Crystal DataLoggerXP Digital Pressure Gauge Software - Manual (Page 9)

Functions  7
XP2i Operation Manual
Water density (Inches of Water)
The following applies only to models where inches of water is a selectable pressure unit. As shipped from the factory, the XP2i is set to display inches of water
corresponding to the density of water at 4° C (39.2° F). You may require a different water density for your application, so the XP2i can be set to use the density
of water at 20° C (68° F) or 15.6° C (60° F) instead.
To check and/or change the water density setting from the keypad, turn on the XP2i by pressing the
(
on/off
)
button and the
(
peak
)
button simultaneously.
The display will indicate either 4C , 60F , or 68F .
Press the
(
units
)
button until the display cycles to the desired water density, then press the
(
zero
)
button to store the selection (this will not zero the gauge).
Select and set the desired density of water.
Note: If the XP2i is password protected, or inches of water is disabled, you will not be able to view or change the water density from the keypad.
overpressure conditions
The XP2i will read pressure up to approximately 110% of the rated pressure range. Above 110% percent of the range the display will start flashing and the
readings will not be reliable. The zero function does not affect the point at which the display starts flashing to indicate overpressure, so depending on the zero
value it is possible that the display can start flashing without the maximum pressure being displayed.
For instance, if a 100PSIXP2i is zeroed when 30 psi is being applied, it will indicate that the overpressure condition has been reached at 80 psi
(i.e., 110% x 100 psi – 30 psi = 80 psi).
Overpressure can affect accuracy, but the effect is only temporary unless the sensor has been destroyed. See Pressure ranges, display scales, & resolution
on page 28 for maximum overpressure.
PsVtest Mode
PSVtest mode is designed for PSV and PRV (“Pressure Safety Valve” and “Pressure Relief Valve”, respectively) as well as for Rupture Disc (also known as “Burst
Disc”) testing. It increases the measurement rate of the XP2i gauge to approximately eight times per second, to capture the peak pressure when the valve
opened, and adds a method of automatically capturing the closing reseat pressure.
Use ConfigXP to activate PSVtest Mode. When the Peak High icon (
HI
) flashes, PSVtest mode is enabled. A special feature of PSVtest is that Peak Low is au-
tomatically reset to the Peak High value whenever a new Peak High value is detected. Once pressure stops increasing, as when a PSV opens (and the pressure
drops below the maximum pressure) XP2i detects the new minimum pressure values (the Peak Low), capturing the closing pressure of a PSV.
Press the
(
peak
)
button once to view the captured reseat pressure. The Peak Low icon ( LO ) will flash on the display.
To clear the peaks, press the
(
clear
)
button while the display shows the High (
HI
) or Low ( LO ) icons.
Application note AN-006 –Pressure Safety Valve Testing detailing the operation of the PSVtest mode is available on xp2i.com , and includes examples on how to
use the gauge in relief valve and burst disk testing.