3. OPERATION
Page 27
© 2007 DH Instruments, a Fluke Company
Figure 11.
Monotonic pressure control operation
PPCH-G includes a
Ready/Not Ready
feature that indicates when current
pressure control requirements have been met (see Section 3.2.3).
With monotonic pressure control active, a
Ready
condition occurs whenever:
•
PPCH-G has reached the pressure target limit, and;
•
is controlling ramp rate at less than the pressure rate limit.
Figure 12 illustrates
Ready/Not Ready
operation in monotonic control mode.
Figure 12.
Ready/Not Ready
in monotonic pressure control mode
3.2.2.5
RAMP CONTROL
Ramp control
is designed to set a pressure ramp at a target rate and maintain
the rate within a rate hold limit (see Figure 13). This control mode can be used
for a variety of calibration and testing functions.
When setting a ramp, PPCH-G attempts to establish the target rate within the rate
hold limit and then maintains the rate until a new command is given or the active
pressure range “upper limit” is reached (see Section 3.4.4). If the rate is outside of
the rate hold limit, a
Not Ready
condition occurs. See Table 8 for default target rate
and hold limit values and Section 3.4.6 to customize the hold limit.
