Ashcroft ATE-100 Handheld LCD Digital Calibrator - Manual (Page 22)

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Revision 4.6 3/2004
Step 2 To exit the hold function press any key.
Note: While in the hold mode, if the RS232 interface is
enabled, the HHC will continue to transmit the displayed
values.
Section 11.0 Minimum and Maximum Value
Tracking
The HHC monitors and stores in memory both the
minimum and maximum pressure or temperature values
measured. The following procedure will allow review of
these values.
Step 1 To recall the minimum and maximum values
simply press the key labeled:
MIN
MAX
The HHC will respond by displaying:
+2345 +12345
-12345 -12345
where: maximum values are displayed on the top line
and +12345 represents the maximum value(s) measured.
Minimum values are displayed on the bottom line and
12345 represents the minimum value(s) measured.
If two Quick Select modules are installed, the min/max
function recalls and displays the minimum and maxi-
mum values for both modules simultaneously.
Step 2 To clear the stored minimum and maximum
value press the clear entry key:
CE
Pressing any key other than the CE key will maintain the
stored values in memory.
Pressing any key on the keypad will return the HHC to
normal pressure measurement activities.
Section 12.0 Damping
Damping provides the ability to stabilize the displayed
or transmitted pressure value by minimizing the effects
of low level transients and electronic instability. Damp-
ing is most commonly used with Quick Select pressure
modules to overcome the effects of pressure pulsation
and vibration transmitted through the measurement
media. The level of damping is established in the set
up menu. Activation of the damping process is accom-
plished through a dedicated key on the keypad.
Damping accomplishes the stabilization of the pressure
measurement value by producing an averaged pressure
value which is shown on the display and available for
transmission over the RS232 interface. When damping is
not activated the HHC takes a new pressure value every
130 to 240mS (~8 times per second) and updates the
display. If required, this same measurement data is also
transmitted over the RS232 interface.
When damping is activated the value displayed and/or
transmitted is an average value. The average consists
of the average of from 1-16 consecutive readings. The
higher the number of readings averaged the greater
the stabilization effect of the damping. The number of
consecutive readings averaged is programmable, allow-
ing the damping function to be tailored to the specific
requirements of most any application.
Section 12.1 Set Up of the Damping Function
The following steps should be used to set up the level of
damping desired.
Step 1 With the HHC on and reading pressure press the
SET UP key.
SET
UP
Step 2 Using the arrow keys move through the set up
menu and select “Dampen” on the display of the HHC.
The word “Dampen” will flash on the display when
selected.
EvntTimr Dampen
LeakRate Status
Step 3 With the word Dampen flashing press the
enter key.
ENT
Step 4 In response to the activation of the dampening
set up menu the HHC will respond by displaying the fol-
lowing:
fast <------- >
slow X
Where the left most position represents zero damping
(averaging of 1) and the right most position represents
maximum damping (averaging of 16 readings). Starting
from the left each movement of the highlighted box to
the right increases the number of samples being aver-
aged by one (1). By moving the highlighted field to the
left the level of damping can be reduced.
The level of damping desired will likely vary from appli-
cation to application and sensor range to sensor range.
For best results, select the minimum amount of damping
necessary to provide a stable display value. It is impor-
tant to recognize that while damping will stabilize the
displayed and/or transmitted value it will also slow down
the response rate to a true pressure change. The slow