16
Publication 1746-5.16
Single-Ended Encoder Wiring (Open Collector)
VS Value
R Value
Maximum Output Leakage
+5V dc
150 ohm 1/4W 5%
6.3 mA
+12V dc
1800 ohm 1/4W 5%
1.5 mA
+24V dc
4700 ohm 1/4W 5%
1.2 mA
A
B
Z
A(+)
A(±)
B(+)
B(±)
Z(+)
Z(±)
R
1234
Belden 9503 or equivalent
305m (1000tft) max length
Power
Supply
+ VDC
COM
VS
GND
Allen-Bradley
845H Series
single-ended
encoder
encoder connector
housing
Earth
Shield
(2)
Module Inputs
SW1
ON
OFF
(All switches OFF)
cable
(1)
(1) Refer to your encoder manual for proper cable type and length.
(2) Due to the topology of the module’s input circuits, terminating the shield at the encoder end
provides the highest immunity to EMI interference. Connect EARTH ground directly to the
encoder connector housing.
(3) The pullup resistor (R) value depends on the power supply value (VS). The table below lists
the resistor values for typical power supply values. These resistors must be located at the
encoder end of the cable.
(3)
A
B
Z
The figure below shows the single-ended encoder output waveforms. When the waveform is low,
the encoder output transistor is ON.
low = transistor ON
high = transistor OFF
Single-Ended Encoder Output Waveforms