Rockwell Automation 1771-QB Linear Pos. - Manual (Page 100)

Formatting Module Data (WRITES)
Chapter 7
7Ć21
Figure 7.27
Gain Factor Word
50070
Gain factor,
BCD or binary
0.00 to 9.99
15 14 13 12 11 10 09 08 07 06 05 04 03 02 01 00
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The gain factor must be less than 10.0. If you set it to zero, the proportional gain
won’t be reduced or increased at any axis speed.
Example: To increase a proportional gain to 0.5 from 0.1 at speeds above the
gain break speed:
gain factor = desired gain/proportional gain
= 0.5/0.1
= 5.00
Integral Gain (words 20 and 49)
The integral gain factor K
I
is used by the integral component during final axis
positioning, i.e., when the desired velocity is zero and the axis is in the PID
band.
Figure 7.28
Integral Gain Word
50071
Integral gain,
BCD or binary
0.9999 (ips/s) /mil or 0.9999 (mmps/s) /mil
(1 mil = 0.001 inch or 0.001 millimeter.)
15 14 13 12 11 10 09 08 07 06 05 04 03 02 01 00
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The module uses integral control to improve final positioning accuracy by
making the system sensitive to the duration of positioning errors. If a
positioning error exists, the integral term continues to alter the analog output
until the axis overcomes inertia and reaches an accurate position.