Oldham 700 TP Series User manual

OLCT 700/710 TP
The Fixed Gas Detection Experts
Instruction Manual
700 TP Series
Hydrogen Sulfide Detector
Solid State Sensor
Part Number: NP700TPIMEN
Revision: C.1
OLCT 700
OLCT 710

OLCT 700/710 TP
ii OLCT 700/710 TP
Copyright Februaryl 2019 by Oldham S.A.S.
All rights reserved. No reproduction of all or part of this document, in any form,
is permitted without the written consent of Oldham S.A.S.
All of the information that is provided in this document is accurate to the best of
our knowledge.
As a result of continuous research and development, the specifications of this
product may be changed without prior notice.
Oldham S.A.S.
Rue Orfila
Z.I. Est –CS 20417
F –62027 ARRAS Cedex
Tel: [phone]
Fax: [phone]

OLCT 700/710 TP
OLCT 700/710 TP iii
Table of Contents
1. Introduction...........................................................................................................................................1
1.1 Description.......................................................................................................................................1
1.2 Modular Mechanical Design............................................................................................................ 2
1.3 Plug-in Replaceable Sensor .............................................................................................................3
2. Installation .............................................................................................................................................5
2.1 ATEX Operational Guidelines for Safe Use................................................................................5
2.2 Functional Safety (SIL 2) ..............................................................................................................6
2.3 Detector Placement........................................................................................................................6
2.4 Sensor Contaminants and Interference .......................................................................................7
2.5 Mounting Installation....................................................................................................................8
2.6 Electrical Installation.....................................................................................................................9
2.7 Field Wiring..................................................................................................................................10
2.8 Initial Start Up ............................................................................................................................. 12
3. Operation .............................................................................................................................................15
3.1 Programming Magnet Operating Instructions .........................................................................15
3.2 Operator Interface.......................................................................................................................16
3.3 Normal Operation........................................................................................................................17
3.4 Calibration Mode (AutoSpan) ....................................................................................................17
3.5 Program Mode .............................................................................................................................19
3.6 Program Features ........................................................................................................................24
4. RS-485 Modbus™ Protocol ................................................................................................................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
6. Troubleshooting Guide .......................................................................................................................31
7. Appendix..............................................................................................................................................35
7.1 Specifications................................................................................................................................35
7.2 Spare Parts, Detector Accessories, Calibration Equipment.....................................................37
7.3 OLCT 700710 TP Drawings........................................................................................................38
8. EC Declaration of conformity ............................................................................................................41
9. Revision Log......................................................................................................................................... 43

OLCT 700/710 TP
iv OLCT 700/710 TP
Table of Figures
Figure 1: Detector Assembly Breakaway............................................................................................................. 2
Figure 2: Detector Assembly Front View ............................................................................................................ 2
Figure 3: Vue de face de l’OLCT 710.................................................................................................................. 3
Figure 4: OLCT 700/710 TP Plug-in Sensor Cell................................................................................................ 3
Figure 5: ATEX Approval Label.......................................................................................................................... 5
Figure 6: Outline and Mounting Dimensions....................................................................................................... 8
Figure 7: Typical Installation ............................................................................................................................... 9
Figure 8: Detector Wire Connections................................................................................................................. 12
Figure 9: Magnetic Programming Tool.............................................................................................................. 15
Figure 10: Magnetic Programming Switches..................................................................................................... 15
Figure 11: OLCT 700/710 TP Software Flowchart............................................................................................ 17
Figure 12: Detector Assembly............................................................................................................................ 29
Figure 13: Sensor PCB....................................................................................................................................... 31
List of Tables
Table 1: Cross Interference Gases........................................................................................................................ 7
Table 2: Wire Gauge vs. Distance...................................................................................................................... 10
Table 3: Modbus™ Registers............................................................................................................................. 27
Table 4: Modbus™ Special Registers ................................................................................................................ 28

