User guide

42 www.controltechniques.com SM-EZMotion Module User Guide
If the Enable Auto Encoder Configuration checkbox is
selected, then the user does not need to enter this
parameter, and the Encoder Comms Resolution box will
appear dimmed.
Equivalent Lines Per Revolution
When sin/cos signals are used, the equivalent number of
encoder lines per revolution must be set up correctly to
give the correct speed and position feedback. The
Equivalent Lines Per Revolution (ELPR) is defined as
follows:
For SC.Hiper, SC.EnDat and SC.SSI encoders, the sine
wave signal frequency can be up to 166 kHz, but the
resolution is reduced at higher frequencies. The table
below shows the number of bits of interpolated information
at different frequencies and with different voltage levels at
the drive encoder port. The total resolution in bits per
revolution is the ELPR plus the number of bits of
interpolated information.
If the Enable Auto Encoder Configuration checkbox is
selected, then the user does not need to enter this
parameter, and the Equivalent Lines Per Rev box will
appear dimmed.
Lines Per Rev Divider
The Equivalent Lines Per Revolution (ELPR) parameter is
divided by this value. This can be used when an encoder is
used with a linear motor where the number of counts or
sine waves per pole is not an integer.
Example:
The true number of encoder lines per rev (or electrical
cycle) is 128.123. Since the Equivalent Lines Per Rev
(ELPR) parameter must be a whole number, ELPR should
be set to 128123, and then the Lines Per Rev Divider would
be set to 1000 resulting in the following equation:
Encoder Comms Baud Rate
This parameter defines the baud rate for the encoder
communications. When using Hiperface encoders, the
baud rate is fixed at 9600 and cannot be changed.
Simulated Encoder Output Parameters
Encoder Simulation Source
The SM-Universal Encoder Plus module has a feature that
allows the user to send out a simulated encoder output
signal for use by an external device. The Encoder
Simulation Source is used to define the source of the
encoder signal. By default, the Source will be configured as
the SM-Universal Encoder Plus position (x.05). Any drive
parameter in the form of a 0-65535 rollover counter can be
used as the source parameter. Use this field to enter the
desired drive source parameter (between 00.00 and
21.51).
By default, the SM-EZMotion module configures the
simulated output to work in Quadrature mode. In order to
change the mode, the user will have to change the Drive
Menu Initialization file.
Encoder Simulation Numerator
To add some flexibility to the Simulated Encoder Output
signal, the SM-Universal Encoder Plus module allows the
user to scale the output signal by multiplying the source
with scaling factor. The scaling factor is made up of a
numerator and denominator allowing the user to achieve
nearly any ratio. By default, the Numerator and
Denominator are 1.000 implying that the actual output
value is equal to the Source value. Following is an equation
that defines the use of the Numerator and Denominator
parameters.
Simulated Encoder Output Signal = Simulated Encoder
Source * (Numerator/Denominator)
Encoder Simulation Denominator
To add some flexibility to the Simulated Encoder Output
signal, the SM-Universal Encoder Plus module allows the
user to scale the output signal by multiplying the source
with scaling factor. The scaling factor is made up of a
numerator and denominator allowing the user to achieve
nearly any ratio. By default, the Numerator and
Denominator are 1.000 implying that the actual output
value is equal to the Source value. Following is an equation
that defines the use of the Numerator and Denominator
parameters.
Simulated Encoder Output Signal = Simulated Encoder
Source * (Numerator/Denominator)
7.2.2.4.1.2 SC.EnDat (Heidenhain®)
Encoder Setup Parameters
Encoder Supply Voltage
Because of the wide variety of encoders supported by the
Unidrive SP and the SM-Universal Encoder Plus module,
the user must have the ability to define the voltage supplied
to the encoder hardware. The available voltage levels are
5V, 8V, and 15V and are selectable from the list box on the
Encoder view.
Position Feedback Device ELPR
Ab Number of lines per revolution
Fd, Fr Number of lines per revolution / 2
SC.Hiper, SC.EnDat, SC.SSI Number of sine waves per revolution
Volt / Freq 1,000 5,000 50,000 100,000 150,000
1.2 11 11 11 10 10
1.0 11 11 10 10 9
0.8 10 10 10 10 9
0.6 10 10 10 9 9
0.4 9 9 9 9 8
Actual Encoder Lines Per Rev = ELPR/Lines Per Rev Divider
= 128123 / 1000 = 128.123