West Control Solutions ProVU 4 - Manual (Page 154)

ProVU4 Controller, Profiler & Recorder/Controller - Product Manual
59407, Issue 1 – March 2008 Glossary Page 153
Profiler
A profiler controls the value of the actual setpoint over time; increasing, decreasing or
holding its value as required. This is used in applications where the rate of rise or fall of the
process variable must be closely controlled, or where a value must be maintained for a
period before moving to the next value.
If the Profiler option is fitted, up to 64 profiles can be created with a maximum of 255 profile
segments shared amongst them. Each segment can have up to five events active.
Refer to the Profiler Option section.
Also refer to: Actual Setpoint, Controller Mode, Profile Events, Profile Control Menu, Profile
Header, Profile Segments, Profile Setup Menu and Profiler Mode.
Profiler Mode
This mode is entered when a profile is run. In profiler mode, additional screens are added to
Operation Mode which show the status of the profile. These screens are not seen in
Controller Mode. The instrument will remain in Profiler Mode when the profile finishes or is
aborted unless the Segment End Type/Profile Abort Action is set to “Use Controller Setpoint”.
Also refer to: Controller Mode, Profile Control Menu, Profile Segments, Profile Setup Menu,
Profiler and Setpoint.
Proportional Control
Proportional control allows the correcting variable applied to the process to be set between 0
and 100% of the amount available. If the control type is dual, two outputs (primary &
secondary) are available, each of which can give proportional control. When the Proportional
Band(s) are correctly tuned, the process variable is maintained at a steady value, avoiding
the oscillation characteristic of On-Off control. Proportional control is most commonly used in
conjunction with Integral and Derivative action to give PI. PD or PID control.
Also refer to: Control Type, Correcting Variable, Derivative Action, Integral Action, On-Off
Control, PD, PI, PID, Primary Proportional Band, Process Variable, Secondary Proportional
Band, Setpoint and Tuning.
Rate
- Refer to Derivative Action.
Rate Of Change Alarm
An alarm based on the rate of change in the measured process variable. If the PV changes
at a rate greater than the alarm level, the alarm will activate. The rate of change must be
above the alarm threshold for longer than the Minimum Duration Of Change time, before the
alarm will change state (from on to off, or off to on).
Caution: If the duration is less than this
time, the alarm will not activate no matter how fast the rate of rise.
Also refer to: Alarm Hysteresis, Alarm Operation, Alarm Types, Minimum Duration Of
Change and Process Variable.
Recorder Configuration
If the Data Recorder is fitted, a Recorder Configuration sub-menu is added to Configuration
Mode. This is used to adjust the recorder parameters (Recording mode, sample interval,
trigger and values to record) and to show the recorder status.
Also refer to: Configuration Mode, and Data Recorder