Michell Instruments Easidew PRO I.S., Руководство пользователя

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Easidew PRO I.S. User’s Manual
Michell Instruments 9
OPERATION
3 OPERATION
3.1 Measurement and Confi guration
The Easidew PRO I.S. can be con fi gured to provide an output of 4-20 mA (2-wire
connection) for the following:
Dew point -110 to +20°C (-166 to +68°F)
Moisture content in gas 0 - 3000 ppm
V
Moisture content in liquids 0 - 3000 ppm
W
The Easidew PRO I.S. can be purchased factory con fi gured as required. Alternatively, the
Easidew PRO I.S. can be con fi gured by the customer, using the Easidew Communications
Kit (EPR-CK) and Easidew Application Software. The Easidew Communications Kit can
be purchased from Michell Instruments or a local representative. For a free copy of the
Application Software contact Michell Instruments’ UK of fi ce (see www.michell.com for
details of Michell’s contact information).
For moisture content in gas, the calculation from the measured dew point is assumed to
be at atmospheric pressure. Alternatively, a fi xed gas pressure needs to be programmed
into the Easidew PRO I.S.
For moisture content measurement in liquid, the Easidew PRO I.S. requires the saturation
constant of the liquid to be programmed into the transmitters, either at the factory or
by the customer using the Application Software.
The transmitter requires a 6-point look-up table for saturation constants up to 3000
ppm
W
over the temperature range 0 to +50°C (+32 to +122°F). Saturation constants
for 8 common liquids can be programmed into the Easidew PRO I.S. via the Application
Software. Alternatively, the user can program saturation constants manually. The
Application Software Help fi le provides detailed instructions on how to perform this task.
3.2 Sampling Hints
Operation is very simple, assuming the following installation techniques are adhered to:
Be Sure the Sample is Representative of the Gas Under Test:
The sample point should be as close to the critical measurement point as possible. Also,
never sample from the bottom of a pipe as entrained liquids may be drawn into the
sensing element.