User`s guide

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CHAPTER 6 - DETAILED PARAMETER DESCRIPTION
6.3.5.3
PID Start-up Guide
Please findbelowa start-up procedure forthe PIDregulator:
Initial Definition
1)
Process - Definition of the PID action type that the
process requires: direct or reverse. The control action
must be direct (P527 = 0) when it is required to increase
the motor speed and so also increment the process
variable. Otherwise select reverse (P527 = 1).
Examples:
a)
Direct: pump driven by inverter and filling a tank
where the PID regulates the tank level. To increase
the level height (process variable) the flow must be
increased and consequently also the motor speed
must be increased.
b)
Reverse: fan driven by an inverter to cool a cooling
tower, with thePID controlling the temperature of this
tower. When it is required to increase the tower
temperature (process variable), the cooling power
must be decreased by reducing the motor speed.
NOTE!
When the PID function (P203 = 1) is set:
The digital input DI3 is automatically set to manual/
automatic(P265 = 15). Thus when DI3 is open,the manual
modeis activated andwhenDI3 is closed, thePID regulator
starts to operate (closed loop control - automatic mode).
If the function of this digital input (DI3) is changed, the
operation of the inverter will be always in manual mode.
If P221 or P222 is equal to 1, 4, 5, 6, 7 or 8 the E24 error
message will be displayed. Set P221 and P222 equal to 0
or 2 according to the requirement.
The JOG and the FWD/REV functions are disabled. The
inveter enabling and disabling commands are defined by
P229 and P230.
In the manual mode, the frequency reference is given by
F*, as shown in figure 6.1.
When the operation mode is changed from manual to
automatic, P525 is automatically set to the value of P040
if P536 = 0 (at the instant immediately before the
commutation). Thus when the setpoint is defined by P525
(P221 or P222 = 0), the changingfrom manual to automatic
is smooth [there is not abrupt oscillation in the frequency
(speed)reference].
The analog output can be programmed to indicate the
process variable (P040) or the PID setpoint with P251 = 6
or 9, respectively.
Figure 6.28 shows an application example of an inverter
controlling a process in closed loop (PID regulator).