User guide

11 Function library
11.3 L_PCTRL_1
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Lenze · 8400 BaseLine C · Reference manual · DMS 1.6 EN · 01/2014 · TD05
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11.3.2 Ramp function generator
The PID output is led via a ramp function generator with linear characteristic. This serves to transfer
setpoint step-changes at the PID output into a ramp which should be as steep as possible.
[11-4] Acceleration and deceleration times
•t
ir
and t
if
are the desired times for changing between w1 and w2.
• The ramps for acceleration and deceleration can be set individually.
• C227
: Acceleration time T
ir
• C228
: Deceleration time T
if
•The t
ir
/t
if
values are converted into the required Ti times according to the following formula:
• The ramp function generator is immediately set to "0" by setting bInAct to TRUE.
11.3.3 Operating range of the PID process controller
The value range of the input signal nSet_a and thus the operating range of the PID process controller
can be limited with the following parameters:
• C231/1
: Pos. maximum (default setting: 199.9 %)
• C231/2
: Pos. minimum (default setting: 0.0 %)
• C231/3
: Neg. minimum (default setting: 0.0 %)
• C231/4
: Neg. maximum (default setting: 199.9 %)
11.3.4 Evaluation of the output signal
After the limitation, the output signal is evaluated with the influencing factor nInflu_a. The evalu-
ation is activated/suppressed along a ramp when the input bEnableInfluenceRamp is set to TRUE.
The ramp times are set with the parameters "Acceleration time influence" (C243
) and "Deceleration
time influence" (C244
).
w1, w2 = change of the main setpoint as a function of t
ir
and t
if
RFG-OUT = output of the ramp function generator
RFG-OUT
100 %
w2
w1
t
0%
t
ir
t
ir
T
ir
T
ir
T
ir
t
ir
100 %
w2 w1–
-----------------------
⋅=
T
if
t
if
100 %
w2 w1–
-----------------------
⋅=