User manual VAISALA DM500

[. . . ] USER'S GUIDE Vaisala DEWCAP Precision SAW Hygrometer DM500 ® M210205EN-D PUBLISHED BY Vaisala Oyj P. O. Box 26 FIN-00421 Helsinki Finland Phone (int. ): +358 9 8949 1 Fax: +358 9 8949 2227 Visit our Internet pages at http://www. vaisala. com/ © Vaisala 2006 No part of this manual may be reproduced in any form or by any means, electronic or mechanical (including photocopying), nor may its contents be communicated to a third party without prior written permission of the copyright holder. The contents are subject to change without prior notice. Please observe that this manual does not create any legally binding obligations for Vaisala towards the customer or end user. All legally binding commitments and agreements are included exclusively in the applicable supply contract or Conditions of Sale. ________________________________________________________________________________ Table of Contents CHAPTER 1 GENERAL INFORMATION. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . [. . . ] To set the scaling manually, select with the arrow button the Min and Max values and change the values by using the numerical buttons. If you set manually impossible values (for example min > max), the automatic scaling is forced to the on state. Press BACK and EXIT to return to the main view. All the individual Hold/Save data points are saved in the same file until the power is switched off. When switching on again and saving data, the data points are saved in a different data file. Graphic Trend Graphic trend shows you the data curve from the time turning on the device. Open MENU: press . Select Display, press Select Graphic trend, press SHOW. VAISALA _______________________________________________________________________ 55 User's Guide ______________________________________________________________________ 4. 6. Press Press Press NEXT to see the graphic trend of the other parameters. OPTIONS to set the following graph options Show value: Select YES to have the data shown numerically. To set the scaling manually, select with the arrow button the Min and Max values and change the values by using the numerical buttons. If you set manually impossible values (for example min > max ), the automatic scaling is forced to the on state. Hide function keys: Select 7. To zoom in the curve, press the arrow button . To select the individual data points from the curve, press either of the buttons . Press MAIN VIEW to return to the main view. 8. Contrast Adjustment You can change the contrast of the LCD display using the Contrast adjustment. 1. LIGHT. Select Display, press Select Contrast adjustment, press To increase the contrast, press To decrease the contrast, press Press OK and EXIT to return to the main view. Alarm Sound DM500 alarms by beeping and blinking the display. The alarm function can be enabled also on the basis of the measurement status. If there are no set points selected, measurement status controls the alarm. 56 __________________________________________________________________ M210205EN-D Chapter 10 __________________________________________________________ Display Settings 1. . SET , select the quantity for the alarm and Select Display, press Select Alert above, press SET. (In case you want to delete the setpoint, press DELETE and go to item 6). (In case you want to delete the setpoint, press DELETE and go to item 8). Now you can select the measurement status that activates the alarm. STOP: alarm is enabled when dewpoint measuring status is STOP. OK: alarm is enabled when dewpoint measuring status is OK WAIT: alarm is enabled when dewpoint measuring status is WAIT All the modes selected: alarming is not dependent on any measurement status (only on numeric set points). You can select any combination of the measurement status to control the alarm. Press OK and EXIT to return to the main view. Alarming The display is beeping and blinking and the note sign message is shown in the display. [. . . ] Dalton's law states that in a gas mixture, such as air, the total pressure of the gas is the sum of the partial pressures of each of the component gases Ptotal = Pnitrogen + Poxygen + Pwater + Pothers (1) Thus, atmospheric pressure is actually the sum of the partial pressures of nitrogen, oxygen, water vapor, carbon dioxide, and small amounts of other gases. VAISALA ______________________________________________________________________ 127 User's Guide ______________________________________________________________________ There are many ways of expressing the water vapor content of a gas. Some water vapor quantities, such as dewpoint temperature, can be measured directly and fundamentally. Other parameters, such as relative humidity, require knowledge of additional information, such as the temperature of the gas. Saturation Vapor Pressure Saturation vapor pressure is the maximum pressure of water vapor that can exist at a given temperature. This quantity is expressed in pressure units such as Pascals or millibars, and is often represented by the symbol "e. " There is a unique saturation vapor pressure for any temperature. [. . . ]