Brodersen UDC-35 Bedienungsanleitung Seite 32

32 - UDC-35 Digital Panel Controller
Proportional Period.
The period for the pulse width control circuit
can be adjusted to adapt actual process
requirement.
Minimum Time for Activated Output.
In systems using contactors or other electro-
mechanical devices, the lifetime of these
can be prolonged by suppressing action
which is shorter than selected with the "Act"
parameter.
Pv
Sp
Out-
put
T
P.PEr
Input Delay.
An input delay with adjustable time cons-
tant can be defined to suppress noise on
the input signal.
7. AUTOTUNING.
The UDC-35 regulator is equipped with an
autotune facility which may help to find us-
able PID-parameters.
The regulator requirements very much de-
pend on the actual application and process
conditions. A compromise between start-
uptime and e.g. accepted overshoot is often
required.
The autotune facility may not always find the
optimum parameters but in that case the
parameters can be manually adjusted until
the best combination is obtained.
The UDC-35 autotune facility estimates the
parameter from a number of loop measure-
T
_Act
ments.
t
Before performing an autotune cycle the
proportional period must be selected ma-
nually.
As the regulator is NOT able to operate
normally during the autotune period, the
process value may exceed values (over-
shoot/undershoot) which in some proces-
ses are unacceptable.
In such processes the autotune facility must
be omitted or the necessary precautions
must be taken prior to activation.
Typical autotune cycle.
Pv
Sp
Loop natural
frequency and
over/undershoot
Depending on the actual time constants in
the loop, the autotune cycle may take from
few minutes to several hours (max. 3 hours).
Operation
Loop Loop
load response