Dynisco ATC770, Инструкция по установке и эксплуатации

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ATC770 Microprocessor-Based Pressure/Process Controller 49
7.3.1 S
ELECTING THE
T
YPE OF
C
ONTROL
There are two types of control mechanisms that the ATC770 can use, either
PID (Proportional,
Integral, and Derivative), or PI (Proportional and Integral). The default value is
PI, since a majority of
the applications are extrusion motor control. To verify the Control Type, press the
FUNC
key until
nonE and GROUP show on the display. Press the
▲
key until 2 shows in the upper display. Press the
FUNC
key until the lower display shows AT.TYP. The upper display will show PI. If desired, press
the
▼
or
▲
key until the upper display changes to
Pid. Press the
FUNC key to set the value.
7.3.2 E
NGAGING THE
T
UNING
A
LGORITHM
(ATC770
IN
M
ANUAL
M
ODE
)
Ensure that the
MAN LED on the face of the ATC770 is illuminated. If so, press the
FUNC key until
nonE and GROUP show on the display. Press the
▲
key until
2 shows in the upper display. Press the
FUNC
key until the upper display shows OFF and the lower display shows SMART. Press the
▼
or
▲
key until the upper display changes to ON. Press the
FUNC
key to set the value. This will activate
the Tuning Algorithm, and will switch the SMART function to OFF after the PID parameters are
calculated. As the calculations occur, the LED will be flashing.
Mathematically, the model of the process can be characterized using three parameters: the gain, the
time constant, and the equivalent time delay. To determine these parameters, the power output of the
controller is changed by a small step value. Then, the controller stores the process variable response.
From this response, the controller estimates the three process parameters. It then applies these
parameters, and re-runs the step process. When this is done, it calculates the final PID parameters.
During the tuning process, the calculated parameters can be viewed as they are determined and the
system’s response to the parameters evaluated. The parameters available to view are the Time of
Smart Function,
(RLTM), the Step for Smart Function, (AT.STP), the Proportional Band (PB), the
Integral Time (TI), and the Derivative Time (TD).
7.3.3 V
IEWING THE
T
UNING
A
LGORITHM
P
ARAMETERS
Press the
FUNC
key until nonE and GROUP appears. Press the
▲
key until 2 shows in the upper
display. Press the
FUNC
key until the lower display shows RLTM. The upper display shows the filter
time constant selected by the algorithm. During the process analysis, the upper display shows the
elapsed time from the step change in mmm.ss format (minutes and seconds). The maximum value is
500 minutes. More than that will disable the SMART function.
The value of the step change used by the SMART (TUNE) process is displayed after the RLTM
parameter. After viewing the RLTM parameter, press the
FUNC
key to see the AT.STP parameter
value. The expected range is from -25.0% to 25.0% of full scale. The default value is 10.0%.
Also available are the following parameters:
• The proportional band parameter
(PB) follows the AT.STP parameter. Its range is 1 to 10.000%
and changes to this parameter are inhibited during Adaptive Tune.