PPC2 AF OPERATION AND MAINTENANCE MANUAL
© 1998 DH Instruments, Inc. Page 22
3.1.2.4.2 Dynamic Control Ready/Not Ready
When dynamic pressure control mode is active a "ready" condition will occur when:
1. The current measured pressure is inside the hold limit.
Ready/Not Ready in Dynamic Pressure Control Mode
3.1.2.4.3 Ready/Not Ready When Automated Pressure
Control is Not Active
When no automated pressure control is active, "ready" is indicated whenever the
rate of change of pressure is less than the current stability limit.
3.1.2.5 MULTIPLE PRESSURE RANGES
PPC2 AF has two reference pressure transducers each of which has three
ranges for a total of six pressure ranges. This multiranging feature allows
accuracy to be optimized for the range of pressure in which you are working.
Generally, the best range to select (see Section 3.2.1) is that whose full scale is
closest to, but not less than, the maximum pressure at which you need to work.
PPC2 AF handles all of the data and internal valving operations needed to make
range changes occur transparently to the operator when the RANGE function is
used to select a range. Ranges available can be viewed at any time but changing
ranges can only occur when PPC2 AF is vented.
When ranges are changed, the upper limit is automatically changed to the default
for that range or to the last upper limit that was set for that range (see Section 3.2.4).
In addition, most other functions are range specific (see Section 3.2.1 below).
PPC2 AF has six ranges on two transducers. In general, user settings and
operational adjustments are specific to the range currently in use, as if you
had six instruments rather than one.
The PPC2 AF internal valving for handling of the two reference transducers is:
Valving – Hi and Lo Reference Transducers
To Next Page
Loading...