Rockwell-automation 1756-HSC ControlLogix High Speed Counter Module Manual de usuario descargar pdf (Pagina 21)

Rockwell Automation Publication 1756-UM007C-EN-P - November 2011

Counter Modes 21

Encoder x4

Encoder x4 mode is identical to x1, except this mode counts on the leading

and trailing edges of A and B to provide a greater number of pulse counts. The

greater the number of pulse counts the better the module can

determine position.

Input Z is used in Encoder mode only if a Store Count mode is enabled.

See

page 23

for details on the storage modes.

Encoder x4 Mode

Maximum frequency in Encoder x1 and x4 modes = 250 kHz (assuming

50% duty cycle), with a minimum pulse width at this frequency of 2 s. The

module assumes a 90° phase (A/B°) difference between channels.

Input A

Quadrature Encoder

1756-HSC Module

Input B

Input A

Input B

Input A

Input B

B Leads A 90° A Leads B 90°

1 2 3 4 5 6 7 8 9 10 11 12 1234567891011 0

41689

Accumulated Count

in Present Value Tag

Directional Frequency

in Totalizer Tag

Positive Frequency Negative Frequency

Input Z (optional)

1 2 ... 16 17 18 19 20 21 22 23 24 25 26 ... 127 128

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Rockwell-automation 1756-HSC ControlLogix High Speed Counter Module Manual de usuario Pagina 21