CHAPTER 4 APPLIED OPERATIO N
E5EK
4--6
The limiters are invalid or cannot be set when any of the following
conditions occurs:
• During ON/OFF control
• During ST execution
• During AT execution (only by MV change rate limiter)
• During manual operation
• When operation is stopped
• When an error has occurred.
• During position-proportional control (manipulated variable limiter
only)
The setting range of the set point is limited by the set point limiter. The
upper-and lower-limit values of this set point limiter are set in the “Set
point upper limit” and “Set point lower limit” parameters (expansion
mode), respectively. However, note that when the set point limiter is
reset, the set point is forcibly changed to the upper-or lower-limit value
of the set point limiter if the set point is out of the limiter range. Also,
when the input type, temperature unit and scaling (sensor) range are
changed, set point limiter is forcibly reset to the scaling (sensor) range.
Scaling (sensor) upper-and lower-limit values
Changed to
the new up-
per limit
value
Scaling (sensor) range
SP
Set point Upper-and lower-limit values of the limiter
Set point limiter
Setting range
Changed to upper
limit value
Input type changed
SP
A
○
B
×
CB
○
With the SP ramp function, the controller operates according to the val-
ue (set point during SP ramp) limited by a change rate, instead of the
changed set point when set point is changed. The interval in which the
set point during SP ramp is limited is referred to as the “SP ramp”.
SP
Set point
SP ramp
SP ramp set
value
SP ramp time u n it
Time
Switching point
F Limiter operation
conditions
JSet point limiter
JSP ramp