Horner APG XL7 OCS - Manual (Page 44)

XL7 User Manual
CHAPTER 11: HIGH SPEED I/O (HSC / PWM)
11.1 Overview
In addition to the compliment of simple analog and digital I/O, several of the XL7 OCS I/O modules
support High Speed Counting (HSC) I/O functions and may also support Pulse Width Modulation (PWM)
Output functions (non-relay modules). The HSC functions include: internal timing, frequency, totalizing,
pulse width/period and quadrature measurement. The PWM functions include: traditional PWM (with
variable rate and duty cycle) and a stepper (limited functionality) with variable acceleration and
deceleration rates. To determine function availability, refer to the associated model’s
Specification/Installation sheet (Digital DC Input / Output sections.)
This chapter describes the operation of these high level I/O functions. For configuration details of these
functions, see Cscape Configuration.
11.2 Glossary
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
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.
Table 11.1 – Glossary of High Speed I/O Terms
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