Chapter 10 Built-in PID Functions
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(4) _PIDn_AW2D (PID Anti Wind-up 2 Disable)
- Setting Area
K DEVICE AREA : m
Unit : Bit
If this bit is turned OFF at the user’s will, The Anti Wind-up2 function is inactivated.
The Anti Wind-up function is described in detail in 10.6.
If the corresponding bit is Off, [Default] Anti Wind-up2 is enabled.
(5) _PIDn_REM_RUN (PID REMote RUN)
- Setting Area
K DEVICE AREA : m
Unit : Bit
This is the external operation instruction of PIDRUN and has the same effect as when the contact of
PIDRUN is turned On/Off. In fact, PIDRUN performs an OR operation of the “PIDRUN input oondition”
contact and the corresponding bit in order to decide whether to perform the operation. Using this function
enables you to assign the operation contact of PIDRUN to a fixed address, facilitating easier use of
external input/output devices such as HMI.
If the corresponding bit is Off, [Default](the contact is Off) PIDRUN comes to STOP.
(6) _PIDn_P_ov_PV (PID P on PV)
- Setting Area
K DEVICE AREA: m
Unit : Bit
This sets the P operation source of the corresponding PID loop to PV. P operation is performed on ERR or
PV. P operation moves relatively slowly to a stable state when using PV than when using ERR under the
unstable instantaneous control due to initial response or disturbance. This implies that the change in output
is slow and a heavy load is not imposed on the driver. But, with the change in the range of the internal
operation value, the Anti Wind-up function does not operate.
If the corresponding bit is Off, PID performs P operation on the ERR value and, if it is On, P operation is
performed on the PV value.
(7) _PIDn_D_on_ERR (PID D on ERRor)
- Setting Area
K DEVICE AREA : m
Unit : Bit
This sets the D operation source of the corresponding PID loop to ERR. D operation is performed on ERR
or PV. In case of D operation using ERR, D response shows a dramatic change at the moment SV is
changed by the user and an excessive input may be applied to the driver. To prevent this, the method of
using PV for D operation is used and the [Default] value is also set to support D operation using PV. Using
ERR without this algorithm turns the corresponding bit On.
If the corresponding bit is Off, PID performs D operation on the PV value and, if it is On, D operation is
performed on the ERR value.
Note
_PIDn_REM_RUN
This bit is stored in the K device even though the PLC stops. If the PLC is stopped and
restarted with this bit On (eg. power outage), the system is initialized at the first scan and then
PIDRUN operates.
