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Glossary
absolute position
A position given in respect to the origin rather than in respect to the present
position.
attribute
One of several types of data that define positioning actions. Attributes include
settings such as interpolation code, interpolation point, and completion code.
backlash compensation
Compensation for the amount of mechanical play, or “looseness,” present in
gears. Such play can create positioning inaccuracy when the direction of
positioning changes.
BCD
An acronym for binary-coded decimal. This is used to code decimal numbers in
binary.
circular arc center
An interpolation point which can be defined, along with the interpolation end
point, to enable circular arc interpolation. Taking these points as known values,
the Position Control Unit can position in a circular arc pattern.
An interpolation point which can be defined, along with the interpolation end
point, to enable circular arc interpolation. Taking these points as known val-
ues, the Position Control Unit can position in a circular arc pattern.
circular arc interpolation
Dual-axis positioning in a circular pattern from the present position to a point
designated as the interpolation end point. In addition to the interpolation end
point, it is necessary to designate either a circular arc center or a circular arc
intermediate point.
completion code
A positioning action attribute that determines, upon completion of a given
positioning action, whether positioning stops or whether the next positioning
action is executed immediately, without a break.
continuous (completion)
The completion code that causes the next positioning action to be executed
immediately upon completion of the current one.
CW and CCW
Abbreviations for clockwise (CW) and counterclockwise (CCW). CW and CCW
are defined for a motor shaft in reference to a viewer facing the shaft on the end
of the motor from which the shaft extends from the motor for connection.
CW/CCW limits
Limits on the CW and CCW sides of the origin which can be internally set to
restrict rotation of the shaft.
data area
A memory storage area in the PC. Different types of memory blocks, with
differing functions, are stored in the various data areas of the PC. These blocks
of memory are built up from single units, or bits, which are grouped into 16-bit
words. Commands used to control the Position Control Unit are transferred from
a data area in the PC.
distributed control
An automation concept in which each portion of an automated system is located
near the devices actually being controlled. In other words, control is
decentralized and “distributed” over the system. Distributed control is a concept
basic to PC systems.
DM area
A PC data area in which general operating parameters, speeds, and positions
for positioning actions are stored.
dwell time
A setting that specifies the period of time during which positioning will stop
before execution of the next positioning action.
error code
A four-digit code which is output to the PC and the External Display to identify the
type of error which has occurred.
error counter
A device used to ensure positioning accuracy when positioning via pulse trains.
The error counter receives a target position as a specific number of pulses in a
pulse train from the Position Control Unit and outputs analog speed voltages to
drive a servomotor accordingly. The specified number of pulses in the error
counter is counted down by feedback from an encoder measuring actual motor
shaft movement, causing voltage output to stop when the number of pulses
equals zero, i.e., when the target position has been reached.
external interrupt
A function whereby positioning may be stopped or speed may be changed,
during operation, in response to an external signal.
feedback
The return of a portion of the output of a circuit or device to its input. It is used in
servocontrol systems to help bring actual values closer to target values.
circular arc intermediate
point