Mitsubishi Electric MELSEC iQ-R Series - Page 1254

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11 PROCESS CONTROL INSTRUCTIONS
11.3 Control Operation Instructions
■PID operation (4)
The PID operation is performed with the following operational expression.
K
P
: K  Gain (P), M
D
: Derivative gain (MTD), T
I
: Integral constant (I), T
D
: Derivative constant (D)
Note that special processing is performed in the following cases.
■Deviation check (5)
A deviation is checked under the following conditions, and the result is output to the DVLA of the alarm detection (ALM) and
the large deviation alarm (BB2).
*1 If the DMLI or ERRI of the disable alarm detection (INH) is set to 1, the DVLA of the alarm detection (ALM) and the large deviation alarm
(BB2) are set to 0.
■Mode determination (6)
The following processing is performed depending on the control mode (MODE).
Item Operational expression
B
n
Direct action (PN = 1)
Reserve action (PN =
0)
I
n
TK
p
 (DV
n
+ I
n
+ B
n
)
Condition Processing
In either of the following cases:
1. Derivative constant (D) = 0 (T
D
= 0)
2. Control mode (MODE) = MAN, LCM, or CMV
B
n
= 0
(Note that the loop tag past value memory is set.)
In any of the following cases:
1. Integral constant (I) = 0 (T
I
= 0)
2. MHA2 of the alarm detection 2 (ALM2) = 1
3. MLA2 of the alarm detection 2 (ALM2) = 1
4. Control mode (MODE) = MAN, LCM, or CMV
When all of the following conditions are satisfied:
1. b0 of SD818 (bumpless switching function of S.PIDP control) = 1.
2. TRKF of the disable alarm detection (INH) = 1
3. Control mode (MODE) = Other than MAN, LCM, and CMV
TRKF = 0
Condition Result
DVL < |DV| DVLA = BB2 = 1
*1
(DVL - DVLS) < |DV|  DVL DVLA = BB2 = Last value
*1
|DV|  (DVL - DVLS) DVLA = BB2 = 0
Control mode (MODE) Processing details
MAN, CMB, CMV, LCM
(alarm clear processing)
• The MHA, MLA, and DMLA of the alarm detection (ALM) are set to 0.
• The MHA2 and MLA2 of the alarm detection 2 (ALM2) are set to 0.
• The alarm bits (BB3, BB4, and BB5) are set to 0.
• The data of BB2 is transferred to BB1. (BB1 = BB2)
• When b0 of SD818 (bumpless switching function of S.PIDP control) is 1, TRKF of INH is set to 1.
• "Output conversion processing (8)" is performed and the instruction ends.
AUT, CAB, CAS, CCB, CSV, LCA, LCC "Variation rate & upper/lower limiter processing (7)" is performed.
B
n-1
+
×{(PV
n
-
PV
n-1
)-
}
M
D
×CT+T
D
M
D
×T
D
T
D
CT×B
n-1
B
n-1
+
×{-(PV-PV
n-1
)-
}
M
D
×CT+T
D
M
D
×T
D
T
D
CT×B
n-1
×DV
n
I
n-1
+
T
I
CT
×DV
n
>0
T
I
CT
×DV
n
<0
T
I
CT
×DV
n
=0
T
I
CT
I
n-1
=
K
p
MV
-(DV
n
+B
n
)