NFO
Drives
AB
2021
201013
‐
2
Operating
and
Installation
Manual
32
If rotation in both directions is required (e.g. at ±10V or ±10mA, stopping in the middle), set
Min Ain Spd
to negative
(–)
Max Ain Spd
.
5.11 Process regulation, PI regulator
The inverter is equipped with a PI regulator used for process regulation with an external actual value (sensor
signal) according to a selected setpoint value. The regulator can be used in both control mode
Frequency
and
Speed
. The regulator is enabled by either setting the
Op Mode (Setp Source)
parameter to
PI-Reg
in the control
mode used, or setting the correct digital input combination at the terminal if
Terminal
is the selected
source. For
backward compatibility with older NFO Sinus inverters, the process regulator can also be activated by setting
parameter
Control Mode = PI-Reg
.
Fig. 13. Process regulator overview
The process regulator unit (default kPa) is selected using the parameter
Unit
(both setpoint and actual value), see
Table 14. Whatever setpoint source is used, the regulator's actual value is by default taken from the analog input
AIN2 at terminal 22. The scaling of the actual value is controlled by parameters
Actual Min
och
Actual Max
which
translates the minimum and maximum signal level from the actual value input corresponding to the selected unit.
The regulator generates an output signal in the form of a setpoint (frequency or speed) in the range limited by
parameters
Min Frq
and
Max Frq, or Min Spd
and
Max Spd,
depending on the control mode chosen. When using
Control Mode = PI-Reg
the parameters used for scaling min and max frequency are
Min Freq
and
Max Freq
.
If a potentiometer or a sensor is used for the setpoint, their output signal is scaled to the chosen regulator unit by
parameters
Setpoint Min
and
Setpoint Max
. With parameters
Setpoint Min Limit
and
Setpoint Max Limit
, it is
possible to limit the range of the setpoint value.
Both AIN1 and AIN2 can be configured for voltage or current input individually, see 4.1.3, Table 8 and Table 15.
If desired, the parameters
Reg Off Limit
and
Reg On Limit
can be used to turn off motor when a certain actual value
has been reached, and then again turn on motor when actual value has dropped below the turn on limit. When any
of the parameters
Reg Off Limit
or
Reg On Limit
are zero, this functionality is disabled. The turn off function uses
the sleep frequency, therefore the sleep functionality cannot be used concurrently for some other purpose.
The regulator's sampling rate is 10 samples per second.
3006469-2022-04
