User guide

Configuring an Application www.controltechniques.com 45
Example:
The true number of encoder lines per rev (or electrical
cycle) is 128.123. Since The Equivalent Lines Per Rev
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. The list box allows the user to select from
various baud rates between 100kbaud and 2Mbaud.
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 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)
7.2.2.5 SM-Resolver Module View
Some applications require the use of resolver feedback
instead of encoder feedback. In this case, a SM-Resolver
module provides an interface between the resolver and the
Unidrive SP, to be used as position and velocity feedback
for the SM-EZMotion module. The SM-Resolver also
provides a simulated quadrature encoder output that can
be sent to another device for position feedback
information.
If Resolver is selected in the Slot # Module list box, the
remainder of the view will have configuration parameters to
define the resolver properties. The hierarchy automatically
updates to show that a SM-Resolver module is populated
in that specific slot, see Figure 62.
Figure 62: Slot # View (SM-Resolver Module)
Following is a description of each of the parameters related
to performance and functionality of the SM-Resolver
module. For SM-Resolver module installation instructions,
or other SM-Resolver module information, please refer to
the SM-Resolver User Guide.
Resolver Setup Parameters
Resolver Excitation
The Resolver Excitation parameter defines the voltage
level of the excitation signal sent out to the resolver
hardware. By entering the turns ratio of the resolver device,
the SM-Resolver module will change the excitation signal
voltage accordingly. The resolver manufacturer should
specify the turns ratio of the resolver. Supported turns
ratios are 3:1 and 2:1.
Equivalent Lines Per Rev
The Equivalent Lines Per Rev parameter is used to define
the effective resolution of the resolver in terms of Lines per
Rev of a quadrature encoder. This parameter can be set to
256, 1024, or 4096. The setting of this parameter can limit
the maximum velocity of the system depending on the
Actual Encoder Lines Per Rev = ELPR/Lines Per Rev Divider
= 128123 / 1000 = 128.123