Chilled Mirror Instruments
S8000
Precision Chilled Mirror Hygrometer
A high-precision hygrometer combining straightforward operation with very high sensitivity to
changes in moisture content.
Highlights
• ±0.1°Cdp (±0.18°Fdp) accuracy
• Fundamental, accurate and drift-free measurement
• Simple confi guration and operation via touch screen
interface
• Precision measurements to –60°C (–76°F) dew point
• FAST – guaranteed frost formation below 0°C
(+32°F)
• Measure at pressures up to 2 MPa (20 barg)
• USB, Ethernet, RS485 or RS232 connectivity
• Datalogging to SD card or via digital comms
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Applications
• Standards laboratory reference instrument
• Transformer vacuum drying verifi cation
• Clean/dry room environmental monitoring
• Metallurgical process monitoring
• Reference instrument for commercial calibration
laboratory
• Compressed air dryer R&D
switchgear moisture testing
• SF
6
• Hydrogen fuel cell R&D
Chilled Mirror Instruments
S8000
Precision Chilled Mirror Hygrometer
The new S8000 Hygrometer provides a direct measurement
of dew point, temperature and pressure. Dew-point
measurement is based on the proven, fundamental optical
chilled mirror measurement principle, giving long-term
drift-free humidity measurement over the entire operating
range. The S8000 uses this measurement to offer a range
of available measurement units including ppmV, absolute
humidity, relative humidity and ppmW.
To further improve the accuracy of pressure-derived
calculated values (ppm
optional internal pressure transducer can be supplied,
which provides real-time pressure. This allows for continued
humidity measurement stability even during fl uctuations in
sample pressure.
, ppmW, absolute humidity), an
V
The difference in vapor pressure between condensed water
and ice formed on a chilled mirror can introduce dewpoint errors of up to 10% of reading. It is also possible
for intermediate states to exist, where the formation is a
mixture of ice and super-cooled water, making calculated
conversions from one state to the other invalid.
Frost Assurance Technology (FAST)
The S8000 features FAST, the frost assurance technology
which guarantees all dew-point measurements below 0°C
(+32°F) are made over ice. The FAST system works by
detecting whether the mirror is at a temperature where
super cooled water could form, and if so; rapidly cooling the
mirror until a fi lm of ice of predetermined thickness forms.
Once ice has formed, control returns to the instrument and
measurement can begin.
Microscope
A viewing microscope can be supplied with the instrument.
This enables the user to inspect the mirror directly during
the measurement process, and determine whether the
condensation on the surface is water or ice.
Use your Preferred Communications
Media
For greater fl exibility:
A pair of adjustable isolated alarm contacts allow the S8000
Chilled Mirror Hygrometer to be used for direct process
control. A high-contrast touch screen LCD display provides
entirely customizable local indication of the measured values,
along with a trend graph and fault warnings.
RRS Triple Optics for Increased
Sensitivity
The rate of frost formation on the surface of a chilled mirror
is slower at lower frost points. This is due to the very low
quantity of water molecules which are present – it takes
time for enough molecules to pass the mirror to form a layer
of frost. An accurate and reliable measurement with a nonfundamental hygrometer can be diffi cult to perform.
The S8000 utilizes the RRS Optical System to detect very
small changes in the quantity of moisture condensed on
the mirror surface, resulting in very high sensitivity and fast
response to changes in frost point, even at low levels of
moisture.
Confi dence of Seeing your Measurement
In carefully controlled laboratory conditions, super-cooled
water can exist in temperatures as low as –48°C (–54°F).
However, when using a chilled mirror instrument it only
occurs on the mirror at temperatures down to around –30°C
(–22°F).
• Modbus TCP over Ethernet
• Modbus RTU over: USB, RS232, RS485
• Datalogging to SD Card or via application software
• 3 user-confi gurable analog outputs
• Status and process alarms
DCC for Increased Reliability
The S8000 utilizes a system called DCC (Dynamic
Contamination Correction). The DCC system is intuitive and
adapts the instrument control to the operating conditions to
achieve optimum measurement performance at all times by
periodically re-balancing the optics to compensate for any
reduction in light intensity caused by contamination of the
components in the optical path. Although the DCC system is
fully automatic it can be confi gured by the user for individual
applications.
Application Software
Flexible application software is provided with the S8000,
allowing the operator to control all the functions of the
instrument directly from a PC. A parameter display shows
all measured and calculated parameters, and a customizable
graph is provided to display any combination of parameters
against a time base.
Data logging functionality is provided, allowing log fi les to be
created and saved directly on the host PC.
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