XGB Analog edition manual
15 - 16
[ Figure 15.11 Example of DeadBand setting ]
If setting deadband as in the figure, the PID control built in XGB may regard the error between PV
and set value as 0 as long as PV is within the available scope of deadband from set value.
That is, in this case, the change of MV is reduced. The available scope of setting is between 0 ~
65,535 and if it is set as 0, it does not work.
(p) Differential Filter Value Setting
It sets the coefficient of differential filter. Since differential control outputs in proportion to gradient
of error and gradient of PV change, it may suddenly change MV as it generates a large response
to instantaneous noise or disturbance. To prevent it, XGB series uses a value to which PV is
filtered mathematically for differential control. Differential filter value is the coefficient to determine
the filter degree for differential control. As smaller differential value set, as stronger differential
operation is. The available scope is between 0 ~ 65,535 and if it is set as 0, the differential filter
does not work.
(q) Setting set value ramp
Since the drift is suddenly large if SV is heavily changed during PID control, MV is also changed
heavily to correct it. Such an operation may cause excessive operation of a system to control and
a drive. To prevent it, SV ramp is used, changing SV gradually step by step when modifying SV
during operation. If using the function, SV is gradually changed by SV ramp when SV is changed
during PID control. At the moment, SV ramp setting represents the frequency of PID operation
cycle taken from when SV starts changing to when it reaches to the final SV. For instance, if SV
is to be changed from 1000 to 2000 during operation as PID operation cycle is 10ms and its SV
ramp is 500, SV may reach to 2000 after 500X10ms = 5 seconds, that is, as it increases each 2
per operation cycle and after the 500th operation scans. The available scope of setting is
between 0 ~65,535 and it is set as 0, it does not work.
[ Figure 15.12 SV Ramp function ]
If SV Ramp is not used
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