145
PARAMETERS
4
(5) Parameter setting
(6) Adjustment procedure
Parameter
Number
Setting Name Description
128
10
PID action
selection
For heating, pressure control, etc.
Deviation value
signal input(terminal
1)
PID reverse
action
11 For cooling, etc.
PID forward
action
20 For heating, pressure control, etc.
Set point (No.2
terminal or Pr. 133),
measured value input
(No.4 terminal)
PID reverse
action
21 For cooling, etc.
PID forward
action
129
0.1 to 1000%
PID proportional
band
If the proportional band is narrow (parameter setting is small), the
manipulated variable varies greatly with a slight change of the process value.
Hence, as the proportional band narrows, the response sensitivity (gain)
improves but the stability deteriorates, e.g. hunting occurs.
Gain K = 1/proportional band
9999 No proportional control
130
0.1 to 3600 s
PID integral time
Time required for the integral (I) action to provide the same manipulated
variable as that for the proportional (P) action. As the integral time decreases,
the set point is reached earlier but hunting occurs more easily.
9999 No integral control.
131
0 to 100%
Upper limit
Set the upper limit. If the feedback value exceeds the setting, the FUP signal
is output. (Process value of 4mA is equivalent to 0% and 20mA to 100%.)
9999 No function
132
0 to 100%
Lower limit
Set the lower limit. (If the process value did not reach the setting range, an
alarm can be output. In this case, the process value of 4mA is equivalent to
0% and 20mA to 100%.)
9999 No function
133 0 to 100%
PID action set
point for PU
operation
Only valid for the PU command in the PU operation or PU/external combined
mode.
For external operation, the voltage across 2-5 is the set point.
(Pr. 902 value is equivalent to 0% and Pr. 903 value to 100%.)
134
0.01 to 10.00 s
PID differential
time
Time only required for the differential (D) action to provide the same process
value as that for the proportional (P) action. As the differential time increases,
greater response is made to a deviation change.
9999 No differential control.
Set the I/O terminals for PID control.
(Pr. 180 to Pr. 186, Pr. 190 to Pr. 195)
Pr. 128 = 10, 11, 20, 21
Parameter setting
Terminal setting
Switch X14 signal on.
Run
Adjust the PID control parameters, Pr. 128 to Pr. 134.
