Mitsubishi Electric 800 Series Instruction Manual page 397

5.11.6 PID control
Process control such as flow rate, air volume or pressure are possible on the inverter.
A feedback system can be configured and PID control can be performed using the terminal 2 input signal or parameter setting
value as the set point, and the terminal 4 input signal as the feedback value.
Pr.
127 PID control automatic
A612 switchover frequency
128 PID action selection
A610
129 PID proportional band
A613
130 PID integral time
A614
131 PID upper limit
A601
132 PID lower limit
A602
133 PID action set point
A611
134 PID differential time
A615
553 PID deviation limit
A603
554 PID signal operation
A604 selection
575 Output interruption
A621 detection time
576 Output interruption
detection level
A622
577 Output interruption cancel
A623 level
396
5. PARAMETERS
5.11 (A) Application parameters
Name Initial value
9999
0
100%
1 s
9999
9999
9999
9999
9999
0
1 s
0 Hz
1000%
Setting range
0 to 590 Hz Set the value at which control is automatically switched to
PID control.
9999 Without PID control automatic switchover function
0, 10, 11, 20, 21, Select how to input the deviation value, measured value and
50, 51, 60, 61, 70, set point, and forward and reverse action.
71, 80, 81, 90, 91,
100, 101, 1000,
1001, 1010, 1011,
2000, 2001, 2010,
2011
0.1 to 1000% If a narrow proportional band is set (small parameter setting
value), the manipulated amount changes considerably by
slight changes in the measured value. As a result, response
improves as the proportional band becomes narrower,
though stability worsens as shown by the occurrence of
hunting. Gain Kp=1/proportional band
9999 Without proportional band
0.1 to 3600 s With deviation step input, this is the time (Ti) used for
obtaining the same manipulated amount as proportional
band (P) by only integral (I) action. Arrival to the set point
becomes quicker the shorter an integral time is set, though
hunting is more likely to occur.
9999 Without integral control
0 to 100% Sets the upper limit. The FUP signal is output when the
feedback value exceeds this setting. The maximum input (20
mA/5 V/10 V) of the measured value (terminal 4) is
equivalent to 100%.
9999 No function
0 to 100% Set the lower limit. The FDN signal is output when the
measured value falls below the setting range. The maximum
input (20 mA/5 V/10 V) of the measured value (terminal 4) is
equivalent to 100%.
9999 No function
0 to 100% Set the set point during PID control.
9999 Set point set by Pr.128.
0.01 to 10 s With deviation ramp input, this is the time (Td) used for
obtaining the manipulated amount only by proportional
action (P). Response to changes in deviation increase
greatly as the differential time increases.
9999 Without differential control
0 to 100% The Y48 signal is output when the absolute value of the
deviation exceeds the deviation limit value.
9999 No function
0 to 7, 10 to 17 The action when the upper or lower limit for a measured
value input is detected or when a limit for the deviation is
detected can be selected. The operation for PID output
suspension function can be selected.
0 to 3600 s If the status where the output frequency after PID calculation
is less than the Pr.576 setting is continuously the Pr.575 set
time or more, inverter running is suspended.
9999 Without output interruption function
0 to 590 Hz Set the frequency at which output interruption is performed.
900 to 1100% Level at which the PID output suspension function is
released.
Set "Pr.577 -1000%".
Description