3. Instructions
656
CS/CJ/NSJ Series Instructions Reference Manual (W474)
Example Programming
z Interrupting PID Control to Perform Autotuning
• At the rising edge of CIO 0.00 (OFF to ON), the work area in D211 to D240 is
initialized according to the parameters (shown below) set in D200 to D208. After
the work area has been initialized, PID control is executed and the manipulated
variable is output to CIO 20.
• While CIO 0.00 is ON, PID control is executed at the sampling period intervals
according to the parameters set in D200 to D210. The manipulated variable is
output to CIO 20.
• The PID constants used in PID calculations will not be changed even if the
proportional band (P), integral constant (Tik), or derivative constant is changed
after CIO 0.00 turns ON.
• At the rising edge of W 0.0 (OFF to ON), SETB(532) turns ON bit 15 of D209
(C+9) and starts autotuning. When autotuning is completed, the calculated P, I,
and D constants are written to C+1, C+2, and C+3. PID control is then restarted
with the new PID constants.
PIDAT
10
D200
20
0.00
S
C
D
W0.0
SETB
D209
#000F
C: D200
C+1: D201
C+2: D202
C+3: D203
C+4: D204
C+5: D205
C+6: D206
C+7: D207
C+8: D208
C+9: D209
C+10: D210
C+11: D211
C+40: D240
012C
0064
04B0
0190
0032
0000
0494
0000
0000
0000
0000
Work area
Proportional band: 10.0%
Integral time: 120.0 s
Derivative time: 40.0 s
Sampling
period: 0.5 s
Reverse operation (bit 00: 0), PID constant change enable setting = OFF
(bit 01: 0), set value = manipulated variable output 50% (bit 03: 1), 2-PID
parameter = 0.65 (bits 04 to 15: 000 hex)
Manipulated variable output range: 12 bits (bits 00 to 03: 4 hex),
Integral/derivative constant: time designation (bits 04 to 07: 9 hex)
Input range: 12 bits (bits 08 to 11: 4 hex),
Manipulated variable output limit control disabled (bit 12: 0)
AT Command Bit OFF (bit 15: 0),
AT Calculation Gain = 1.00 (bits 00 to 11: 000 hex)
Limit-cycle Hysteresis = 0.20%
PID starting integral manipulated variable designation = start from same
integral manipulated value as manipulated variable output designation
(bit 14: 0 and bit 13: 0)
Parameters
PV:
CIO 10
MV output: CIO 20
to
PID
calculation
Set value: 300
CIO 0.00
W0.00
PV
SV
MV
PID control PID control
AT executing
PID control starts.
Calculated PID
constants are set.
Bit 15 of D209
Time
Time
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