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Figure 5 - single-ended encoder wiring, Vdc vmin – Rockwell Automation 1769-HSC Compact High Speed Counter Module User Manual

Page 15

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Compact I/O High-speed Counter Module 15

Publication 1769-IN030B-EN-P - October 2010

Figure 5 - Single-Ended Encoder Wiring

(1)

Refer to your encoder manual for proper cable type. The type of cable used should be twisted-pair, individually shielded
cable with a maximum length of 300 m (1000 ft).

(2)

External resistors are required if they are not internal to the encoder. The pull-up resistor (R) value depends on the power
supply value. The table shows the maximum resistor values for typical supply voltages. To calculate the maximum resistor
value, use the following formula:

where:

R = maximum pull-up resistor value

V DC = power supply voltage

V min = 2.6V DC

I min = 6.8 mA

The minimum resistor (R) value depends on the current sinking capability of the encoder. Refer
to your encoder’s documentation.

Power Supply Voltage (V DC)

Pull-up Resistor Value (R), Max

(1)

(1)

Resistance values may change, depending upon your application.

5V DC

352

Ω

12V DC

1382

Ω

24V DC

3147

Ω

A

B

Z

A1(+)

A1(–)

B1(+)

B1(–)

Z1(+)

Z1(–)

GND

VS

+VDC

COM

R

(2)

Cable

(1)

Power
Supply

Allen-Bradley
845H Series
Single-ended
Encoder

Shield/Housing
Connect only if housing is electronically
isolated from the motor and ground.

Shield

Module Inputs

Earth

R

VDC Vmin

Imin

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