Glossary
© National Instruments Corporation G-5 NI 7340 User Manual
Hhalf-step mode of a stepper motor—for a two phase motor this is done by alternately 
energizing two windings and then only one. In half step mode, alternate 
steps are strong and weak but there is significant improvement in low-speed 
smoothness over the full-step mode.
hex hexadecimal
home switch (input) physical position determined by the mechanical system or designer as the 
reference location for system initialization. Frequently, the home position is 
also regarded as the zero position in an absolute position frame of reference.
host computer computer into which the motion control board is plugged
II/O input/output—the transfer of data to and from a computer system involving 
communications channels, operator interface devices, and/or motion 
control interfaces
ID identification
in. inches
index marker between consecutive encoder revolutions
inverting polarity of a switch (limit switch, home switch, and so on) in active state. 
If these switches are active-low they are said to have inverting polarity.
IRQ interrupt request
Kk kilo—the standard metric prefix for 1,000, or 103, used with units of 
measure such as volts, hertz, and meters
K kilo—the prefix for 1,024, or 210, used with B in quantifying data or 
computer memory