Rockwell Automation Allen-Bradley PowerFlex 520 Series, User Manual, Page: 218 / 272

218 Rockwell Automation Publication 520-UM001K-EN-E - August 2021
Appendix E Encoder/Pulse Train Usage and Position StepLogic Application
HTL/TTL DIP Switches
This feature is available on 25-ENC-1 encoder. Set the two switches to HTL
(default) or TTL (On) based on the type of encoder signal you are using in your
application. You must set all switches to the same position.
+V Cm B- B A- A
12V 5V
n
HTL TTL (ON)
No. Signal Description
+V
5...12V Power
(1)(2)
(1) When using 12V Encoder power, 24V I/O power, maximum output current at I/O Terminal 11 is 50 mA.
(2) If Encoder requires 24V power, it must be supplied by an external power source.
Internal power source 250 mA (isolated).
Cm Power Return
B- Encoder B (NOT)
Quadrature B input.
B Encoder B
A- Encoder A (NOT)
Single channel, pulse train or quadrature A input.
A Encoder A

Output
DIP switch selects 12 or 5 volt power supplied at terminals “+V” and “Cm” for
the encoder.

HTL/TTL DIP
switches
Set the position of the DIP switches based on the type of encoder signal used.
You must set all switches to the same position.
Encoder Wiring Examples
I/O Connection Example I/O Connection Example
Encoder Power
– Internal Drive
Power
Internal (drive)
12V DC, 250 mA
Encoder Power
– External
Power Source
Encoder Signal
– Single-Ended,
Dual Channel
Encoder Signal
– Differential,
Dual Channel
Compatible Encoder Output Voltage
Switch Position Low Level (UL) High Level (UH)
TTL <1.5V >2.5V
HTL <3.5V >5V
IMPORTANT
Only the 25-ENC-1 Encoder will work properly in the PowerFlex 525 drive. Installing
an incorrect encoder card, such as the PowerFlex 527
25-ENC-2 will cause damage to the PowerFlex 525 drive.
Common
+12V DC
(250 mA)
A
A-
B
B-
Cm
+V
to SHLD
+
Common
External
Power
Supply
to
SHLD
A NOT
A
B
B NOT
to SHLD
to Power Supply
Common
A
A-
B
B-
Cm
+V
to SHLD
A NOT
B
A
B NOT
A
A-
B
B-
Cm
+V