a temperature sensitive heater film, and a
hydrogen sulfide sensitive sensor film. Both films are deposited on a silicon
microchip by vacuum deposition. The heater film elevates the operating temperature
of the sensorfilm to a level where a good sensitivity and response to hydrogen sulfide
is achieved. The sensor film is a proprietary mixed metal oxide that shows an
extremely stable and dynamic response to hydrogen sulfide gas.
Range of sensitivity is from parts per billion to percent by volume. The rugged
sensor is capable of maintaining its operating characteristics for periods of up to 7-
10 years in most industrial environments and as such, is supported by a 10-year
conditional warranty.
Principle of Operation
Method of detection is by diffusion/adsorption. Air and H2S diffuse through a sintered stainless steel filter
(flame arrestor) and contact the heated surface of the metal oxide sensor film. As hydrogen sulfide gas molecules
react with oxygen ions on the film, there is a decrease in electrical resistance proportional to the gas
concentration. The heater film elevates the temperature of the sensor film creating convection and promoting a
quick response to changing gas concentrations. Electronically, the heater film is used to maintain a constant
temperature of the sensor film enhancing stability and repeatability. The sensor response is reversible and results
in continuous monitoring of ambient air conditions.
1.2 Sensor Electronics Design
Intelligent Sensor Module
The Intelligent Transmitter Module (ITM) is a fully encapsulated microprocessor-based package that accepts a
plug-in field replaceable H2S sensor. Circuit functions include extensive I/O circuit protection, sensor pre-
amplifier, sensor temperature control, on-board power supplies, microprocessor, LED display, magnetic
programming switches, a linear 4-20mA DC output, and a Modbus™ RS-485 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 ITM. Calibration can be accomplished without

Model TP-700
TP-700 Instruction Manual Rev. 4.1 Page 2 of 42
declassifying the area. Electrical classifications are Class I, Division 1, Groups B, C, D, Class I, Zone 1, Group
IIB+H2and II 2G Ex d IIB+H2Gb.
Figure 1 ITM Circuit Functional Block Diagram
Program Switch #1
LED Display
Program Switch #2
Splash Guard Adapter
Locking Set-Screw
MODEL
TP-700
detcon inc.
H 2 S Sensor
Figure 2Sensor Assembly Front View
1.3 Modular Mechanical Design
The Model TP-700 Sensor Assembly is completely modular and is made up of four parts (See Figure 3 for
Assembly Break-away):
1) TP-700 Intelligent Sensor Module (ITM)
2) Field Replaceable Plug-in H2S Gas Sensor
3) Model 700 Housing Bottom Assembly (contains the Housing Bottom, Flame Arrestor, Retaining Ring,
and rubber O-Ring’s)
4) Splash Guard.
NOTE: All metal components are constructed from electro polished 316 Stainless Steel in order to maximize
corrosion resistance in harsh environments.
I/O
Circuit
Protection
RS-485
4-20mA
Display
Micro-
Processor
Temperature
Control
Pre-Amp
Analog 4-20mA Out
Modbus™ RS-485 Output
Power In
Power Supply
Plug-In
Sensor
Element

Model TP-700
TP-700 Instruction Manual Rev. 4.1 Page 3 of 42
O-Rings
Splash Guard
Adapter Plug-in Replaceable
H2S Sensor Lens and LED
Display Interconnect
Wires
Housing Bottom
Locking Set-Screw Intelligent Transmitter Module (ITM)
Micro-processor controlled circuit
encapsulated in an Explosion proof
housing.
Magnetic
Programming
Switches
SplashGuard
MODEL
TP-700
detcon inc.
H
2
S Sensor
Figure 3 Sensor Assembly Breakaway
1.4 Plug-in Replaceable Sensor
The Detcon solid-state H2S gas sensor is a field proven, plug-in replaceable type sensor with over-sized gold-
plated connections that eliminate corrosion problems. It can be accessed and replaced in the field very easily by
releasing the locking screw and unthreading the housing bottom. The Detcon solid state H2S sensor has an
infinite shelf life and is supported by a 10 year, industry-leading warranty.
Figure 4 TP Plug-in Sensor Cell

