Teledyne 8800T User manual

instruction
manual
Teledyne Analytical Instruments
A Business Unit of Teledyne Electronic Technologies
Model 8800T
TRACE MOISTURE ANALYZER

8800T User’sManual
i

8800T User’sManual
ii
8800T User’sManualTable ofContents
1.0 Overviewof the8800T .................................................1
2.1 Precautions using the sensor .........................................3
2.2 Sensor Technical Specifications ...................................4
2.3 Sensor Installation & Sampling Techniques .................4
2.3.1 In-situ Installation ......................................................5
2.3.2 Extractive Installation ................................................7
2.4 Troubleshooting unexpected readings ..........................9
3.1 Precautionsusing the8800T .......................................13
3.1.1 Electromagnetic Compatibility Considerations .......13
3.2 Instrument Technical Specifications ...........................14
3.3 Installation ..................................................................15
3.3.1 Mechanical Installation ............................................15
3.3.2 Electrical Installation ...............................................16
3.4 Operating the Instrument ............................................17
3.4.1 Starting up ................................................................17
3.4.2 Display Conventions ................................................17
3.4.3 Push Buttons ............................................................19
3.4.4 Operating State ........................................................19
3.4.4.1 Viewing Dewpoint Mode ......................................20
3.4.4.2 Viewing Temperature at the Sensor ......................20
3.4.4.3 Start Calibration (SpanCheck™) Mode ................21
3.4.4.4 Viewing Serial Number Mode ..............................24
3.4.5 SetUp State ..............................................................24
3.5 Troubleshooting the Instrument ..................................28
Appendix A: Operating State User Interface flowchart ....31
Appendix B: Set-Up State User Interface flowchart .........32
Appendix C:8800T MechanicalDrawing ........................34
Appendix D:8800T ElectricalConnections.....................35
Appendix E: Sensor/SpanCheck™ Theory of Operation .36
Appendix F: Pressure Correction ......................................39
Appendix G: Current vs. Dewpoint ..................................40

8800T User’sManual
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Appendix H: Uncertainty in LBS & ppmV calculations ..43
Appendix I: Sensor Response Time ..................................44
Appendix J: Return Authorization Request ......................45

Section 1: Introduction
page 1
1.0 Overviewofthe8800T
The8800T isamicroprocessor based 4-20mAloop powered
(2 wire) hygrometer, for measuring moisture content in
gases in the range from -100°C to +20°C. The measurement
is displayed on the instrument’s custom LCD, and is trans-
mitted by varying the current drawn (4-20mA) from the
power supply.The current varies linearly proportional to the
selected measurement units. An optional digital output is
available which modulates/demodulates the 4-20mA loop
line without interfering with its operation. With this option
the8800T iscapableof communicatingwith properly
equipped Personal Computers or other RS-232 capable con-
trollers. Three front panel buttons provide the user with a
widevariety of features. The8800T’sadvanced design
allows it to be housed in a small stainless steel enclosure
behind the sensor probe, thus the instrument and sensor are
a single integrated unit.
The8800T usestheTeledyne HTF™sensor which isencap-
sulated in sintered stainless steel, thus it is capable of com-
ing into contact with a wide variety of environments.
However one should keep in mind that the sensor is a sensi-
tive device and it should be handled accordingly.

8800T User’sManual
page 2

Section 2: Sensor and Sampling Techniques
page 3
2.1 Precautions using the sensor
TheTeledyne HTF™Al2O3sensor isdesigned and field
proven to behighly reliable, rugged and maintenancefree.
However the user should consider the following precau-
tions:
• To avoid the need for prolonged dry-down (when
expecting to measure dewpoints dryer than -65ºC), do
not expose the sensor to room air longer than necessary
(1 - 2 minutes). Thus, do not open the sensor container
before you are ready to install the sensor.
• The sensor container has desiccant to keep the sensor
dry during shipping and to avoid damage due to conden-
sation. Close the container immediately after removing
the sensor to avoid degradation of the desiccant.
• Do not throw away the sensor container, you may use it
again to transport the sensor between locations, to store
it between uses or to ship it back to the factory for certi-
fication. The container can be attached to the loop cable,
by trapping the cable with the lid strap.
• Do not expose the sensor to corrosive gases such as
gases containing chlorine, ammonia or HCl. (SO2 can
be monitored when the moisture content is low).
• Except for the XTR65W sensor:
1. Do not expose the sensor to liquid water, as it may get
damaged.
2. Do not breathe directly onto the sensor, as condensa-
tion may form which could damage the sensor element.
• Do not install the sensor near heat sources such as radia-
tors or air ducts.
• Do not install the sensor in places subject to extreme
mechanical vibration or shock. If this is not avoidable,
use resilient mounting. If in doubt, call your representa-

