The target speed is displayed in a plot, both graphically and in the detail window, but it is not displayed in the main status area. Like the Actual Speed, this parameter is calculated. However, instead of being calculated off of Transducer Counts, it is calculated from the Target Position. Therefore, when viewing a plot you can compare the Actual and Target Speeds to determine how well the actual move is tracking the intended move.
Why is the Target Speed Jagged During Constant Velocity?
With older versions of the RMC100 CPU firmware and RMCWin, you may notice that during some constant velocity moves, the Target Speed is not flat. The jaggedness is caused by quantizing. That is, suppose that at constant velocity the axis is moving an average of 4.2 position units per millisecond. Because the motion controller only reads whole numbers of position units, the Target Position would appear to increase by 4 position units for four milliseconds, and every fifth millisecond it would move 5 position units. Therefore, if we were to calculate the speed based on a single interval, the speed would vary by 25% every fifth interval.
When the Target Speed is calculated, smoothing is performed so it does not vary by such a large amount, but some jaggedness is left from rounded-off position units.
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