OLCT 700/710 TP
OLCT 700/710 TP v
Thank you for choosing this OLDHAM instrument. All of the necessary actions have been taken in order
to ensure your complete satisfaction with this equipment. It is important that you read this entire manual
carefully and thoroughly.
Limitation of Reliability
▪OLDHAM shall not be held responsible for any damage to the equipment or for any physical injury or
death resulting in whole or in part from the inappropriate use, installation, or storage of the equipment,
which is the result of not complying with the instructions and warnings, and/or with the standards and
regulations in force.
▪OLDHAM does not support or authorise any business, person, or legal entity in assuming responsibility
on behalf of OLDHAM, even though they may be involved in the sale of OLDHAM products.
▪OLDHAM shall not be responsible for any damage, direct or indirect, or for damages and interest,
direct or indirect, resulting from the sale and use of any of its products UNLESS SUCH PRODUCTS
HAVE BEEN DEFINED AND CHOSEN BY OLDHAM FOR THE USE THAT THEY ARE
INTENDED.
Ownership clauses
▪The drawings, specifications, and information herein contain confidential information that is the
property of OLDHAM.
▪This information shall not, either in whole or in part, by physical, electronic, or any other means
whatsoever, be reproduced, copied, divulged, translated, or used as the basis for the manufacture or sale
of OLDHAM equipment, or for any other reason without the prior consent of OLDHAM.
Warning
▪This is not a contractual document. In the best interest of its customers and with the aim of improving
performance, OLDHAM reserves the right to alter the technical features of its equipment without prior
notice.
▪READ THESE INSTRUCTIONS CAREFULLY BEFORE THE FIRST USAGE: these
instructions should be read by all persons who have or will have responsibility for the use, maintenance,
or repair of the instrument.
▪This instrument shall only be deemed to be in conformance with the published performance if used,
maintained, and repaired in accordance with the instructions of OLDHAM by OLDHAM personnel or
by personnel authorised by OLDHAM.
Guarantee
▪Under normal conditions of use and on return to the factory, sensors are guaranteed for 5 years and
electronics parts are guaranteed for 2 years from date of shipment; excluding consumables as
dessiccant, filters, etc.
Destruction of the equipment
European Union (and EEA) only. This symbol indicates that, in conformity with directive DEEE
(2002/96/CE) and according to local regulations, this product may not be discarded together with
household wasteIt must be disposed of in a collection area that is set aside for this purpose, for
example at a site that is officially designated for the recycling of electrical and electronic
equipment (EEE) or a point of exchange for authorized products in the event of the acquisition of a new
product of the same type as before.

OLCT 700/710 TP
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OLCT 700/710 TP
OLCT 700/710 TP Instruction Manual Rev. C.1 Page 1 of 45
1. Introduction
1.1 Description
Oldham OLCT 700 TP hydrogen sulfide gas transmitters are
non-intrusive “Smart” detectors designed to detect and monitor
H2S in air. Ranges of detection are 0-20ppm, 0-50ppm, 0-
100ppm, and 0-200ppm. The detector features an LED display
of current reading, fault and calibration status. The detector is
equipped with standard analog 4-20mA and Modbus™ RS-485
outputs. A primary feature of the detector 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
detector readings, and the detector’s menu driven features when
the hand-held programming magnet is used.
The OLCT 710 is made of an OLCT 700 attached to a flameproof junction that includes terminal blocks
and an optional surge protection board. The complete assembly is flameproof certified « Ex d » and carries
ATEX approval (see section 2.1- ATEX Operational Guidelines for Safe Use).
The OLCT 700 is flameproof certified and carries ATEX approval. The OLCT 700 shall be attached to an
increased safety certified junction box when used in an ATEX zone (see section 2.1- ATEX Operational
Guidelines for Safe Use).
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 sensor film 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 5-year
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.
OLCT 710
OLCT 700

