243
Parameter Settings
Item Contents Setting range
Set value (SV) This is the target value of the process being
controlled.
Binary data (of the same
number of bits as specified for
the input range)
Proportional band This is the parameter for P control expressing
the proportional control range/total control
range.
0001 to 9999 (4 digits BCD);
(0.1% to 999.9%, in units of
0.1%)
Tik This is a constant expressing the strength of
the integral operation. As this value increases,
the integral strength decreases.
0001 to 8191 (4 digits BCD);
(9999 = Integral operation not
executed)
Tdk This is a constant expressing the strength of
the derivative operation. As this value
increases, the derivative strength increases.
0000 to 8191 (4 digits BCD)
Sampling period
This sets the period for executing the PID
operation.
0001 to 1023 (4 digits BCD);
(0.1 to 102.3 s, in units of
0.1 s)
PID
forward/reverse
designation
This is the parameter that determines the
direction of the proportional operation.
0: Reverse operation
1: Forward operation
2-PID parameter
(α)
This is the input filter coefficient. Normally use
0.65 (i.e., a setting of 000). The filter efficiency
decreases as the coefficient approaches 0.
000:
α = 0.65
Setting from 100 to 199 means
that the value of the rightmost
two digits is set from α= 0.00
to
α= 0.99.
Input range
This is the number of input data bits.
0: 8 bits
s
7: 15 bits
8: 16 bits
PID CONTROL Operation Execution Condition OFF
All
data that has been set is retained. Then the execution condition is OFF
, the
operation
amount can be written to the output word
(D) to achieve manual con
-
trol.
Rising Edge of the Execution Condition
The
work area is initialized based on the PID parameters that have been set and
the
PID control operation is begin. Sudden and radical changes in the operation
output
amount are not made when
starting operation to avoid adverse af
fect on
the controlled system (bumpless operation).
When
PID parameters are changed, they first become valid when the execution
condition changes from OFF to ON.
Execution Condition ON
The PID operation is executed at the intervals based on the sampling period,
according to the PID parameters that have been set.
Sampling Period and PID Execution Timing
The sampling period is the time interval to retrieve the measurement data for
carrying out a PID operation. PID(––), however, is executed according to
C200HS cycle time, so there may be cases where the sampling period is ex-
ceeded. In such cases, the time interval until the next sampling is reduced.
PID Control Method C200HS
PID control operations are executed by means
of PID control with feed-
forward control (two degrees of freedom).
Special Math Instructions Section 5-21