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x.00
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Menu 3
Unidrive SP Advanced User Guide
51
Issue Number: 10 www.controltechniques.com
5.5 Menu 3: Slave frequency, speed feedback, speed control and regen operation
Menu 3 relates to different functions depending on the drive mode selected as shown in the table below. The menus for some drive modes are
significantly different and therefore the complete menu is covered in different sections. Open-loop is different from Closed-loop vector and Servo
except that it shares a common block of parameters for the drive encoder. The drive encoder parameters are only described in the Closed-loop vector
and Servo section.
Frequency/Speed accuracy and resolution
Digital reference resolution
When a preset frequency/speed is used the reference resolution is 0.1Hz or 0.1rpm. Improved resolution can be obtained by using the precision
reference (0.001Hz or 0.001rpm).
Analog reference resolution
In Open-loop modes the frequency reference controlled by an analog input has a maximum resolution of 12bits plus sign, but this is reduced if the
window filter time for this input controller by Pr
7.26
is reduced below the default value of 4.0ms. The resolution of the frequency reference from
analog inputs 2 or 3 is 10bits plus sign.
In Closed-loop vector or Servo mode the resolution from analog input 1 is better than 16bits plus sign provided the speed reference is routed via
Pr
1.36
, Pr
1.37
or Pr
3.22
in high speed update mode. The resolution from analog inputs 2 or 3 is 10bits plus sign.
Accuracy
The absolute frequency and speed accuracy depends on the accuracy of the crystal used with the drive microprocessor. The accuracy of the crystal
is 100ppm, and so the absolute frequency/speed accuracy is 100ppm (0.01%) of the reference, when a preset speed is used. If an analog input is
used the absolute accuracy is further limited by the absolute accuracy and non-linearity of the analog input.
Drive mode section
Menu 3 functions
Open-loop
Frequency slaving
“Zero speed” and “at speed” detectors
Closed-loop vector and servo
Speed feedback, speed controller
“Zero speed”, “at speed” and overspeed
detectors, drive encoder
Regen
Regen control and monitoring functions
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