B&R ACOPOSinverter P84, User Manual

Page: 236 / 405

Programming guidelines
236 ACOPOSinverter P84 User's Manual 2.10
Scaling of feedback and references:
• Parameters PIF1 , PIF2
Can be used to scale the PID actual value (sensor area).
This scaling absolutely must be retained for all further parameters.
• Parameter PIP1 , PIP2
Can be used to scale the adjustment range, i.e. the reference.
The control range must be within the sensor range.
The maximum scaling parameter value is 32767. To simplify the start-up process, it is recommended that you use
values as close to this maximum value as possible, while still staying within a power of 10 of the real values.
Example (see curve below): Adjustment of the volume in a tank, between 6 m
3
and 15 m
3
.
•
Used 4-20 mA sensor, 4.5 m
3
for 4 mA, 20 m
3
for 20 mA, where PIF1 = 4500 and PIF2 = 20000.
• Control range 6 to 15 m
3
, where PIP1 = 6000 (min. reference) and PIP2 = 15000 (max. reference).
•
Example references:
– rP1 (internal reference) = 9500
– rP2 (preset reference) = 6500
– rP3 (preset reference) = 8000
– rP4 (preset reference) = 11200
The menu [DISPLAY CONFIG.] enables a user-specific adaptation of the name of the displayed unit and its format.
Control range
(Reference)
PIP2 (15000)
PIP1 (6000)
PIF1
(4500)
PIF2
(20000)
PID feedback
Additional parameters:
•
rSL :
In this way, the threshold value of the PID deviation from which the PID controller is reactivated (wake-up)
after a stop as a result of the exceeding of a time threshold of the low frequency (tLS) can be determined.
• Inverted offset direction (PIC) : If PIC = nO , with a positive deviation, the motor speed increases
Example: Pressure control with a compressor. If PIC = YES , with a positive deviation the motor speed drops
Example: Temperature control using a cooling fan.
• The integral gain may be short-circuited by a logic input.
•
An alarm on the PID feedback may be configured and indicated by a logic output.
• An alarm on the PID error may be configured and indicated by a logic output.