8800T User’sManual
page 4
tive.
• Do not disassemble the porous metal filter encapsula-
tion, as this will damage the sensor and void your fac-
tory warranty.
• Prior to installation of the probe, ensure that no contam-
inants are present in the system (e.g. oil, liquid water).
2.2 Sensor Technical Specifications
Type: .................................Hyper Thin Film high capacitance Al2O3.
Dewpoint range:
XTR-100........................-148°F to +68°F (-100°C to +20°C)
XTR-65..........................-85°F to +68°F (-65°C to +20°C).
Capacitance:......................15nF to 200nF.
Accuracy:..........................±5.5°F (±3°C).
Repeatability:....................±0.9°F (±0.5°C).
Response time:..................see graph in Appendix I.
Temperature range: ...........-10°C to +70°C.
Sample Flow range:
(linear velocity @ 1ATM):Static to 100m/s.
Storage temperature:.........-40°F to+176°F (-40°C to +80°C).
Mechanical:.......................encapsulated in 100µsintered stainless steel.
Calibration method: ..........SpanCheck™, sensor saturates at dewpoint above
+68°F (+20°C). NIST/NPL traceable multi-point
factory calibration available optionally.
2.3 Sensor Installation & Sampling Techniques
Keep in mind that the moisture content at the sensor is not
only due to the moisture of the gas being measured, but also
due to desorption of water from tubing, trapped moisture (at
the interconnection points, valves, filters and other hygro-
scopic materials in the system), leaks in the system, and oth-
ers. Thus the measurement may vary from the expectation,
and therefore care should be taken in choosing the sampling
technique utilized in the measurement. Factors such as gas
pressure, flow rate, materials of construction, length and

Section 2: Sensor and Sampling Techniques
page 5
diameter of tubing, number of interconnecting fittings, dead
space in tubing and manifolds; will influence the measure-
ment value and response time.
The highcapacitance HTF™ sensors can be installed either
directly in the lineto be sampled (in-situ), or in a slip stream
of a sample system (extractive).
To assure a long and accurate performance of the sensor, it
should be protected from contaminants such as liquids
(water, oil etc.), and particulates. The sintered stainless steel
sensor encapsulation protects from particulates larger than
100 microns, finer particulates (e.g. from degraded desic-
cant or rust) should be filtered with a particulate filter with
suitable capability, do not use hygroscopic filter materials.
2.3.1 In-situ Installation
In-situ installation is recommended only for measurements
where the gas pressure is expected to vary little, the gas is
expected to be free of contaminants, the gas temperature is
within theoperating specificationsof thesensor, and there is
no chance of liquids coalescing. Examples of applications
suited for in-situ installations are: pure gases, output of des-
iccant dryers (for instrument air), glove boxes, etc. For most
other applications in-situ installation should be avoided for
the following reasons:
• Sample conditioning is almost always necessary to
avoid exposure of the sensor to liquid water and other
contaminants, such as hydrocarbons, which may dam-
age the sensor or affect accuracy over time.
• Variations in line pressure affect the reading of the sen-
sor because dewpoint varies with pressure.
• If the gas line is under pressure, it is more likely that
water condensation occurs which may damage the sen-
sor.

8800T User’sManual
page 6
• Under a pressurized system removal of the sensor with-
out the installation of isolation valves can be dangerous.
If in-situ installation is required, bypass mounting is prefer-
able; make sure to install the sensor at the upper surface of
the gas line to minimize its exposure to liquid water, should
condensation occur, the XTR65W sensor is best suited for
these applications. Also consider the need to isolate (depres-
surize) before installing or removing the sensor.
Main
Gas Line
8800T
8800T
4-20mA loop cable
Safety shut-off Valve
Bypass
Control
Valve *
Safety shut-off Valve
Bypass Installation, Sensor
Measuring at Line Pressure
In-Line Installation, Sensor
Measuring at Line Pressure
Main
Gas Line
4-20mA loop cable
oint Transmitter
Ma
Se
Mo
Think
Safety
Read
Manual
www.xentaur.com NOT RECOMMENDED
Sample Cell
oint Transmitter
Ma
Se
Mo
Think
Safety
Read
Manual
www.xentaur.com
* maintain differential pressure to provide adequate flow through sample cell

