Rockwell Automation 1771-QC , D17716.5.25 SER/B SERVO POS User Manual

Page 119

Advertising
background image

Formatting and Interpreting Data Blocks

Chapter 7

7Ć37

Figure 7.26

Backlash Takeup Word

17 16 15 14 13 12 11 10 07 06 05 04 03 02 01 00

Backlash Takeup Distance

Word 23 (Axis 1)

Word 42 (Axis 2)

Word 61 (Axis 3)

inch

metric

Distance axis overshoots when initial

approach to endpoint is from direction

opposite that specified in bit 17.

11048

Sign:

0 = +

1 = -

Axis approaches all

endpoints moving in the

direction specified by

the sign (bit 17).

decimal

point

decimal

point

In this word, bit 17 specifies the direction the axis is to move in
approaching all programmed endpoints. When the axis approaches an
endpoint at which it is to stop while moving in the specified direction, it
simply stops at the endpoint. If the axis approaches the endpoint from the
opposite direction,it overshoots the endpoint by the amount you specify in
bits 00 thru 16, then returns to the endpoint from the opposite direction.

Consider the example of your entering +.0010 in the backlash takeup
word:

If the axis is moving in the positive direction it stops at the

programmed endpoint without overshoot.

If the axis is moving in the negative direction, it overshoots the

endpoint by 0.001 inch, then returns to the programmed endpoint.

Backlash takeup affects only halt moves that command the axis to stop at
a move endpoint. For blended moves, backlash takeup has no effect.
Also, backlash takeup is active only in auto mode. Backlash takeup has
no effect on axis motion in the manual mode.

This parameter has a 4-digit BCD value in the range of 0.0001 to 0.7999
inches or 0.001 to 7.999 mm.

Offset

Word 24 (43, 62) specifies the value the servo positioning assembly adds
to the offset accumulator when the servo positioning assembly executes
one of the following:

Advertising