Emerson EZMotion User Manual page 137

scaling capabilities of the drive parameters are minimized.
Velocity Command
If the user selects Velocity Command from the list of predefined parameters, EZMotion will constantly write the present value
of the parameter VelCommand to the Analog Output. Velocity Command is defined as the velocity commanded by EZMotion
to the drive, and is completely independent of feedback. Selecting Velocity Command from the list will automatically configure
the scaling parameters to the correct units and default values. The units for VelCommand are User Distance Units/Unit Time.
Velocity Feedback
If the user selects Velocity Feedback from the list of predefined parameters, EZMotion will constantly write the present value of
the parameter VelFeedback to the Analog Output. Velocity Feedback is defined as the velocity measured by the feedback
device (i.e. encoder, resolver, etc.). Selecting Velocity Feedback from the list will automatically configure the scaling
parameters to the correct units and default values. The units for VelFeedback are User Distance Units/Unit Time.
Fast Mode Parameters
When selecting any of the following four parameters from the Source list, the Unidrive SP/Digitax ST has the ability to operate
in a "Fast Mode" where the drive updates the Analog Output value every 250 microseconds instead of the normal minimum of
4 milliseconds. In order to get the faster update, the user must also select High Speed from the Output Mode list box.
Menu 3.02 (Speed)
Selecting this Source will write the Unidrive SP/Digitax ST Speed Feedback to the Analog Output directly. The units for this
selection are always RPM regardless of the User Unit configuration in EZMotion.
Menu 4.02 (Active Current)
Selecting this Source will write the Unidrive SP/Digitax ST Active Current to the Analog Output directly. The Active Current is
the torque producing current being created by the drive. The units for this selection are Amps.
Menu 4.17 (Reactive Current)
Selecting this Source will write theUnidrive SP/Digitax ST Reactive Current to the Analog Output directly. The Magnetizing
Current is the current produced to generate the magnetic field or flux for an induction motor. The units for this selection are
Amps.
Menu 5.03 (Output Power)
Selecting this Source will write the Unidrive SP/Digitax ST Output Power to the Analog Output directly. The Output Power is
the product of the Output Voltage and the Active Current. The units for this selection are kW.
Module Variable
The Module Variable parameter is only available once the user has selected User Defined Module Variable from the Source
list box. The field is used to define what EZMotion parameter will control the Analog Output. This means that the selected
module parameter will directly determine the value of the Analog Output based on the Max and Min scaling values entered on
this view.
Popup Variables Button
The Popup Variables button is only available once the user has selected User Defined Module Variable from the Source list
box. Click Popup Variables and the Select Variables From Tree window will open containing the list of variables that can be
dragged into the Module Variable text box.
Menu
The Menu parameter is only available once the user has selected User Defined SP Menu from the Source list box. In this text
box, the user enters the desired Unidrive SP/Digitax ST menu parameter that will control the Analog Output. The parameter is
entered in the format of MM.PP where MM is the Menu number, and PP is the Parameter number. The range for this
parameter is 0.00 to 21.51. For more information on the Unidrive SP parameter set, please refer to the Unidrive SP User
Guide or Unidrive SP Advanced User Guide and for more information on Digitax ST parameter set, please refer to the Digitax
ST User Guide.
Scale
The Scale parameter is only available once the user has selected User Defined SP Menu from the Source list box. This
parameter allows the user to enter a scaling factor that is multiplied with the value of the Menu parameter to determine the
output value. The formula to determine the actual output is as follows:
Maximum Value
This defines the Maximum Value of the Source parameter that will yield the corresponding Maximum Output for the Analog
Output. The source parameter may be greater than this maximum value, however the Max Value and Max Output are used
together to define a single point on the curve used for linear interpolation.
Maximum Output
In order to scale the Analog Output value into the proper scale and units for the selected Module Variable, the user must
define the maximum scale value and the minimum scale value. EZMotion then uses linear interpolation to determine the value
to be sent to the analog output.
The Maximum Output is the value that will be sent to the Analog Output when the Module Variable is equal to the Maximum
Value.
EZMotion User/Programming Guide
Revision A8
⎛ ⎞ Scaling Factor
Parameter Value
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²
⎝ ⎠
Parameter Max
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= Analog Output
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