OLCT 700/710 TP
Page 2 of 45 Rev. C.1 OLCT 700/710 TP Instruction Manual
1.2 Modular Mechanical Design
The OLCT 700 TP Detector Assembly is completely modular and is made up of four parts (See Figure
below):
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
MODEL
TP-700
detcon inc.
H2S Sensor
SplashGuard
Figure 1: Detector Assembly Breakaway
1) Intelligent Transmitter Module (ITM). The Intelligent Transmitter Module (ITM) is a fully
encapsulated microprocessor-based package that accepts a plug-in field replaceable H2S sensor.
Circuit functions include LED display, magnetic programming switches, a linear 4-20mA DC
output, and a Modbus™ RS-485 output. Magnetic program switches allow non-intrusive operator
interface
2) Field Replaceable Plug-in H2S Gas Sensor
3) 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.
Program Switch #1
LED Display
Program Switch #2
MODEL
TP-700
detcon inc.
H2S Sensor
Splash Guard Adapter
Locking Set-Screw
Figure 2: OLCT 700 Assembly Front View
OLDHAM
OLCT
700 TP
OLDHAM
OLCT
700 TP
Housing Bottom
Assembly

OLCT 700/710 TP
OLCT 700/710 TP Instruction Manual Rev. C.1 Page 3 of 45
OLCT 710 is made of an OLCT 700 attached to a flameproof certified junction box for terminal
connections.
Figure 3: ’OLCT 710 Front View
1.3 Plug-in Replaceable Sensor
The Oldham 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 Oldham solid state H2S
sensor has an infinite shelf life and is supported by a 5 year, industry-leading warranty.
Figure 4: OLCT 700/710 TP Plug-in Sensor Cell
M34 - ¾ NPT Adapter
Locking Screw
Cover
Locking Screw

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OLCT 700/710 TP
OLCT 700/710 TP Instruction Manual Rev. C.1 Page 5 of 45
2. Installation
2.1 ATEX Operational Guidelines for Safe Use
OLCT 700/710 conforms to the requirements of European Directive ATEX 94/9/CE relating to explosive
Gas atmospheres.
The information given in the following sections should be respected and taken into account by the manager
of the site where the equipment is installed. As far as the aim of improving the health and safety of workers
who are exposed to the risks of explosive atmospheres is concerned, refer to European Directive ATEX
1999/92/CE.
1. Install detector 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. Cable glands shall be flameproof certified («Ex d») for use in explosive atmospheres. Ingress
Protection will be greater or equal to IP66. Cable glands will be mounted according to IEC/EN
60079-14 standard, edition in force, and to additional requirements from local standards. They
shall be of M20x1.5 and the engagement shall be 5 threads at least. Cables used shall have an
operating temperature range equal or greater than 80 °C.
3. The threaded joints may be lubricated to maintain flameproof protection. Only non-hardening
lubricants or non-corrosive agents having no volatile solvents may be used.
4. Verify a good ground connection between the junction box and earth ground.
5. Ensure the Housing Bottom is 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.
6. Removal of the Housing Bottom violates the Ex d protection method and hence power must be
removed from the detector prior its safe removal.
7. Proper precautions should be taken during installation and maintenance to avoid the build-up of
static charge on the plastic components of the detector. These include the splashguard and
splashguard adapter.
8. When used in ATEX zone, OLCT 700 shall be attached to increased safety certified junction box
only.

OLCT 700/710 TP
Page 6 of 45 Rev. C.1 OLCT 700/710 TP Instruction Manual
2.2 Functional Safety (SIL 2)
Refer to safety user manual NP700TPSMEN
2.3 Detector Placement
Selection of detector location is critical to the overall safe performance of the product. Six factors play an
important role in selection of detector 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 detectors relative to the density of the target gas is such that detectors 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, detector 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 detectors 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 detector 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 detector should point straight down (refer to Figure 7).
Improper detector orientation may result in false readings and permanent detector damage.
Additional Placement Considerations
The detector should not be positioned where it may be sprayed or coated with surface contaminating
substances. Painting detector assemblies is prohibited.
Although the detector is designed to be RFI resistant, it should not be mounted in close proximity to high-
powered radio transmitters or similar RFI generating equipment.

