Chapter 5 Function parameter
96
PID Output
control amount
P
Td*s+1
1
Target
amount -
+
Feedback amount
Ti
1
S
1
Figure 5-31:Flow diagram of process PID principle
Panel potentiometer reference
Multi-stage command setting
This parameter is used to select the process PID target value reference channel.
The set target value of process PID is a relative value, the setting range is from 0.0% to
100.0%. The feedback value of PID is also a relative value, the role of PID is to remain the
same for the two relative values.
Panel potentiometer setting
This parameter is used to select the process PID feedback signal channel.The feedback
value of process PID is also a relative value, the setting range is from 0.0% to 100.0%.
PID reference feedback range
PID reference feedback range is a dimensionsless unit for PID setting display(d0.15) and
PID feedback display(d0.16).
The 100.0% of the relative value of PID reference feedback corresponds to a setting
feedback range(E2.04). If E2.04 is set to 2000, when PID setting is 100.0%, PID setting
display(d0.15) will be 2000.
PID inversion cutoff
frequency
0.00 to F0.19(Maximum frequency)
In some cases, only when the PID output frequency is negative (i.e.the inverter reverses),
PID can control the reference value and the feedback value to the same states, but the excessive
inversion frequency is not allowed in some occasions, E2.05 is used to the upper limit of
determine inversion frequency.
When the deviation between PID reference value and PID feedback value is less than
E2.06, PID will stop regulating action. Thus, when the deviation is lesser, the output frequency
will be stable, it is especially effective for some closed-loop control occasions.
PID differential limiting
The role of the differential is more sensitive in PID regulator, is likely to cause system