Rockwell Automation GMLC Reference Manual - Manual (Page 523)

Publication GMLC-5.2 - November 1999
486 Motion Variables
The average velocity of the imaginary axis is always zero, because the
imaginary axis has no actual position and thus no actual velocity to
average. Use command velocity for the imaginary axis.
Command Velocity
Command_Velocity is the desired or commanded speed of a servo axis or
the imaginary axis in axis position units per second, as generated by any
previous motion blocks. It is calculated as the rate of command position
change with time. Unlike average velocity, however, command velocity is
a signed value—the sign (+ or -) depends on which direction the axis is
moving.
In the Tag Explorer select both Axis System Variables and the desired
axis, then select Command_Velocity in the Tag Window. See the figure in
this chapter for more information on command velocity.
Command_Velocity is a signed floating-point value with up to 15
significant digits. Its resolution does not depend on the averaged velocity
timebase, or the conversion constant of the axis.
Servo Output Level
Servo_Output_Level is the current voltage level of the servo output of a
servo axis. For the Compact, Servo_Output_Level_mA is the current
output level of the servo output of a servo axis configured for current
output. Use Servo_Output_Level if the servo output for the axis is
configured for voltage (±10V), and Servo_Output_Level_mA if it is
configured for current (±150 mA).
In the Tag Explorer, select both Axis System Variables and the desired
axis, then select Servo_Output_Level in the Tag Window.
Analog Offset Setpoint
Analog_Offset_setpoint is the analog value, set in an Analog Offset
function block’s Setpoint field, which the motion controller sets and
holds.
In the Tag Explorer select both Axis System Variables and the desired
axis, then select Analog_Offset_setpoint in the Tag Window.