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instead of the Motor Axis.
Master Axis Encoder Revolution Counter
MasterAxis.MasterEncRevCount
This read-only parameter displays the number of whole revolutions that the master encoder signal has moved since powered up
(absolute) and can be found on the Online tabs on the Status and Master Setup views. The units for this parameter are always
revolutions since those are the units used by the drive and it's option modules. The value for this parameter comes from parameter
x.04 of the feedback module menu.
In order for this parameter to work properly, a master encoder must be connected to a position feedback module, and the
MasterAxis.SpeedFeedbackSelector must be configured properly.
Master Axis Encoder Position
MasterAxis.MasterEncRevPosition
This read-only parameter displays the number of fractions of a revolution that the master encoder signal has moved, and can be
found on the Online tabs of the Status and Master Setup views. The units for this parameter are always 1/(2^16) of a revolution since
those are the units used by the drive and it's option modules. The value for this parameter comes from parameter x.05 of the
feedback module menu.
In order for this parameter to work properly, a master encoder must be connected to a position feedback module, and the
MasterAxis.SpeedFeedbackSelector must be configured properly.
Master Axis Feedback Selector
MasterAxis.SpeedFeedbackSelector
The MasterAxis.Speed Feedback Selector parameter determines where the feedback device for the master signal is connected to.
NOTE
Early releases of the SM-EZMotion module only support a value of Slots 1, 2, or 3 (and NOT Drive). The master encoder feedback
signal must be connected to a SM-Universal Encoder Plus module fitted into one of the Unidrive SP option slots.
This parameter is read-only from within a user program.
Master Axis Characteristic Distance
MasterDistUnits.CharacteristicDistance
The Master Axis Characteristic Distance is the numerator in the scaling function used to define the relationship between user units of
the master and revolution(s) of the master encoder. The user must define how many master user units there are in X number of
revolutions of the master encoder. X in this case is the Master Axis Revs parameter (see below).
Example:
A master encoder is attached directly to a pulley measuring 3 inches in diameter. The user wishes to use units of Inches on the
master axis. The circumference of the pulley is therefore, Diameter *PI = 3.0 * 3.14 = 9.425 inches. This means the master
encoder would travel 9.425 inches for each revolution of the pulley. Therefore, the user would set the Characteristic Distance to
9.425 and the Master Rev to 1. If the encoder was attached instead to a different pulley that runs at a 3:1 ratio as the original
pulley, the user could still set the Character Distance to 9.425, but instead set the Master Revs to 3.
This parameter is read-only within a user program for revisions of PowrTools Pro software prior to version 4.1. PowerTools Per 4.1
and later allow the Master Axis Characteristic Distance to be modified within a user program. Extreme caution should be used to
prevent the change of scaling when the synchronized motion is active. The motor should be stopped and the drive disabled when
changing scaling factors in a program.
Changing this parameter within a user program or from an HMI will automatically clear the AbsolutePosnValid signal, and for
Absolute encoders the AbsoluteHomeDefined signal. This means that when the values are changed, the machine must be homed
again.
Master Axis Revs
MasterDistUnits.MasterRevs
The Master Axis Revs is the denominator in the scaling function used to define the relationship between user units of the master and
revolution(s) of the master encoder. The user must define how many master user units there are in X number of revolutions of the
master encoder. X in this case is the Master Axis Revs parameter. The number of user units in the ratio is the Master Axis
Characteristic Distance (see above).
Example:
A master encoder is attached directly to a pulley measuring 3 inches in diameter. The user wishes to use units of Inches on the
master axis. The circumference of the pulley is therefore, Diameter *PI = 3.0 * 3.14 = 9.425 inches. This means the master
encoder would travel 9.425 inches for each revolution of the pulley. Therefore, the user would set the Characteristic Distance to
9.425 and the Master Rev to 1. If the encoder was attached instead to a different pulley that runs at a 3:1 ratio as the original
pulley, the user could still set the Character Distance to 9.425, but instead set the Master Revs to 3.
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EZMotion User/Programming Guide
Revision: A8
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