Quadrature Modes Of Counting; Quadrature Mode Overview; Quadrature Counting Mode; Figure 1-4 1X Quadrature Mode - Siemens SIMATIC TI505 User Manual

1.3

Quadrature Modes of Counting

Quadrature Mode
Overview
1X Quadrature
Counting Mode
High Speed Counter Encoder Module User Manual
Each 24-bit counter, Counter 1 (Channel 1, inputs A & B) and Counter 4
(Channel 2, inputs A & B) provides Quadrature mode counting. When input
A pulses lead input B pulses, the count direction is up. When input B pulses
lead input A pulses, the count direction is down. The relationship between
input A and input B that determines the count direction applies to 1X, 2X,
and 4X Quadrature counting modes, described in this section.
For information on how to configure the module for quadrature counting,
refer to Chapter 5.
You select one of the three quadrature modes according to the resolution
required by your application and the type of encoder you are using.
When set to 1X Quadrature Mode, the module counts the rising or the
falling edges of input A pulses, depending on the count direction.
When input A leads input B, the count direction is up and the count
value increments on each rising edge of input A.
When input B leads input A, the count direction is down and the count
value decrements on each falling edge of input A.
Figure 1-4 shows the relationship between inputs A and B, and the count
value that results using 1X quadrature mode.
Counts rising edge of input A
Count Value: 1
Encoder Pulses
A
B
Pulse A leads: Count Up

Figure 1-4 1X Quadrature Mode

2
Pulse B leads: Count Down
Counts falling edge of input A
1 0
Product Overview 1-7