Azbil C1M - SP Lag

5-27
Chapter 5. Functions
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SP lag
The SP lag is a filter function to prevent sudden changes in the SP used in control
operations when the SP changes. Use the setting below for SP lag.
Item (bank) Display Description Initial value User level
SP lag constant
(extended tuning bank)
SP.LG
0.0 to 999.9
(0.0 = no effect)
0.0 Advanced
• If CtrL (control method) is set to “1” (PID control), this item is displayed and the
setting can be changed.
• The function of SP.LG (SP lag constant):
If 0.0 is set: The SP lag function has no effect.
If 0.1 or more is set: The larger the constant, the smaller the amount of MV
change when the SP is changed, and the more strongly overshoot is suppressed.
• When the SP changes, the initial output value of the filter function that is input to
the PID control operation is reset as follows.
• Reset to the SP when PID control starts after RUN + MANUAL modes are
switched to RUN + AUTO modes
• Reset to the PV when PID control starts after READY + AUTO modes are
switched to RUN + AUTO modes
• Reset to the PV when PID control starts after the value set for “Output at PV
alarm” is output
• Reset to the SP when PID control starts after AT ends normally
• Reset to the PV when PID control starts after AT ends abnormally
• Reset to the PV if the settings below are changed in RUN + AUTO modes:
Control method
Heat/cool control
Control operation
Sampling cycle
Control algorithm
• Reset to the PV if PID control is initialized according to the setting for “Initial
output type (mode) of PID control” (C21) in RUN + AUTO modes