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Using the SP Ramp Function to Limit the SP Change Rate Section 4-7
Setting the Set Point Lower-limit Value
Operating Procedure Set Point Lower Limit = −100
4-7 Using the SP Ramp Function to Limit the SP Change Rate
4-7-1 SP Ramp
The SP ramp function is used to restrict the width of changes in the set point
as a rate of change. When the SP ramp function is enabled and the change
width exceeds the specified rate of change, an area where the set point is
restricted will be created, as shown in the following diagram.
During the SP ramp, control will be performed not for the specified set point
but rather for the set point restricted by the rate of change set for the SP ramp
function.
The rate of change during SP ramp is specified using the SP Ramp Set Value
and SP Ramp Time Unit parameters. The SP Ramp Set Value parameter is
set to OFF by default, i.e., the SP ramp function is disabled.
Changes in the ramp set point can be monitored in the Set Point During SP
Ramp parameter (operation level). Use this parameter when monitoring SP
ramp operation.
The SP ramp function operates in the same way when switching the set point
using the multi-SP function.
Parameters
1. Select the Set Point Lower Limit parameter in the initial setting level.
2. Use the U and D Keys to set the parameter to
−100.
C
sl-l
-200
Set Point
Lower Limit
C
sl-l
-100
SP
SP ramp
SP after change
SP before change
Point of chan
e
Time
SP ramp
set value
SP ramp time unit (s/min)
Symbol Parameter: level Description
ol-h
ol-l
sl-h
sl-l
sprt
spru
alsp
MV Upper Limit: Adjustment level
MV Lower Limit: Adjustment level
Set Point Upper Limit: Initial setting level
Set Point Lower Limit: Initial setting level
SP Ramp Set Value: Adjustment level
SP Ramp Time Unit: Advanced function setting level
Alarm SP Selection: Advanced function setting level
To limit the manipulated variable
To limit the manipulated variable
To limit the SP setting
To limit the SP setting
To limit the SP rate of change
Unit for setting the SP
Alarm SP selection