!
242
In
this case, the input data word, IR 010,
contains #0014, and f(0014) = #0726 is
output to R, IR 011.
X
Y
$1F20
$0F00
$0726
$0402
(0,0)
$0005 $0014 $001A $05F0
(x,y)
5-21-6 PID CONTROL – PID(––)
S: Input word
IR, SR, AR, DM, HR, LR,
C: First parameter word
IR, SR, DM, HR, LR
Operand Data Areas
D: Output word
IR, SR, AR, DM, HR, LR
Ladder Symbol
PID(––)
S
C
D
Limitations C and C+32 must be within the same data area.
Caution Do
not program PID(––) in the following situations. Doing so may produce unex
-
pected behavior: In interrupt programs, in subroutines, between IL(02) and
ILC(03),
between JMP(04) and JME(05), and in step programming (when using
STEP(08) and SNXT(09)).
Description PID(––)
carries out PID control according to the designated parameters. It takes
the specified input range of binary data from the contents of input word S and
carries
out the PID operation according to the parameters that are set. The re
-
sults are then stored as the operation output amount in output word D.
PID
parameter
words range from C through C+32. The PID parameters are con
-
figured as shown below.
Word 15 to 12 11 to 8 7 to 4 3 to 0
C Set value (SV)
C+1 Proportional band (P)
C+2 Tik = Integral time T
1
/sampling period γ (See note 1.)
C+3 Tdk = Derivative time Td/sampling period γ (See note 1.)
C+4
Sampling period
γ
C+5
2-PID parameter (α) (See note 2.)
PID forward/
reverse designation
C+6 0
Input range
0 Output range
C+7 to C+32 Work area (Cannot be accessed directly from program.)
Note 1.
What is set in words 2 and 3 is not the actual integral and derivative times,
but rather their values divided by the value of the sampling period
γ
.
2. Setting the 2-PID parameter (α) to 000 yields 0.65, the normal value.
Special Math Instructions Section 5-21
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