Mitsubishi Electric MELSEC iQ-R Series Programming Manual page 1238

Processing details
This instruction performs PID operation when the specified control cycle is reached. (The PID operation is of the velocity type/
process value differential type (inexact differential).)
At this time, the instruction also performs the following processing steps: SV setting, tracking, gain (Kp) operation, and
deviation check.
The following is the processing block diagram of the S.PID instruction. (The numbers (1) to (7) in the diagram indicate the
order of the processing.)
RL, RH
E1
(1)
E2
SV setting
(When used)
CT
(6)
SPA
MODE
ERRI¸DVLI
DVLA
■SV setting processing (1)
The following processing is performed depending on the control mode (MODE) setting.
Control mode (MODE) setting
CAS, CCB, CSV
MAN, AUT, CMV, CMB, CAB, LCM, LCA, LCC
■Tracking processing (2)
• The set value (SV) is inversely transformed from the engineering value and SV
expression).
100
SV '= ×(SV -RL)
n
n
RH-RL
• Tracking processing is performed when all of the following conditions are satisfied.
• The tracking bit (TRK) is set to 1.
• The set value (E2) is used.
• The control mode (MODE) is set to any of the following: MAN, AUT, CMV, CMB, CAB, LCM, LCA, or LCC.
E2 = SV '
n
• If the set value (E2) is the upper loop MV, the TRKF of the disable alarm detection (INH) of the upper loop is set to 1.
11 PROCESS CONTROL INSTRUCTIONS
1236
11.3 Control Operation Instructions
(2)
Tracking
(7)
Control cycle
determination
RUN (SPA=0)
STOP (SPA=1)
Loop stop
determination
(6)
MAN
GW,
DV P, I, D, MTD, CT
GG
(3) (4)
Gain (Kp)
operation PID operation
processing
Reached
Not reached
BW=0
Loop stop
OFF OFF
processing
Processing details
• If the set value (E2) is specified, engineering value transformation processing (refer to the
following expression) is performed, and then "tracking processing (2)" is performed.
RH-RL
SV = ×E2+RL
n
100
• If the set value (E2) is not specified, "tracking processing (2)" is performed without
performing engineering value transformation processing.
"Tracking processing (2)" is performed.
DVL, DVLS
(5)
Deviation
check
AND
BW=0
' is calculated (refer to the following
n
BW
BB1