2 ramp function generator, 3 operating range of the pid process controller, 2 ramp function generator 3 – Lenze 8400 User Manual

Page 1363: 3 operating range of the pid process controller 3, 18 function library

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Lenze · 8400 protec HighLine · Reference manual · DMS 3.0 EN · 03/2013 · TD05

1363

18

Function library

18.1

Function blocks | L_PCTRL_1

_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _

18.1.133.2 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.

[18-54] 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.

C00227

: Acceleration time t

ir

C00228

: 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.

18.1.133.3 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:

C00231/1

: Pos. maximum (default setting: 199.99 %)

C00231/2

: Pos. minimum (default setting: 0.00 %)

C00231/3

: Neg. minimum (default setting: 0.00 %)

C00231/4

: Neg. maximum (default setting: 199.99 %)

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

-----------------------

=

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