Encoder Inputs - Danaher Motion Standalone MMC Hardware Manual

Danaher Motion
current. The voltage is in series with the DC power supply. The combined voltage
appears across the output switching device in the module.
If this were the only path available, voltage across the device would peak at several
hundred volts. The internal diode provides another path for current. This limits the
peak reverse voltage across the load to less than 1 V. Every DC output has this
protection so an inductive load can be connected safely.
Figure A-2: Diagram of Internal Protection for Inductive Loads
DC Power Supply
0V
V+
MMC POWER
CONNECTOR
INDUCTIVE
LOAD
DCOUT1
a) Output Energized
A.4

Encoder Inputs

The encoder inputs use differential type inputs to interface with incremental encoders.
These inputs accept RS422 level quadrature signals. Recommended encoder drivers
include 7272, 75183, 8830, 75114, 9614, 26LS31 (or equivalent).
A quadrature encoder sends square wave type signals. When the shaft rotates at a
constant velocity, the A and B outputs are square waves and are at the same
frequency. However they are out of phase with each other by 90°. When the encoder
shaft rotates in one direction, each A pulse leads the corresponding B pulse by 90°.
When it rotates the other direction each A pulse lags its B pulse by 90°.
The signals illustrated in
one direction at first. Its speed of rotation decreases to 0 and then it starts rotating the
other direction. The signals are shown as differential. A is the inverse of the signal A
and B is the inverse of signal B.
Standalone MMC Hardware Manual
version 15.1
DC Output
Output
Switching
Device
Figure A-3
DC Power Supply
0V
V+
MMC POWER
CONNECTOR
INDUCTIVE
LOAD
DCOUT1
b) Output De-energized
below indicate that the encoder shaft rotates in
Operation Details
DC Output
Output
Switching
Device
175