8400 BaseLine D | Software Manual
Function library
Function blocks
158
L
Firmware 03.00 - DMS EN 5.0 - 07/2009
9.1.3.2
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.
[9.5]
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.
– Acceleration time t
ir
– 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.
9.1.3.3
Value range of the output signal
The output signal and thus the operating range of the PID-component can be limited
with the parameters nMaxLimit and nMinLmit (- 199.9%...+ 199.9%)
9.1.3.4
Evaluation of the output signal
The limitation is followed by an evaluation of the output signal via
nInfluence_a
.
This evaluation is activated or suppressed along a ramp via the input
bEnableInfluenceRamp
. The ramp times are set with the parameters "Influence
acceleration time" and "Influence deceleration time" (C00243 / C00244).
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
if
T
ir
T
if
T
ir
t
ir
100 %
w2 w1
–
----------------------
⋅
=
T
if
t
if
100 %
w2 w1
–
----------------------
⋅
=