Siemens SIMATIC 505 User Manual

Overview

Series 505 High Speed Counter

 and Encoder Module User

’s Manual

For quadrature mode, each channel counts according to rising and/or



falling edges. Typical devices for quadrature inputs are optical encoders.
Different quadrature modes are selected based on the resolution required
by the application and the encoder used.

The module counts on the edges of the A input pulses. 

 When input A leads input B, the HSC counts up on each rising edge of

input A.

 When input B leads input A, the HSC counts down on the falling edge

of input A.

Figure 1-5 illustrates the relationship between inputs A and B and the
count value in 1X Quadrature mode.

Count Value

1

2

1

0

A

B

25



s

 min

Count Up

(A Leading)

Count Down

(B Leading)

26.7 



s

min