GE PM880, Руководство пользователя

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Chapter 4. Using Special Features
66 Model PM880 Portable Hygrometer User’s Manual
4.9 Using Computer Enhanced Response
Computer Enhanced Response (CER) uses a dynamic moisture calibration
technique to extrapolate the moisture level to the end point when making
measurements in abrupt “dry down” conditions. The system response time
depends on the relative change in dewpoint. For a change from ambient
moisture levels to trace levels, the unit can respond in 3 to 5 minutes.
The accuracy of enhanced response is ±2
o
C of the reading the sensor would
have read if it were allowed to reach equilibrium with the gas. To ensure
that CER is as accurate as possible, your application should:
•
have a reasonably constant final dewpoint and flow rate.
•
have a minimum flow rate of one standard cubic foot per hour
(SCFH).
•
operate at atmospheric pressure (0 psig).
•
have an actual moisture content equal to or wetter than a dew/frost
point of
•
MIS Probe: –85
o
C
•
M Series and TF Series Probe: –110
o
C
Use the steps below to activate computer enhanced response:
4.9.0a Accessing the Response Command
1.
If the menu is not active, press
[MENU]
.
2.
Use the arrow key to scroll to
Program
and press [ENTER] .
3.
Use the arrow key to scroll to System and press
[ENTER]
. A screen
similar to Figure 29 on page 67 appears.