Filter Objects

Filters provide linkage between motors and axes: motors are mapped to filters, and filters are mapped to axes. (It is not possible to map a motor directly to an axis without a filter.) Depending upon the algorithm employed, filters use such coefficients as gains, feed forward and torque limits.

Filter Configuration Attributes

The Filter Summary window lists Filter attributes in three tab pages:
"Config," "Coeffs," and "SERCOS."

Configuration Attributes: "Config" Tab Page

"Config" Filter attributes include configurations for standard and custom filter features.

Save to Flash-- Pre-selects current Filter settings for saving to flash memory. For more information on using Save to Flash, see description in the first part of this chapter.
View Sub-objects-- Shows all sub-objects for Filter object. For more information, see Object Summary Windows.
Motor Map-- Displays the Filter Motor Map Configuration window. For more information, see Object List Configuration Dialog Boxes.
Algorithm -- Software filter algorithm. There are five types:

None -- Filter is OFF. No algorithm is applied.

PID -- Proportional Integral Differential algorithm.

PIV -- Proportional Integral Velocity.

PIV1 -- Proportional Integral Velocity.

SERCOS Drive -- SERCOS protocols applied. (See "SERCOS Coefficients" below.)

User -- User-defined algorithm defined in firmware. (For more information, please contact MEI.)

Configuration Attributes: "Coeffs" Tab Page

The display of filter coefficients changes according to the Algorithm chosen (selectable from the Filter / General panel). The algorithm combo box on the Coeffs tab merely changes how the coefficients are displayed. It changes the row headers and displays N/A for coefficients that are not used for the selected algorithm. If the algorithm of a filter object does not match the algorithm being displayed, then N/A is displayed for all coefficients.

Each set of coefficients is described in separate tables below.

PID Coefficients

PID coefficients are defined in the table below.

Filter Coefficients (PID Algorithm)
Coefficient	Description
Kp	Proportional gain
Ki	Integral gain
Kd	Derivative gain
Kpff	Position feed forward gain
Kvff	Velocity feed forward gain
Kaff	Acceleration feed forward gain
Kfff	Friction feed forward gain
ImaxMoving	Position loop integration maximum (while moving)
IMaxRest	Position loop integration maximum (while resting)
DRate	Derivative sub-sampling rate
Output Limit	Voltage command output limit
Output Limit High	Maximum command output voltage limit.
Output Limit Low	Minimum command output voltage limit.
Output Offset	Offset added to output.
Ka0	Fast Fourier transform (FFT) testing gain (0)
Ka1	Fast Fourier transform (FFT) testing gain (1)
Ka2	Fast Fourier transform (FFT) testing gain (2)

PIV Coefficients

PIV coefficients are described in the table below.

Filter Coefficients (PIV Algorithm)
Coefficient	Description
Kpp	Position loop proportional gain
Kip	Position loop integral gain
Kpv	Velocity loop proportional gain
Kvff	Velocity feed forward gain
Kaff	Acceleration feed forward gain
Kfff	Friction feed forward gain
ImaxMoving	Position loop integration maximum (while moving)
IMaxRest	Position loop integration maximum (while resting)
Kdv	Velocity estimate feedback gain
Output Limit	Voltage command output limit
Output Limit High	Upper voltage command output limit.
Output Limit Low	Lower voltage command output limit.
Output Offset	Offset added to output
Kiv	Velocity loop integral gain
VintMax	Velocity loop integration maximum
Ka0	Fast Fourier transform (FFT) testing gain (0)
Ka1	Fast Fourier transform (FFT) testing gain (1)

SERCOS Coefficients

SERCOS coefficients are described in the table below.

Filter Coefficients (SERCOS Algorithm)
Coefficient	Description
IDN Value 0	Value of IDN mapped to this coefficient.
. . .	. . .
IDN Value 15	Value of IDN mapped to this coefficient.
Kvff	Velocity feed forward gain
Kaff	Acceleration feed forward gain
Kfff	Friction feed forward gain
Ksff	Feed forward scale factor.

Configuration Attributes: "SERCOS" Tab Page

The SERCOS tab page maps gain values to IDNs. If the map value is 0, then the gain is not mapped to an IDN. If the gain value is non-zero, then the MPI functions for getting and setting gain values will automatically read/write the gain values to the drive via the SERCOS service channel.