Mitsubishi Electric MELSEC iQ-R Series - Page 1238

1236
11 PROCESS CONTROL INSTRUCTIONS
11.3 Control Operation Instructions
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.)
■SV setting processing (1)
The following processing is performed depending on the control mode (MODE) setting.
■Tracking processing (2)
• The set value (SV) is inversely transformed from the engineering value and SV
n
' is calculated (refer to the following
expression).
• Tracking processing is performed when all of the following conditions are satisfied.
• 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.
Control mode (MODE) setting Processing details
CAS, CCB, CSV • 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.
• If the set value (E2) is not specified, "tracking processing (2)" is performed without
performing engineering value transformation processing.
MAN, AUT, CMV, CMB, CAB, LCM, LCA, LCC "Tracking processing (2)" is performed.
• 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
'
E2
BW
MAN
MODE
SPA
CT
E1
AND
DVLA
ERRI¸DVLI
BW=0
BW=0
BB1
(1) (2) (3) (4) (5)
OFF
(6)
(6)
(7)
OFF
Loop stop
processing
DV
RL, RH
DVL, DVLS
P, I, D, MTD, CT
GW,
GG
(When used)
SV setting
Tracking
Gain (Kp)
operation
processing
PID operation
Deviation
check
Control cycle
determination
Reached
Not reached
Loop stop
determination
STOP (SPA=1)
RUN (SPA=0)
SV
n
= ×E2+RL
100
RH-RL
SV
n
'=
×(SV
n
-RL)
RH-RL
100