Mitsubishi MELSEC-Q series Programming Manual page 253

(9) Response waveform observation processing
The following processing is performed for the input value (E1).
(a) Response waveform observation
1) The counter from auto tuning start is incremented.
2) The following processing is performed according to the input value (E1) and last process value (PV
Reverse operation (PN = 0)
Forward operation (PN = 1)
3) The input value (E1) is stored into the last process value (PV
(b) Maximum slope value
Depending on the slope (T2), the following processing is performed and the S. AT1 instruction is terminated.
1) If reverse operation is performed (PN = 0) and AT1 stepped manipulated value (AT1STEPMV)  0 or forward
operation is performed (PN = 1) and AT1 stepped manipulated value (AT1STEPMV) < 0
Condition
Maximum slope value slope  (T2)
Maximum slope value > Slope(T2) Maximum slope value remains unchanged from the last value.
2) If forward operation is performed (PN = 1) and AT1 stepped manipulated value (AT1STEPMV)  0 or reverse
operation is performed (PN = 0) and AT1 stepped manipulated value (AT1STEPMV) = 0
Condition
Maximum slope value  Slope(T2)
Maximum slope value < Slope(T2) Maximum slope value remains unchanged from the last value.
(10) Identification processing
Using the maximum slope value, the following processing is performed.
(a) Response speed
1) The response speed for calculation (R') and response speed (R) are calculated with the following expression.
Maximum
slope value(%)
R'
AT1ST(s)
2) If R = 0, the following processing is performed and the S. AT1 instruction is terminated.
The identification alarm (BB8) is turned to 1.
The auto tuning completed (BB16) is turned to 1.
When the stepped manipulated value preset flag is 1, the following processing is performed.
MV = MV - AT1STEPMV
(b) Equivalent dead time
1) The segment (b) made by the Y axis and the equivalent dead time (L) provided when the tangent line is drawn at
the response speed for calculation (R') are calculated with the following expression.
b = (maximum slope-time PV) - R' × (maximum slope counter) × AT1ST
(Auto tuning start-time PV0)-b
L
2) If L  0, the following processing is performed and the S. AT1 instruction is terminated.
The identification alarm (BB8) is turned to 1.
The auto tuning completed (BB16) is turned to 1.
When the stepped manipulated value preset flag is 1, the following processing is performed.
MV = MV - AT1STEPMV
T2 = E1 - PV
n-1
• Maximum slope value = slope (T2)
• Maximum slope-time counter = counter from auto tuning start
• Maximum slope-time PV = input value (E1)
• After maximum slope time-out count value is reset and count is restarted.
• Maximum slope value = slope (T2)
• Maximum slope-time counter = counter from auto tuning start
• Maximum slope-time PV = input value (E1)
• After maximum slope time-out count value is reset and count is restarted.
|R'|
,
R (/s)
100
R'
).
n-1
Processing
Processing
S. AT1
1
).
n-1
2
3
4
13
6
7
8
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