Model TP-700
TP-700 Instruction Manual Rev. 4.1 Page 4 of 42
2. Installation
2.1 ATEX Operational Guidelines for Safe Use
1. Install sensor only in areas with classifications matching with those described on the ATEX approval
label. Follow all warnings listed on the label.
Figure 5 ATEX Approval Label
2. Ensure that the sensor is properly threaded into a suitable flameproof rated junction box with a
downward pointing female ¾” NPT threaded connection. The sensor should be threaded up at least 5
full turns until tight, with the LED display facing forward (+/-15°). Minimize use of Teflon Tape, or
any type of non-conductive pipe thread coating on the NPT threaded connection.
3. A good ground connection should be verified between the sensor’s metal enclosure and the junction
box. If a good ground connection is not made, the sensor can be grounded to the junction box using the
sensor’s external ground lug. Also verify a good ground connection between the junction box and earth
ground. Installer shall use ring terminal to make connection to earth ground to be secured by screw and
lockwasher on sensor housing.
4. Ensure that the Housing Bottom and plug-in sensor are installed during operation. The Housing Bottom
should be threaded tightly to the Intelligent Transmitter Module. The locking setscrew(M3.5 x 0.6 6g6h
Stainless Steel Allen set screw cup point with yield strength of greater than 40,000 PSI, typical 80,000
PSI) should then be tightened down to keep the Housing Bottom from being inadvertently removed or
from becoming loose under vibration. The locking setscrew ensures that Housing Bottom is only
removable by authorized personnel with the use of special tools. A M1.5 Allen Wrench is required. If
screw requires replacement, only an identical screw may be used.
5. Removal of the Housing Bottom violates the Ex d protection method and hence power must be removed
from the sensor prior to its safe removal.
6. The screws holding down the retaining plate label are special fasteners of type Stainless Steel, Phillips
Pan-head Machine screw, M3 x 0.56g6h having yield strength ofgreater than 40,000 PSI, typical 80,000
PSI. If screw requires replacement, only an identical screw may be used.
7. 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.
8. Do not operate the sensor outside of the stated operating temperature limits.
9. Do not operate the sensor outside the stated operating limits for voltage supply.
10. These sensors meet EN60079-0:2012, EN60079-1:2007.
M/Y:
S/N:
RATED11
-30VDC, 85mA MAX
T4
T amb = -40° C to +75°C, IP66
0035
KEMA 06ATEX2152X
WARNING: KEEPCOVER TIGHT WHILECIRCUITS
ARE ALIVE. WARNING: UNDERSTANDMANUAL
ORIGIN USA

Model TP-700
TP-700 Instruction Manual Rev. 4.1 Page 5 of 42
2.2 Sensor Placement
Selection of sensor location is critical to the overall safe performance of the product. Five factors play an
important role in selection of sensor locations:
(1) Density of the gas to be detected
(2) Most probable leak sources within the industrial process
(3) Ventilation or prevailing wind conditions
(4) Personnel exposure
(5) Maintenance access
(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: H2S is heavier than air.
Leak Sources
The most probable leak sources within an industrial process include flanges, valves, and tubing connections of
the sealed type where seals may either fail or wear. Other leak sources are best determined by facility engineers
with experience in similar processes.
Ventilation
Normal ventilation or prevailing wind conditions can dictate efficient location of gas sensors in a manner where
the migration of gas clouds is quickly detected.
Personnel Exposure
The undetected migration of gas clouds should not be allowed to approach concentrated personnel areas such as
control rooms, maintenance or warehouse buildings. A more general and applicable thought toward selecting
sensor location is combining leak source and perimeter protection in the best possible configuration.
Maintenance Access
Consideration should be given to providing easy access for maintenance personnel. Consideration should also
be given to the consequences of close proximity to contaminants that may foul the sensor prematurely.
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.

Model TP-700
TP-700 Instruction Manual Rev. 4.1 Page 6 of 42
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 Environment Splashguard 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
Solid State H2S 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 more common materials that potentially cause problems with the sensors are as follows:
•Silicone vapors such as those found in greases and lubricants
•Halide Compounds containing Chlorine, Chlorine Dioxide, Fluorine, HF, HCl, and Bromine
•Caustic and Acid liquids and concentrated vapors
•Heavy metals such as tetraethyl lead
The presence of such contaminants in an area does not preclude the use of this H2S 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.
Solid State H2S sensors require O2in the background gas and the reading is affected by changing O2 levels.
Interference Data
There are some gases typically found in industrial environments that can cause a cross-interference response on
the sensor. See the Table below for some examples.
Table 1 Cross Interference Gases
GAS PPM GAS PPM
Methane
25,000 = 0
Ammonia
500 = 1
Ethane
5,000 = 0
Diesel Fuel
1000 = 0
Hexane
5,000 = 0
Dimethyl Sulfide
4.4 = 0
Propane
5,000 = 0
Ethylene
200 = 0
Butane
5,000 = 0
Freon 12
1,000 = 0
Carbon Monoxide
800 = 0
Hydrogen
1,000 = 8
Carbon Dioxide
5,000 = 0
Methyl Mercaptan
10 = 5
Carbon Disulfide
14 = 0
Sulfur Dioxide
300 = 0
Methanol
500 = 5
Toluene
32 = 0
Isopropanol
500 = 3
Ethanol
500 = 5
NOTE: The Detcon MOS Sensor Cell can be damaged to the point of non-functioning if the
unit is left off power and in the presence normal air levels of moisture for periods exceeding 8
hours.

