Rockwell-automation 1734-IK Encoder/Counter Modules User Manual Manuel d'utilisateur télécharger pdf (Page 13)

Publication 1734-UM006B-EN-P - August 2005

About the Modules 1-3

Example of Counter Mode

Encoder Mode

The encoder mode reads incoming pulses and returns a binary

number (0 - 16,777,215

max

) to the POINTBus. The encoder mode

only accepts 2 phase quadrature inputs. The module senses the

relationship between the 2 phases, and counts up or down

accordingly.

The two basic encoder types are absolute and incremental. A single

output incremental encoder is called a tachometer encoder. A dual

channel incremental encoder with one channel leading the other by

90° is called a quadrature encoder.

A system using a quadrature encoder may include an optional zero

pulse, or index, serving as a reference mark for system reset. The

principal disadvantage of a system using incremental encoders is that

a power interruption causes the loss of position reference, so a system

must be reinitialized or returned to a known zero position.

Absolute encoders typically have higher speed requirements (200 KHz

typical) for motion control applications. An absolute encoder has a

unique code associated with each position, so the exact position is

always known, even if the system power is turned off.

A Input

B Direction

Z (Store Count)

ingle Phase Pulse Generator

1734-VHSC

Input A

Input B

123

Input

ount

(Gate / Reset )

210

Count Up Count Down

Input Z

Outputs

Updated

Continuously

1 2 ... 8 9 10 11 12 13 14 15 16 17 18 ... 67 68

Pas de commentaire

Rockwell-automation 1734-IK Encoder/Counter Modules User Manual Manuel d'utilisateur Page 13