4.2 Operating Condition Restrictions
E5CK
4--5
The limiters are invalid or cannot be set when any of the following condi-
tions 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.
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 in-
put 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
×
C
B
○
With the SP ramp function, the controller operates according to the value
(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 unit
Time
Switching point
F
Limiter operation
conditions
J
Set point limiter
J
SP ramp
