Delta MMC120 - Manual (Page 74)

Glossary MMC120 Linear Motion Control Module
74 Delta Computer Systems, Inc. 360/254-8688
GLOSSARY OF TERMS
Actual Position - The scaled measured axis position expressed in Position Units.
Circulation - The process of sending an interrogation signal to a transducer and counting a high frequency
clock while waiting for the transducer to respond.
Cleared - Refers to a FALSE or logic zero value.
Counts - Raw number of digital counts for a given physical distance. The number has NOT been scaled to
represent the actual physical distance.
Extending - Moving or turning the axis such that the transducer counts increase.
Feed Forward - Control industry term used to express the amount of output drive needed to reach a desired
speed, or the open loop gain of a control system.
MCM - Motion Control Module.
Overlap - Overlap is a region in a hydraulic valve where no fluid can flow in either direction; it is usually
specified in percent. Valves with large overlap are very difficult to control.
PID - Control industry term used for Proportional, Integral, and Differential drive compensation.
Position Unit - Basic unit of distance measurement for a specific application (i.e., thousandths of an inch,
tenths of millimeters, thousandths of revolutions, etc.). Position units are calculated using the SCALE
and COUNTS parameters.
Retracting - Moving or turning the axis such that the transducer counts decrease.
Scale - A multiplier used to translate Transducer Counts to Position Units. It can also be used to
compensation for differences in magnetostrictive transducers.
Set - When referring to STATUS bits it refers to a TRUE or logic one value. It also refers to a physical
positions of the axes.
Target Position- A calculated position at which an axis is expected to be at any given time.
Transducer - A general term for a device that converts a physical distance to an electrical signal.
Transducer Counts - See Counts.