MAN0974-14-EN_XL7_XL7P_UM
July 6, 2022
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9.2
Glossary
Table 9.1
–
Glossary of High Speed I/O Terms
Accumulator
Register used to accumulate or store up a sum or count of many items or events.
Clear
A special function to zero out the value in a specific register. (Not used with Frequency
or Period Measurement.)
Disable
A special function to prevent the counter from running.
Encoder
A sensor or transducer for converting rotary motion or position to a series of
electronic pulses
FPGA
An integrated, configurable circuit that allows the controller to be programmed to
have either two high-speed counters or four high-speed counters.
Frequency
Input
The number of times an electromagnetic signal repeats an identical cycle in a unit of
time, usually one second.
Latch
(strobe)
A special function that uses a digital logic circuit to store one or more bits. A latch has
a data input, a clock input and an output. When the clock input is active, data on the
input is "latched" or stored and transferred to the output register either immediately
or when the clock input goes inactive. The output retains its value until the clock goes
active again.
Marker
Input into the OCS that indicates a particular position. Typically, an encoder has a
marker output that represents a specific point in the rotation.
Polarity
A Polarity pull-down box is associated with each function and indicates the manner in
which the trigger happens (e.g., High level, Low Level, Falling Edge, Rising Edge).
Preload
(load)
A special function used to trigger loading of a value into a register upon an event. (Not
used with Frequency or Period Measurement.)
Quadrature
A high-speed device that expresses the phase relationship between two periodic
quantities of the same period when the phase difference between them is one fourth
of a period. A coupler in which the two output signals are 90° out of phase.
Totalizer
A counter that sums the total number of cycles applied to its input.
