Flexible Encoder Source Average RPM Derivative

Recovers the Average RPM derivative of the referenced encoder source.

Block ID

Get Average RPM Derivative for Source

Library

motohawk_flexenc_lib

Description

Average RPM

On each RPM sample point a sum of periods is captured that can be used to calculate average RPM and cycle RPM. Say, for example, RPM sample points have been associated with a system's TDCs and that these happen to result in the regions illustrated by the figure below. Requesting the average RPM just after TDC#1 had occurred would result in an RPM that was based upon the blue period being returned. Requesting the average RPM just after TDC#2 had occurred would result in an RPM that was based upon the light blue period being returned and so forth.

Average RPM Derivative (dRPM/dT) Output Port

The derivative (RPM/sec) is calculated as the delta Average RPM divided by the period of the last completed region. Say an application requests the RPM derivative at the instant where the encoder position is somewhere within the cyan region. The last completed region is the light blue region and the previous region is the blue region. The derivative returned while the encoder position resides within the cyan region will use RPM averages from the light blue and blue regions to calculate the delta and will use the light blue time to determine the dT component.

Index (Idx) Output Port

The (zero based) index indicates what dT region was used to calculate the deriviative. An index value of zero would be returned when the blue region provided the dT, an index of one for the light blue region and so forth.

Valid Output Port

There are times, such as when first starting up, or if an encoder synchronization error has been observed, where a derivative is not available. The Valid port can be used to ratify whether the returned derivative value is a valid derivative.

Block Parameters

Parameter Field	Values	Comments/Description
Reference Absolute Source Name	Alpha-numeric text, quote enclosed	Recover the derivative from this named absolute source.