CHAPTER 4 APPLIED OPERATION
E5CK
4–6
The limitters are disabled or cannot be set when any of the following
conditions occurs:
Ă• During ON/OFF control
Ă• During AT execution (only by MV change rate limitter)
Ă• During manual operation
Ă• When operation is stopped
Ă• When an error has occurred
The setting range of the set point is limited by the set point limitter. The
upperĆ and lowerĆlimit values of this set point limitter are set in the set
point upper limit" and set point lower limit" parameters (expansion
mode), respectively. However, note that when the set point limitter is reset,
the set point is forcibly changed to the upperĆ or lowerĆlimit value of the
set point limitter if the set point is out of the limitter range. Also, when the
input type, temperature unit and scaling (sensor) range are changed, the
set point limitter is forcibly reset to the scaling (sensor) range.
Scaling (sensor) upper-and lower-limitter values
Changed to
the new up-
per limit
value
Scaling (sensor) range
Set Point
Set point Upper-and lower-limit values of the limitter
Set point limiter
Setting range
Changed to upper
limit value
Input type changed
Set Point
A
Ę
B
CB
Ę
(setting impossible)
(setting possible)
C
Set Point
Symbol
Parameter Name: Mode Description
MV upper limit : Level 2 For limiting manipulated variable
MV lower limit : Level 2 For limiting manipulated variable
MV change rate limit : Level 2 For limiting manipulated variable
Set point upper limit : Expansion For limiting SP setting
Set point lower limit : Expansion For limiting SP setting
Control output 1
assignment : Setup
For specifying control method
Control output 2
assignment : Setup
For specifying control method
Direct/reverse
operation : Setup
For specifying control method
Dead band : Level 1 Heating and cooling control
Cooling coefficient : Level 1 Heating and cooling control
MV at reset : Level 2 Manipulated variable when con-
trol operation is stopped
MV at PV error : Level 2 Manipulated variable when con-
trol operation is PV error
Hysteresis (heat) : Level 1 ON/OFF control
Hysteresis (cool) : Level 1 ON/OFF control
PID / ON/OFF : Expansion ON/OFF control
F Limiter operation
conditions
JSet point limiter
Parameters
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