OLCT 700/710 TP
OLCT 700/710 TP Instruction Manual Rev. C.1 Page 7 of 45
When possible mount the detector in an area void of high wind, accumulating dust, rain or splashing from
hose spray, direct steam releases, and continuous vibration. If the detector cannot be mounted away from
these conditions then make sure the Oldham Harsh Environment Splashguard accessory is used (PN DET-
943-002273-000).
Do not mount in locations where temperatures will exceed the operating temperature limits of the detector.
Where direct sunlight leads to exceeding the high temperature-operating limit, use a sunshade to help
reduce temperature.
2.4 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
Reading
(ppm)
GAS
PPM
Reading
(ppm)
Methane
25000
0
Ammonia
500
1
Ethane
5000
0
Diesel Fuel
1000
0
Hexane
5000
0
Dimethyl Sulfide
4,4
0
Propane
5000
0
Ethylene
200
0
Butane
5000
0
Freon 12
1000
0
Carbon Monoxide
800
0
Hydrogen
1000
8
Carbon Dioxide
5000
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 Oldham MOS Sensor 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.
NOTE: Always protect the sensor with the Oldham Sealing Cap and a fresh desiccant packet
when the detector is powered off, this will avoid permanent sensor damage and help preserve
the span calibration.

OLCT 700/710 TP
Page 8 of 45 Rev. C.1 OLCT 700/710 TP Instruction Manual
2.5 Mounting Installation
▪The installation should meet all the regulations currently in force for installations in explosive
atmospheres, in particular the standards IEC/EN 60079-14 and IEC/EN 60079-17 (whichever editions
are in force) or in accordance with other national standards.
▪The equipment is allowed in ATEX zones 1 and 2 for ambient temperatures ranging from -40 °C to +
75 °C. Understand that operating temperature range may be different (see technical specifications).
▪The sensor shall always be in contact with ambient air. Therefore,
- do not cover the detector
- do not paint detector assemblies
- avoid dust accumulation
The OLCT 700/710 TP should be vertically oriented so that the detector points straight downward (see
Figure below). Installation of the enclosure shall be secured with 4 x M6 screws and the appropriate plugs
for the supporting material. There is an adaptor plate for ceiling installation (PN 6322420).
Figure 6: Outline and Mounting Dimensions
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 Oldham J-box accessories are available
separately).
Ground
Ground

OLCT 700/710 TP
OLCT 700/710 TP Instruction Manual Rev. C.1 Page 9 of 45
2.6 Electrical Installation
The installation should meet all the regulations currently in force for installations in explosive
atmospheres, in particular the standards IEC/EN 60079-14 and IEC/EN 60079-17 (whichever editions are
in force) or in accordance with other national standards. OLCT 700 and OLCT 710 are certified for use in
ATEX zones 1 and 2, group IIB+H2, T4.
Proper electrical installation of the gas detector is critical for conformance to Electrical Codes and to avoid
damage due to water leakage. Refer to Figure 7 and Figure 8 for proper electrical installation.
Figure 7: Typical Installation
NOTE: The Oldham Warranty does not cover water damage resulting from water leaking into
the enclosure. 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 detector would not be expected.
NOTE: Unused port should be blocked with the M20x1.5 male plug supplied by Oldham
(ATEX and ‘Ex d IIC’ certified). The engagement shall be 5 threads at least.
Unused port shall be
sealed with the « Ex d »
certified plug delivered
along with the transmitter.

OLCT 700/710 TP
Page 10 of 45 Rev. C.1 OLCT 700/710 TP Instruction Manual
2.7 Field Wiring
Oldham OLCT 700/710 TP solid-state H2S detector 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 + (24 VDC), –(0 V), mA (detector signal),
and Modbus™ RS-485 A (+), and B (-). Maximum wire length between detector and 24VDC source is
shown in the Table below. Maximum wire size for termination in the Oldham J-Box accessory is 14 gauge.
Max loop load resistance between green and black wire (analog signal output) is 500 ohms. Minimum loop
load resistance between green and black wire is 100 ohms. This is considers wire diameter, wire length,
max operating temperature and selected termination resistor.
Table 2: Wire Gauge vs. Distance
AWG
Wire Dia.
Cross Section
Meters/Feet
Over-Current
Protection
22
0,65 mm
0,32 mm²
700/2080
3A
20
0,8 mm
0,5 mm²
1120/3350
5A
18
1,0 mm
0,8 mm²
1750/5250
7A
16
1,3 mm
1,3 mm²
2800/8400
10A
14
1,6 mm
2 mm²
4480/13440
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 or tray
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.
2.7.1 Cable Preparation
NOTE : It is essential that the instructions provided by the manufacturer of the cable gland are
followed and the braid is correctly connected.
1 - Remove the rubber pot and the two metal washers
(A)
2 - Arrange the cable as shown in the picture