Model TP-700
TP-700 Instruction Manual Rev. 4.1 Page 7 of 42
NOTE: Always protect the sensor cell with the Detcon Sealing Cap and a fresh desiccant packet
when the sensor is powered off, this will avoid permanent sensor cell damage and help preserve
the span calibration.
2.4 Mounting Installation
The TP-700 sensor assembly is designed to be threaded into a ¾” Female NPT fitting of a standard cast metal,
Explosion-Proof Enclosure or Junction Box. Thread the sensor up until tight (5 turns is typically expected) and
until the display is pointed in the direction that sensor will normally be viewed and accessed.
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.
The TP-700 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. Detcon provides a standard
selection of junction boxes available as sensor accessories (See Figures 6, 7, 8, and 9 below), but any
appropriately rated enclosure with a downward facing ¾” Female NPT connection will suffice.
When mounting on a wall, it is recommended to use a 0.25”-0.5” spacer underneath the mounting ears of the
Detcon standard J-Box to offset the sensor assembly from the wall and create open access around the sensor
assembly. Spacing requirements for other junction boxes may vary.
Male 3/4" NPT Threads
Sensor Assembly
Splash Guard
2.125"
7.8"
Typ.
Ferrite Cylinder
Sensor Wires
2"
0.3"
5.48"
MODEL
TP-700
detcon inc.
H
2 S Sensor
Figure 6Outline and Mounting Dimensions (Sensor Assembly only)

Model TP-700
TP-700 Instruction Manual Rev. 4.1 Page 8 of 42
4"
3/4" NPT
Explosion Proof Enclosure
Junction-Box
Sensor Assembly
Splash Guard
(Detcon's SS Junction-Box shown)
2.125"
5.5"
12.5"
Typ.
Mounting
Bolt
Use Spacers to move the J-Box
and Sensor Assembly away
from the wall at least 0.25-0.5"
to allow access to Sensor.
Wall
(or other
mounting surface)
Ø0.265"
Spacer
Mounting Holes
8-32 Thread
Ground Point
MODEL
TP-700
detcon inc.
H
2 S Sensor
Figure 7Outline and Mounting Dimensions (Stainless Steel Junction Box)
4"
3/4" NPT
Explosion Proof Enclosure
Junction-Box
Sensor Assembly
Splash Guard
(Detcon's Aluminum Junction-Box shown)
2.125"
5.5"
13.05"
Typ.
Mounting
Bolt
Use Spacers to move the J-Box
and Sensor Assembly away
from the wall at least 0.25-0.5"
to allow access to Sensor
Wall (or other
mounting surface)
Ø0.265" x2
Spacer
Mounting Holes
8-32 Thread
Ground Point
MODEL
TP-700
detcon inc.
H 2 S Sensor
Figure 8 Outline and Mounting Dimensions (Aluminum Junction Box)

Model TP-700
TP-700 Instruction Manual Rev. 4.1 Page 9 of 42
3.5"
Explosion Proof Enclosure
Junction-Box
Sensor Assembly
Splash Guard
(Detcon's Mini SS Junction-Box shown)
2.125"
3.45"
11"
Typ.
Mounting Holes
8-32 Thread
Ground Point
Ø0.4" x .475"
MODEL
TP-700
detcon inc.
H
2 S Sensor
Figure 9 Outline and Mounting Dimensions (Mini Stainless Steel Junction Box)
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 J-box accessories are available separately.)
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, and are
ATEX Approved for Class I, Zone 1, Group IIB+H2area classifications.
Proper electrical installation of the gas sensor is critical for conformance to Electrical Codes and to avoid damage
due to water leakage. Refer to Figure 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.

