Performance Motion Devices PR8358120 User Manual Download Page 53

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Operation

Prodigy/CME PC/104 User’s Guide

The encoder-processing circuitry provides a multi-stage digital filter of the

QuadA, QuadB

, and

Index

signals for each

axis. This provides additional protection against erroneous noise spikes, thus improving reliability and motion
integrity. These signals are named

through

QuadB4

(16 signals), and

through

Index4-

(8 signals).

2.7.2.1

Connections & associated signals

These signals can be connected in one of two ways. Single-ended means that only one wire per signal is used, while
differential means two wires encode each signal (l and -). Differential transmission is generally recommended
for the highest level of reliability, because it provides greater noise immunity than a single-ended connection scheme.

If single-ended connections are used, only the + signal is connected, and the - signal should be left floating. For example,
in connecting to the A quadrature input,

connects to the signal, and

QuadA1-

remains floating. If differential

connections are used, both the + and - signals are used. Differential or single-ended termination must be selected
through resistor pack installation. See the table in Section

1.8, “Preparing the Card for Installation,” on page

14 for

details.

When using the system with differential connections, the polarity of the differential signal can be reversed by swapping
the + and - connections. This may be useful for altering the motor and/or encoder direction; however, this same
function can also be accomplished through commands to the Prodigy/CME PC/104 card. See the

Magellan Motion

Processor User’s Guide

for more information. Associated connections supported by the card are the +5V output signals.

These are provided as a convenience, as they are generally connected to a corresponding input on the encoder to power
its internal circuitry. As was the case for the digital input signals, one or more of the digital grounds must also be
connected.

See Chapter

Electrical Reference

, on page

69 for a complete description of the pinout connections to and from the

card.

2.7.3

Analog Input

The

Analog1-8

signals provide general purpose input of up to eight analog signals. The voltages present at these various

connections do not directly affect the Prodigy/CME PC/104 card’s behavior. However, they can be read through the
Prodigy/CME PC/104 card, thus providing a convenient way of importing analog signal levels which may be acted
upon by the user’s application code located on the host PC. These signals are read using the Magellan command

ReadAnalog

. For more information on reading the value of these analog inputs, see the

Magellan Motion Processor User’s

Guide.

The minimum allowed input voltage is 0.0V, and the maximum allowed input voltage is 3.3V. To determine the

numerical value that will be read by the Prodigy/CME PC/104 card given a specific voltage, the following formula is
used:

ReadValue = AnalogVoltage * 65,536 / 3.3V

Conversely, given a read value, the voltage at the connection is calculated as:

AnalogVoltage = ReadValue * 3.3V / 65,536

2.7.3.1

Connections & associated signals

For analog voltages to be read correctly, in addition to the analog signal itself,

AnalogGND

(analog ground) must be

connected.

2.7.4

Pulse and Direction

For pulse & direction applications, these signals provide a stream of pulse and direction data, and are compatible with
a wide variety of off-the-shelf step motor amplifiers. These signals are generated by the Magellan Motion Processor
and are named

Pulse1-4

and

Direction1-4

. The default value at power-up and reset for all pulse and direction output

signals is: pulse signal is high; direction signal is low.