Emerson EZMotion, User Manual

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EZMotion User/Programming Guide
61
Revision A8 www.controltechniques.com
If the Enable Auto Encoder Configuration check box is selected, then the user does not need to enter this parameter, and the
Encoder Comms Resolution box will appear dim.
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 check box is selected, then the user does not need to enter this parameter, and the
Equivalent Lines Per Rev box will appear dim.
Lines Per Rev Divider
The Equivalent Lines Per Revolution 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 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 100 k baud and 2 M baud.
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, 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)
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