Rockwell Automation 1336T Function Block Prog. Manual, Series A/B - Manual (Page 103)

Function Block Library 4–41
1336 FORCE — 5.9 August 1995
Example 3 — KI & KP = 1 — Horizontal Scale = 500 mS/Division
In Example 3, all gains are at unity — KI and KP are set to 4096, Gain is set to 2048.
A PI CTRL Output
+ 32767 "
– 32767 "
PI CTRL Input
B
0 "
A–– 1 Second –"
+ 16383 "
– 16383 "
A PI CTRL Output
The input difference in this example alternates between
±
16383. The proportional Output
response immediately jumps to 0. The Output takes one second to accumulate to + 16383
and two seconds to move from – 32767 to + 32767.
A–––––––––– 2 Seconds ––––––––––"
Example 4 — KP = 1, KI = 2 — Horizontal Scale = 500 mS/Division
Example 4 is similar to Example 3, except that the KI gain is now at 8192, or 2
×
the value in
Example 3. KP gain is set to unity (4096), and Gain is set to unity (2048).
+ 32767 "
– 32767 "
– 16383 "
0 "
Y
PI CTRL Output
+ 16383 "
PI CTRL Input
B
The Output reaches 16383 within 500 mS and + 32767 within one second. In this Example,
the Output is clamped at the positive and negative limits. The internal accumulator is also
clamped at these limits, and cannot accumulate beyond these limits. This allows the PI
CTRL function to immediately get out of saturation when the function’s input difference
changes polarity.
" 500 mS A
Y
PI CTRL Output
A–– 1 Second ––"
PI CTRL
(continued)