Mitsubishi Electric FR-A520-0.4K -55K Instruction Manual page 141

( 5 ) Parameter setting
Parameter
Setting
Number
10
11
PID action
128
selection
20
21
0.1 to 1000%
PID proportional
129
band
9999
0.1 to 3600 s
130 PID integral time
9999
0 to 100%
131 Upper limit
9999
0 to 100%
132 Lower limit
9999
PID action set
133 0 to 100% point for PU
operation
134 0.01 to 10.00 s PID differential
time
9999
( 6 ) Adjustment procedure
Parameter setting
Terminal setting
Switch X14 signal on.
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Name
For heating, pressure control,
etc.
For cooling, etc.
For heating, pressure control,
etc.
For cooling, etc.
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
No proportional control
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.
No integral control.
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%.)
No function
Set the lower limit. (If the process value goes out of the setting range, an
alarm can be output. In this case, the process value of 4mA is equivalent to
0% and 20mA to 100%.)
No function
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%.)
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.
No differential control.
Adjust the PID control parameters, Pr. 128 to Pr. 133.
Set the I/O terminals and PID control terminals.
Pr. 128 = 10, 11, 20, 21
Run
128
PARAMETERS
Description
PID reverse
Deviation value
action
signal input
PID forward
(terminal 1)
action
PID reverse
action
Process value input
(terminal 4) PID forward
action