Model TP-700
TP-700 Instruction Manual Rev. 4.1 Page 10 of 42
Plug any unused
ports
Explosion Proof
Housing
(J-Box)
Drain
TP-700
Sensor
Assembly
Conduit
"T" EYS Seal Fitting
(+)
mA
(-)
A(+)
B(-)
Wiring to
Sensor Assembly
Wht
Blu
Red
Grn
Blk
Explosion
Proof
Junction Box
(+)
mA
(-)
N/U
A(+)
B(-)
Customer
Supplied Wiring
Transient Protection Module
(TPM) P/N 500-003087-100
Mount TPM in Explosion
Proof Enclosure to ground
unit properly. Mount to
bottom of enclosure using
6-32 screws.
+
6-Pin Pheonix Plug
P/N 306-175705-100
MODEL
TP-700
detcon inc.
H
2 S Sensor
Figure 10 Typical Installation
NOTE: For products utilizing the aluminum junction box option, the conduit sealshallbe 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 through the conduit connections. However, since the electronics are 100% epoxy
encapsulated, only the wire terminations could get wet. Moisture could cause abnormal
operation and possibly corrosion to the terminal connections, but permanent damage to the sensor
would not be expected.
NOTE: Any unused ports should be blocked with suitable ¾” male NPT plugs. Detcon Supplies
one ¾” NPT male plug with their accessory J-box enclosures. If connections are other than ¾”
NPT, use an appropriate male plug of like construction material.
2.6 Field Wiring
Detcon Model TP-700 solid-state H2S sensor assemblies require three conductor connections between power
supplies and host electronic controller’s 4-20mA output, and 2 conductor connections for the Modbus™ RS-485
serial interface. Wiring designations are + (DC), – (DC), mA (sensor signal), and Modbus™ RS-485 A (+), and
B (-). Maximum wire size for termination in the Detcon J-Box accessory is 14 gauge.

Model TP-700
TP-700 Instruction Manual Rev. 4.1 Page 11 of 42
Table 2 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.
Terminal Connections
CAUTION:Do not apply System power to the sensor until all wiring is properly terminated. Refer to
Section 2.7 Initial Start Up
CAUTION: Do not apply power to the sensor assembly in a hazardous area unless the junction box
cover is tight and all electrical seals have been installed
Customer
Supplied Wiring
(Out to next Device)
(+)
mA
(-)
A(+)
B(-)
Wiring to
Sensor Assembly
Wht
Blu
Red
Grn
Blk
Explosion
Proof
Junction Box
(+)
mA
(-)
A(+)
B(-)
(+)
mA
(-)
A(+)
B(-)
Customer
Supplied Wiring (In)
Modbus RS-485 to
Host Control Device
Power from and 4-20mA
out to Control Device
Install a 100-250 Ohm
resistor if the 4-20mA
output is not used
Modbus RS-485 to
next Device
Figure 11 Sensor Wire Connections

Model TP-700
TP-700 Instruction Manual Rev. 4.1 Page 12 of 42
a) Remove the junction box cover. Identify the terminal blocks for customer wire connections.
b) Observing correct polarity, terminate the 3-conductor 4-20mA field wiring (+, -, and mA) to the sensor
assembly wiring in accordance with the detail shown in Figure 11. If the 4-20mA output is not used, the
green wire from the sensor must be connected to the (-) terminal on the Transient Protection Module.
NOTE: If the 4-20mA output is not being used, the Green wire from the sensor must be
connected to the Black wire at the (-) terminal on the Transient Protection Module to
ensure proper sensor operation.
c) If applicable, terminate the RS-485 serial wiring as shown in Figure 11. Use the second plug (Out) as
termination point on the customer side to facilitate a continuous RS-485 serial loop.
The RS-485 (if applicable) requires 24 gauge, two conductor, shielded, twisted pair cable between sensor and
host PC. General Cable Commodore part number ZO16P0022189 is recommended.
NOTE: Install a 120Ω resistor across A & B terminals on the last sensor in the serial loop.
d) Trim all exposed wire leads if they are not permanently landed in the terminal block.
e) Replace the junction box cover.
NOTE: A 6-32 threaded exterior ground point is provided on the sensor housing for an external
ground. If the Sensor Housing is not mechanically grounded, an external ground strap must be
used to ensure that the sensor is electrically grounded.
2.7 Initial Start Up
CAUTION: Do not apply power to the sensor assembly in a hazardous area unless the junction box
cover is tight and all electrical seals have been installed
Upon completion of all mechanical mounting and termination of all field wiring, apply system power in the
range of 11.5-30VDC (24VDC typical) and observe the following normal conditions:
a) TP-700 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”
ppm within 1-2 minutes of power-up, assuming there is no gas in the area of the sensor.
NOTE: A desiccant cap with a desiccant packet is attached to the sensor cell housing to avoid
damage during storage and shipping. This prevents water from contacting the sensor film, and
as a result helps to retain the stability of the factory span calibration.
c) Remove the desiccant cap about 10 minutes after applying power to the sensor and install the weatherproof
splashguard accessory supplied with the sensor.
IMPORTANT NOTE: Do not remove the desiccant cap and cover until power is applied to the
sensor. Store the desiccant caps with the desiccant packets in a sealed container (i.e. zip-lock
Bag) for future use. It is mandatory to reinstall the desiccant cap and packet during any periods
without power lasting more than 1 hour. An active desiccant packet is blue in color and turns