Section 2: Sensor and Sampling Techniques
page 7
2.3.2 Extractive Installation
For extractive installations we recommend our sample sys-
tem ESS, which may be equipped with a variety of features,
such as: isolation valve, coalescing or particulate filter,
pressure regulator, calibration sample injection or extraction
port, pressure gauge, flow meter, weatherproof enclosure.
Refer to the ESS literature for more information.
If the resources to make your own sample system are avail-
able, the following two diagrams may be used as aguideline
to configure a simple system.
8800T
4-20mA loop cable Exhaust
Regulator or
Needle Valve
Safety shut-off Valve
Extractive Installation, Sensor
Measuring at Line Pressure
8800T
4-20mA loop cable
Exhaust
Regulator or
Needle Valve
Extractive Installation, Sensor
Measuring at Ambient Pressure
Sample Cell
oint Transmitter
Ma
Se
Mo
Think
Safety
Read
Manual
www.xentaur.com
Sample Cell
oint Transmitter
Ma
Se
Mo
Think
Safety
Read
Manual
www.xentaur.com
Main
Gas Line
Main
Gas Line

8800T User’sManual
page 8
It is generally recommended to measure at ambient pressure
for the following reasons:
• The readings will not be affected by variations in line
pressure.
• The risk of exposing the sensor to liquid water is signif-
icantly reduced.
• ppm readings are computed for a pressure of one atmo-
sphere (1 bar); and have to be corrected using software
in the instrument, or a pressure nomograph, or calcula-
tor if the sensor is measuring at different pressures.
If readings at line pressure are necessary, it is recommended
to measure at ambient pressure and to use the instrument’s
pressure compensation feature to calculate the dewpoint at
line pressure. See appendix F.
Please make sure that:
• The sample is taken from the upper surface of the main
gas line. This avoids problems with contamination. The
sample should betaken away frompipe line walls where
flow rates may be low, and dewpoint changes may lag.
• For dewpoints dryer than -40°F, use stainless steel tub-
ing only. Copper tubing is acceptable for dewpoints wet-
ter than -40°F. Do notuse plastic, rubber or tygon tubing
under any circumstances, as measurements would be
incorrect and/or response time slow due to water reten-
tion inside these materials.
• Try to run pipes to the sensor upwards, so that contami-
nants tend to fall back into the main line.
• Keep the length of the sample line to the sensor as short
as possible.
• Use small diameter pipes (1/4” or 1/8” OD).
• Use sufficient flow rates (e.g. 1 l/min with 6 feet of 1/8”
piping is adequate). The flow rate will influence the sys-
tems’ response time.

Section 2: Sensor and Sampling Techniques
page 9
• Do not install any devices upstream of the sensor, such
as other measuring systems, flow meters etc., which are
not absolutely necessary as these are potential leak
sources.
• Installation of a coalescing and / or particulate filter
ahead of the sensor is desirable to prevent any liquid or
particulate contamination of the sensor.
• If filters are used upstream of the sensor, make sure
these contain non-hygroscopic filter materials only.
• If pressure regulators, shut off valves etc. are used
upstream of the sensor, make sure these do not contain
rubber or other hygroscopic materials.
2.4 Troubleshooting unexpected readings
If erroneous readings are suspected on a newly acquired
instrument, compare the serial number engraved on the sen-
sor sintered filter, to the one stored in the instrument mem-
ory. The two should be the same; if they are not, the
instrument may not be calibrated with the installed sensor.
To troubleshoot other problems, identify the unexpected
reading category in the following table, and consider the
possible causes and appropriate diagnostic action and rem-
edy.

