PPC3™ OPERATION AND MAINTENANCE MANUAL
© 2002-2007 DH Instruments, a Fluke Company Page 20
During dynamic pressure control, the hold limit is active. If the pressure goes outside of the
hold limit, a Not Ready condition occurs. See Tables 6 and 7 for default hold limit values and
Section 3.3.6 to customize the hold limit.
Figure 6. Dynamic Pressure Control Operation
Static Control
Static control mode is designed to set the pressure near the target value and then interrupt
active control to allow pressure to stabilize naturally within the hold limit. The advantage of
this control mode is that pressure can be set and/or measured within a defined limit of a
target without interference from the pressure control system. In a system without excessive
leaks, the pressure stability achieved may be greater than the stability with which the
pressure control system can actively control pressure. Using static control to control
pressure near the desired set point and then measuring back the stabilized pressure without
interference of the control function can allow control errors to be completely eliminated.
However, the final pressure achieved is not equal to the target value.
During static pressure control, the hold limit is active. If the pressure goes outside of the hold limit,
a Not Ready condition occurs (see Section 3.2.2) and pressure is readjusted to the target value
(see Tables 6 and 7 and Section 3.3.6 for setting the hold and stability limits to user defined values).
Figure 7. Static Pressure Control Operation
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