OLCT 700/710 TP
OLCT 700/710 TP Instruction Manual Rev. C.1 Page 11 of 45
3 –Arrange the braid as shown in the picture. Avoid
creating "pigtails"
4 - Insert the part back into the OLCT 710
2.7.2 Terminal Connections
CAUTION:Do not apply System power to the detector until all wiring is properly terminated and
openings are properly closed.
a) Remove the junction box cover. Identify the terminal blocks for customer wire connections (see Figure
8).
NOTE : To remove the cover, tighten the locking screw before unscrewing the cover
Locking screw

OLCT 700/710 TP
Page 12 of 45 Rev. C.1 OLCT 700/710 TP Instruction Manual
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 8: Detector Wire Connections
b) Observing correct polarity, terminate the 3-conductor 4-20mA field wiring (+, -, and mA) to the
detector assembly wiring in accordance with the detail shown in Figure 8.
NOTE: If the 4-20mA output is not being used, the Green wire from the detector must be
connected to the Black wire at the (-) terminal on the Transient Protection Module to
ensure RS-485 communication is not disrupted by a 4-20mA Fault.
c) If applicable, terminate the RS-485 serial wiring. 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 detector
and host PC. General Cable Commodore part number ZO16P0022189 is recommended.
NOTE: Install a 120Ω resistor across A & B terminals on the last detector in the serial loop.
d) Screw the cover firmly and loosen the locking screw until it reaches the cover.
2.8 Initial Start Up
Upon completion of all mechanical mounting and termination of all field wiring, apply system power in
the range of 11.5-30VDC (24VDC typical).
NOTE: A desiccant cap with a desiccant packet is attached to the sensor 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.
Remove the desiccant cap about 10 minutes after applying power to the detector and install the
weatherproof splashguard accessory supplied with the detector.
NOTE: Store the desiccant caps with the desiccant packets in a sealed container (i.e. zip-lock
bag) for future use. It is advisable to reinstall the desiccant cap and packet during prolonged
periods without power (more than 1 day is considered “prolonged”). An active desiccant packet
is blue in color and turns pink when consumed (PN DET-960-240010-000).

OLCT 700/710 TP
OLCT 700/710 TP Instruction Manual Rev. C.1 Page 13 of 45
In the absence of fault messages (flashing display), OLCT 700/710 TP display reads “0”. A temporary
upscale reading may occur as the detector 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 detector.
NOTE: The 4-20mA signal is held constant at 4mA for the first two minutes after power up.
2.8.1 Initial Operational Tests
After a warm up period of 1 hour, the detector should be checked to verify sensitivity to H2S gas.
Material Requirements
•PN DET-613-120000-700 OLCT 700/710 Splash Guard with integral Cal Port OR PN DET943-
000006-132 Threaded Calibration Adapter
•PN 18108087 Span Gas; 25ppm H2S in balance Air (10ppm for 0-20ppm range)
•PN DET-985-241100-321 In-Line Humidifying Tube
NOTE: Do not use H2S in Nitrogen background gas mixtures. This will cause significant
reading inaccuracies.
NOTE: Span gas bottles contain 0% humidity and this ultra-low humidity condition will cause
inaccurate readings when used to calibrate a detector. To prevent this error, Oldham prescribes
the use of the In-Line Humidifying Tube.
a) Connect the In-Line Humidifying Tube between the cal gas cylinder and the detector. 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 detector housing. Apply the test gas at a controlled flow
rate of 0.5l/min max. Allow 1-2 minutes for the reading to stabilize. Observe that during the 1-2
minutes the OLCT 700/710 display increases to a level near that of the applied calibration gas value.
c) Remove test gas and observe that the display decreases to “0”.
Initial operational tests are complete. Oldham H2S gas detectors 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.

OLCT 700/710 TP
Page 14 of 45 Rev. C.1 OLCT 700/710 TP Instruction Manual