Rockwell Automation 1771-QA Stepper Positioning Assembly User Manual User Manual

Page 15

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2–5

Assembly and Installation

Publication 1771-UM002A–EN–P – May 2000

4. Set the switches as described in the following sections. Some

switches are labeled on/off. Others may be labeled open for the
off position.

5. Reassemble the module. Start all four screws before tightening to

facilitate alignment of the covers and printed circuit board.

Output Format (S1)

The output format that determines forward or reverse motion differs
between translators. Therefore, the output terminals of the pulse
expander module are user-selectable to match the required pulse
input configuration of the translator. There are two basic translator
input configurations.

Some translators are designed to receive a pulse train at either one of
two terminals, depending on the direction of rotation desired in the
stepping motor. With this type of translator, a pulse train sent from
the pulse output expander module to one of the translator terminals
causes the stepping motor to rotate in the forward direction. An
identical pulse train sent from the module to the other translator
terminal causes the stepping motor to rotate in the reverse direction.
Output terminals on the pulse output expander module can be
selected in accordance with Table 2.B.

Table 2.B
Output Format (S1)

Switch Assembly S1

Switch 1 Switch 2

Output

Terminal

Active Output

Configurations &

Logic Levels

Logic

Level

When

Stopped

either ON

or OFF

OFF

10

11

12

High
Forward Pulse train
Reverse Pulse train

High
High
High

OFF

ON

10

11

12

Pulse train
Low

High

(Forward)

(Reverse)

High

Low

High
Last State

Last State

ON

ON

10

11

12

Pulse train
Low

High

(Forward)

(Reverse)

High

Low

High
High

High

Note: Low = true logic

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