8800T User’sManual
page 10
Troubleshooting unexpected readings (table spans 2 pages)
For non-sensor related problems (e.g. no reading on instru-
ment) refer to section 3.5
Symptom Possible Cause
Reading is not
changing Condensation in sample system.
Slow Response 1. Water vapor in the system. 2. Flow rate too low.
3. Sample pipe too large and/or too long.
4. Unsuitable sample pipematerial.
5. Leaks
6. Hygroscopic materials in sample system
Dry Reading SpanCheck™ wrongly set, or faulty sensor.
Wet Reading Leak in system or use of unsuitable pipe.
Comparison of readings with manual cooled-
mirror instrument.
Display Shows
6$7
Prolonged exposure to wet gas.
Display Shows
6+5
1. Instrument Failure
2.Short circuited sensor.
Display Shows 1. Instrument failure.
231
2. Open circuit on sensor.

Section 2: Sensor and Sampling Techniques
page 11
Troubleshooting unexpected readings (continued from previous page)
Symptom Diagnostic/Remedy
Reading is not
changing
Condensation will occurif the temperature of the sample system, at any point is below
(colder) the dewpoint temperature of the sample gas. Once having formed, the sample
reaching the sensor will have a dewpoint equal to the temperature of the condensation,
regardless of the dewpoint of the sample at the sample point.
Slow Response It is usually more satisfactory to bleed a sample gas at atmospheric pressure through the sensor sampling chamber, and to use 1/8” (3mm) o.d. sample pipe.
See below re: sample pipe material, also see section 2.3
Dry Reading Verify SpanCheck™, or return sensor for full calibration to your representative.
Wet Reading Cure the leak, or replace unsuitable pipe with copper or stainless steel. Flexible con- nections should be made with PTFE pipe. NEVER use rubber or plastic pipe.
This type of indicator reads about 10°C dry at about -50°C dewpoint due to tempera-
ture gradients within the device. The error increases at drier levels.
Display Shows
6$7
Dry the sensor, install sensor in either a known dry gas stream i.e. instrument quality
air or dry nitrogen, or place sensor in a dry can or bottle of desiccant and seal the con-
tainer from outside air (the shipping container is designed for this purpose)
Display Shows
6+5
Remove (unscrew) sensor, if the instrument still reads 6+5 the problem is with the
instrument. However, if the instrument reads 231 then check possible cause #2
Remove (unscrew) sensor and note that the meter reading returns to 231. Use a new
sensor, or apply approximately 20V DC, between the center pin & the filter body of
the sensor, MOMENTARILY with the sensor in a known dry condition.Polarity is not
important, but the contact MUST be very brief or the sensor may be damaged.
Display Shows
Remove(unscrew)thesensor.Shortthecentercontactofthe8800T sensorconnection
to the case, if the instrument reads 6+5 the problem is in the sensor, otherwise return
the instrument for service.
231
Check sensor connection or replace sensor.

8800T User’sManual
page 12

Section 3: Instrument
page 13
3.1 Precautions using the8800T
The8800T usesstate-of-the-artmicroelectronicsto provide
a miniature full functioning instrument. The user should
consider the following precautions when usingany sensitive
electronic device.
• Do not install the unit near heat sources such as radia-
tors or air ducts.
• Do not install the unit in places subject to extreme
mechanical vibration or shock. If this is not avoidable,
use resilient mounting. If in doubt, call your representa-
tive.
• Observe the appropriate electrical safety codes and reg-
ulations
• If weather proofing is required consult your representa-
tive for an optional cover.
3.1.1 Electromagnetic Compatibility Considerations
The8800T hasbeen designed and verified by testing to
meet the requirements of the EC Council EMC Directive
89/336/EEC, for Industrial, Scientific & Medical equip-
ment. Thesensor ground (8800T housing) isisolated from
the 4-20mA loop, however they are also shunted with a
2000pF capacitor and a 33V Transient Voltage Suppressor;
this prevents electrostatic buildup, noise pick-up, and in
conjunction with the internal fuse protects the instrument
from over-voltage inputs. Please consider the following
electromagnetic interference issues during installation:
• In order to provide an acceptable noise environment for
the8800T or any other digitalequipmentin theproxim-
ity of inductive loads, it is recommended that there be
varistors placed across the inductors to keep down the
high voltage spikes during transitions.

