Mitsubishi Electric MELSEC-Q/L - Page 751

7 APPLICATION INSTRUCTIONS
7.18 PID Instruction
749
7
Program example in auto tuning (step response method) + PID control
•Device
•Program
Device Description
X2 Start PID control after auto tuning.
X3 Start PID control (without auto tuning).
M0 Auto tuning setting flag
M1 Auto tuning operation flag
M2 Stop auto tuning.
M3 PID running
M14 Auto tuning operation flag
Set the SV. <50°C>
Set the input filter
constant (α). <70%>
Set the derivative gain (K
D). <0%>
Set the ULV. <On time: 2 seconds>
Set the LLV. <On time: 0 seconds>
Start the auto tuning setting.
Auto tuning action status flag
Set the sampling time (T
S) for auto
tuning. <3 seconds>
Turn on the auto tuning execution
bit in action setting (ACT)
parameter.
Set the auto tuning output cycle.
<On time: 1.8 seconds>
Set the sampling time (T
S) for
normal PID action. <500ms>
Input the PV to the I/O data area
from the A/D converter module.
Initialize PID output.
Execute the PID instruction.
PID action being performed
Check the auto tuning action.
End the auto tuning processing.
Switch to the normal PID action.
Heater output
Write the manipulated value
to the D/A converter module.
Error