DH Instruments PPCK PLUS, Руководство по эксплуатации и обслуживанию

Страница: 65 / 150

PPCK+™ Operation and Maintenance Manual
Page 57
©2001 DH Instruments, Inc .
Select the desired internal function.
Select <2Cal> to view and edit calibration coefficients for the PPCK+ RPT ranges and
on-board barometer (see Section 3.4.4.2).
Select <3Remote> to view and edit RS232 (COM) port and IEEE-488 interface settings
(see Section 3.4.4.3).
Select <4Time> to adjust the date and time (see Section 3.4.4.4).
Select <5Reset> to access various system reset functions (see Section 3.4.4.5).
Select <6Level> to set the user protection level and password (see Section 3.4.4.6).
Select <7Atm> to view the on-board barometer reading (see Section 3.4.4.7).
Select <9ScrSav> to adjust the activation time of the front panel display saver (see
Section 3.4.4.8).
3.4.4.1 CONFIG

PURPOSE
To run an automated routine that determines the volume of the system into which
PPCK+ is controlling pressure to optimize the performance of thermal pressure
control (TPC) used in dynamic control mode.

PRINCIPLE
PPCK+ uses thermal pressure control (TPC) for very fine pressure control
around the target value in dynamic control mode (see Section 3.1.2.3).
For optimal TPC operation, PPCK+ must have a good estimation of the size of
the volume connected to the PPCK+ TEST port. In normal dynamic control
mode operation, if PPCK+’s estimation of the volume seems incorrect as
evidenced by unexpected control response, PPCK+ runs a 0.5 to 2.5 minute
routine to determine the test volume. The volume determination routine can also
be initiated by the operator using
[SPECIAL], 4Internal, 1Config .
The operator initiated volume determination routine can be useful after a test
volume change to avoid the increased control time and reduced control precision
that may exist until PPCK+ automatically determines the volume.
Thermal pressure control (TPC) is only used in dynamic control mode.
Therefore, the volume configuration routine only executes when dynamic control
mode is active.
Due to the high compressibility of low pressure gas, the configuration routine
does not produce reliable results at when run at a starting pressure under
1 MPa (150 psi). Therefore, the volume configuration routine cannot be run under
1 MPa (150 psi).