Model TP-700
TP-700 Instruction Manual Rev. 4.1 Page 13 of 42
pink when consumed. (re-order P/N 960-240010-000). Do not use the desiccant packet if it is
pink in color, order new packets as required.
NOTE: The 4-20mA signal is held constant at 4mA for the first two minutes after power up.
2.7.1 Initial Operational Tests
After a warm up period of 1 hour, the sensor should be checked to verify sensitivity to H2S gas.
Material Requirements
•Detcon PN 613-120000-700 700 Series Splash Guard with integral Cal Port -OR-
•Detcon PN 943-000006-132 Threaded Calibration Adapter
•Detcon PN 942-010112-025 Span Gas; 25ppm H2S in balance Air at fixed flow rate between 200 -
500cc/min (10ppm for 0-20ppm range)
•Detcon PN 985-241100-321 In-Line Humidifying Tube
NOTE: Do not use H
2
S in Nitrogen background gas mixtures. This will cause significant reading
inaccuracies.
a) Connect the In-Line Humidifying Tube between the cal gas cylinder and the sensor. The humidifying tube
will introduce the ambient relative humidity into the Cal Gas as it passes through the tube.
b) 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 ITM display increases to a level near that of the applied calibration
gas value.
c) Remove test gas and observe that the ITM display decreases to “0”.
Initial operational tests are complete. Detcon H2S 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 TP-700
TP-700 Instruction Manual Rev. 4.1 Page 14 of 42
3. Operation
3.1 Programming Magnet Operating Instructions
The Operator Interface of the Model 700 Series gas sensors is accomplished via two internal magnetic switches
located to either side of the LED display (see Figure 13). 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 12 Magnetic Programming Tool
The magnetic programming tool (Figure 12) 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 13.
Program Switch #1
LED Display
Program Switch #2
MODEL
TP-700
detcon inc.
H
2S Sensor
Figure 13 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 TP-700
TP-700 Instruction Manual Rev. 4.1 Page 15 of 42
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
AutoSpan
Program Mode
View Sensor Status
Sensor Model Type
Current Software Version
Range of Detection
Serial ID address
AutoSpan Level
Days Since Last AutoSpan
Remaining Sensor Life
Sensor Heater Power
Sensor Heater Voltage
Raw Sensor Resistance
mA Output
Input Voltage Supply
Sensor Temperature
Set AutoSpan Level
Set Range
Set Serial ID
Set Heater Power
Signal Output Check
Restore Default Settings

Model TP-700
TP-700 Instruction Manual Rev. 4.1 Page 16 of 42
Software Flowchart
dec
PGM1/2 (M)
mA Output XX.XX
Sensor Temp XX C
Voltage XX.X VDC
Resistance XXXXX
Sensor Life XXX%
Heater XXX mW
Serial ID XX
Heater X.XX VDC
PGM1/2 (3)
Setting Heater
Exit
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 (10)
PGM2 (S)
PGM1/2 (3)
PGM1 (S)
Auto Time-Out
Set Heater Power
##
AutoTime-out
PGM1/2 (3)
PGM1/2 (M)
Set AutoSpan Level
Calibration Mode
(Auto Span)
Normal Operation
PGM1/2 (M)PGM1/2 (M)
Defaults Restored
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
PGM2 (10)
PGM1/2 (3)
Simulation
PGM1/2 (3)
Auto Time-Out
Restore Defaults
Auto Time-Out
Auto Time-Out
Auto Time-Out
Signal Output Check
inc
PGM1/2 (3)
PGM1 (S)
PGM2 (S)
##
PGM1/2 (3)
PGM1/2 (M)
Set Range
dec inc PGM2 (S)
PGM1/2 (3)
PGM1 (S)
##
dec
PGM1/2 (3)
PGM1/2 (M)
Set Serial ID
Figure 14 TP-700 Software Flowchart
3.3 Normal Operation
In normal operation, the ITM 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. ppm
H2S). If the sensor is actively experiencing any diagnostic faults, a “Fault Detected” message will scroll across
the display on the ITM 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 linearity corresponds with the full-scale range. The RS-485
Modbus™ serial output provides the current gas reading and complete fault status on a continuous basis when
polled by the master device.