Emerson EZMotion User Manual page 72

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, EZMotion 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)
SC.EnDat (Heidenhain®)
Encoder Setup Parameters
Encoder Supply Voltage
Because of the wide variety of encoders supported by the Unidrive SP/Digitax ST 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.
NOTE
Be sure not to configure a supply voltage greater than that supported by the encoder. The Unidrive SP/Digitax ST and SM-Universal
Encoder Plus cannot protect against possible damage to the encoder if the supply voltage is set too high.
Enable Auto Encoder Configuration
When a SC.Hiper, SC.EnDat, or EnDat encoder is being used, the Unidrive SP/Digitax ST and/or SM-Universal Encoder Plus
module can interrogate the encoder on power-up, and acquire many of the encoder setup parameters automatically. To enable this
feature, the Enable Auto Encoder Configuration check box must be selected. When the check box is selected (active) the Encoder
Turns, Encoder Comms Resolution, and Equivalent Lines Per Revolution parameters will appear dimmed, implying that the user no
longer needs to configure those parameters. If the check box is clear, then the user must specify the correct values for these three
parameters (Encoder Turns, Encoder Comms Resolution, and Equivalent Lines Per Revolution).
The aforementioned encoder parameter values are stored in non-volatile memory embedded in the encoder. The values stored in
NVM cannot be changed by the user.
Encoder Turns
This parameter determines the maximum number of revolutions before the Rev Counter register (3.28 or x.04) rolls over. If using an
absolute encoder, this should be set at the maximum number of turns of the absolute encoder or lower. The maximum number of
turns is defined as follows:
Maximum Turns = 2
If the Enable Auto Encoder Configuration check box is selected, then the user does not need to enter this parameter, and the
Encoder Turns box will appear dim.
Encoder Comms Resolution
Where encoder communications is used to initially read the absolute encoder position (SC.Hiper or SC.EnDat), the comms
resolution must be set to the maximum resolution of the absolute position data.
60
Actual Encoder Lines Per Rev
N
, where N is the Encoder Turns parameter
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= ELPR/Lines Per Rev Divider
= 128123 / 1000 = 128.123
EZMotion User/Programming Guide
Revision: A8