YASKAWA iQpump Series Programming Manual page 25

The PI Setpoint will be read from:
Parameter b5-19
Modbus Register 06H
D1-01
Terminal A1
Serial Comm.
Option PCB
In some situations there are two feedback inputs. The drive can be programmed to maintain a set differential between two analog signals.
If input A2 is configured as a "PI Differential Mode" (H3-09 = "16: PI Differential"), then the iQpump drive will maintain a set
difference between the measurements read on inputs A1 and A2. This differential setpoint is programmed by parameter (b5-07).
b5-01 PI Mode
■
Setting
0 Disabled (factory default)
1 Enabled
2 Fref+PI
The iQpump drive can be used as a stand-alone PI controller. If PI functionality is selected by parameter b5-01, the iQpump drive will
adjust its output to cause the feedback from a transmitter to match the PI setpoint (b5-19). The setting of b5-01 will determine whether PI
functionality is disabled (b5-01 = "0: Disabled"), enabled (b5-01 = "1: Enabled"), or enable with the output of the PI function used to
trim a Speed Command (b5-01 = "3: Fref+PI").
b5-02 Proportional Gain Setting
■
Setting Range: 0.00 to 25.00
Factory Default: 2.00
The proportional gain will apply a straight multiplier to the calculated difference (error) between the PI Setpoint and the measured
transmitter feedback at terminal A2. A large value will tend to reduce the error but may cause instability (oscillations) if too high. A small
value may allow to much offset between the setpoint and feedback (See
b5-03 Integral Time Setting
■
Setting Range: 0.0 to 360.0 sec
Factory Default: 5.0 sec
The Integral factor of PI functionality is a time-based gain that can be used to eliminate the error (difference between the setpoint and
feedback at steady state). The smaller the Integral Time set into b5-03, the more aggressive the Integral factor will be. To turn off the
Integral Time, set b5-03 = 0.00.
YASKAWA TM.iQp.02 iQpump Drive Programming Manual
Table 1 PI Setpoint Options
Status of b5-18=
1
0
0
0
0
0
Description
Figure 22
If these conditions are true
Status of Modbus Register
0Fh bit 1
N/A
ON
OFF
OFF
OFF
OFF
on following page).
Status of b1-01=
N/A
N/A
0
1
2
3
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