Micromod MOD: 1800P - MOD 30ML Identity Module (Version 2) PID and Ramp/Soak Functions - Manual (Page 43)

Continuous Control Functions
RAMP SOAK BLOCK
3-3
3.2 RAMP/SOAK BLOCK OPERATION
Figure 3-1 shows the characteristics of a Ramp/Soak profile. Explanations of the profile
characteristics follow. Initial values are written to this block when it is initially downloaded.
They may be overwritten when this block executes.
PROFILE STARTUP
Segment 1 may start with a Step, a Soak or a Ramp as follows:
•
Segment 1 starts as a step segment if the time interval for segment 1 is 0.
•
Segment starts as a soak segment if the Start Value is equal to the Target Value of
segment 1. The desired Result is the segment 1 Target Value.
•
Segment 1 starts as a ramp segment and the ramp rate is calculated using the Start
Value, segment 1 Target Value and segment 1 Time. This ramp rate is used when the
profile starts if the first segment is a ramp regardless of the Startup Type parameter.
If the first segment is a ramp segment the desired Result will be determined by the Startup
Type parameter as follows:
•
START VALUE: The desired Result will be set to the Start Value.
•
TRACK VALUE: The desired Result will be set to the Track Input Value.
•
PROCESS VALUE: The desired Result will be set to the Process Input Value.
If Segment 1 Guaranteed is set to NO the profile Result will be set to the desired Result and
the profile is running.
If Segment 1 Guaranteed is set to YES the profile Result will remain unchanged (profile not
running) until the Process Input value is within the appropriate hysteresis value of the value
determined by the Startup Type parameter.
GUARANTEED RAMP
During a guaranteed ramp segment (GTSn), the Process Input value (PROCINP) is compared
with the Result value (R). If the Process Input value is not equal to the Result plus or minus
the Ramp Hysteresis value (RHYST) the ramping of the Result value will stop and the Time
Remaining (TREM) will not change. Therefore, the time for a ramp segment to get to the
Target Value (TVSn) may be longer than the configured Time Interval (TISn) for the segment.
GUARANTEED STEP
For a guaranteed step segment (GTSn) the step change to the Result (R) will not occur until
the Process Input value (PROCINP) is equal to the Result value (R) plus or minus the Ramp
Hysteresis value (RHYST).
GUARANTEED SOAK
During a guaranteed soak segment (GTSn) the Process Input value (PROCINP) is compared
with the Result value (R) and if the Process Input value is not equal to the Result plus or
minus the Soak Hysteresis value (SHYST) the Time Remaining (TREM) will not change.
Therefore, the time for a soak segment may be longer than the configured Time Interval
(TISn) for the segment.