Teledyne 8800T User manual

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

8800T User’sManual
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8800T User’sManual
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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

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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
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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
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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.

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• 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