8800T User’sManual
page 14
• Any circuitry which is activated by relay contacts
should account for the contact bounce, one simple
debouncing method is placing a capacitor across the
relay contacts.
• AC power wiring should be routed as far away from the
8800T and itswiring aspractical.
3.2 Instrument Technical Specifications
Enclosure:.........................Stainless Steel, optional weather proof cover is avail-
able.
Dimensions & Weight:......~2”Dia. x ~4.75” long including sensor & connector
(see appendix C) 0.5lbs.
Pressure operating range:..Standard:.....500 PSI (34 bar).
Optional:.....5,000 PSI (340 bar).
Mechanical connections:...14mm x 1.25mm threads, and ¾”-16 threads.
Electrical connections:......2.1mm x 5.5mm (12mm minimum barrel length)
power jack, with retainer.
Cable:................................Two conductor cable, 12’ (~4m) provided.
Power Requirements:........10 to 33 VDC polarity independent, the instrument
draws 4-20mA depending on measured dewpoint.
Input resolution:................0.1°C dewpoint.
Indicators:.........................3.5 digit LCD with custom legends.
Engineering units:.............°C,°F, PPM, LBS H2O/mm scf,gm H2O/M3.
Controls:............................3 push buttons, user’s selections are stored in
EEPROM.
Outputs:.............................Analog and digital outputs are available from the
8800T.
A.4-20mA drawn by the instrument fromthe power
supply. The 4-20mA is linear to the selected engi-
neering units, the range is programmable. Output
resolution is 0.1°C dewpoint.
B. The instrument can supply digital output by
modulating the 4-20mA loop line. The timing and
format of the data conforms to RS-232, however to
interface to a PC or other RS-232 device an optional
adapter is required.
In the digital mode the 8800T can be remotely
operated and the dewpoint as well as temperature

Section 3: Instrument
page 15
(and pressure if installed) can be read.
In the digital mode multiple units can operate on
the same loop cable as a multi-channel instrument.
Alarms:..............................The 4-20mA signal or the digital output may be used
by an external device to operate relays.
Isolation:...........................Sensor and case are isolated from the current loop
but are shunted with a 33V transorb and 2000pF
capacitor.
3.3 Installation
3.3.1 Mechanical Installation
The8800T hastwo thread sizesformounting to thesample
cavity (consult the sensor installation section) where the
dewpoint will be measured. Various adapters are available
for direct connection into existing system openings. Ask
your representative for a Sample Cell, if you do not have the
ability to provide an appropriate sample cavity mounting. If
the¾”x16 thread isused then the8800T willseal againstthe
wall of the sample cell with the provided Viton A O-ring. If
the 14mm x 1.25 spark plug thread is used then an addi-
tional Viton gasket must be installed to provide the proper
seal. Ask your representative for this gasket, it is available
freeof charge. The8800T islightenough such thateither
thread will mechanically support the whole instrument. To
preventany leaks, tighten the8800T into thesamplecavity,
with a 17/8” wrench, 1/8 turn past finger-tight to assure
metal-to-metal contact.
Sincethetightened positioning of the8800T isunpredict-
able, its front panel may be rotated (360°) to allow easy
reading of the display. Press down gently on the spring
loaded face plate and turn it to the desired position.
Thesensor can beremoved fromthe8800T by unscrewing
it. Make sure that the sensor is securely fastened to the

8800T User’sManual
page 16
8800T (thetension washer should becompressed), so thatit
does not come loose during use.
3.3.2 Electrical Installation
The8800T willoperateproperly with 10VDC to 33VDC at
its input, if this voltage is exceeded the internal fuse may
blow. When selecting the power supply voltage do not
neglect the drop across any current measurement resistor
and wiring in theloop. Theconnector isastandard 2.1mmx
5.5mm (12mm minimum barrel length) DC power jack, an
internal diode bridge accommodates either polarity. The
8800T may bepowered using an off-the-shelf wall trans-
former with 2.1mm connector, or from a power supply
using the provided connectorized cable. The provided cable
is terminated with a connector which has a retainer, the
retainer may beused to securetheconnector to the8800T
thus avoiding accidental disconnection.
The8800T willdraw4mAto 20mAfromthepower supply
depending on the dewpoint being measured. The dewpoints
corresponding to 4mA and to 20mA are user selectable, in
between the current will vary linearly to the selected engi-
neering units, see appendix G.
Variousstrategiesfor interfacingwith the8800T areshown
in Appendix D.
Please observe good electrical safety and grounding prac-
tices when connecting any electrical equipment; connecting
one end (e.g. negative) of the power supply to earth ground
is advisable.
After the installation is complete, proper detection by the
user’s equipment of the 4-20mA output, may be tested using
theAnalog Outputtestfeatureof the8800T, seesection
3.4.5.6.