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AUTO / MANUAL OPERATION
The AUTO / MANUAL function allows you to manually adjust the output of the control. This is normal-
ly used during process setup or start up. It can also be used for troubleshooting. To switch from AUTO
to MANUAL press INDEX to
Auto
. Press the UP ARROW to select
OFF
and press ENTER.The
MANual indicator will light and the lower display will change from normal to showing the actual output
in percent. The value will be the actual percentage of output that was active when the key was
pressed. This is usually known as "bumpless transfer".
If you wish to change the output while in manual, press the UP ARROW or DOWN ARROW keys to
change the value, and press ENTER to retain it. It is important to remember that the value of the dis-
play can be read as 0 to100% of the full control output, or 0 to 100% of the range between S1OL and
S1OH or S2OL and S2OH. If
APct
is set for
rEAL
, a reading of 50% in MANUAL represents 10 mA.
If
APCt
is set for
AdJ
, then 50% in MANUAL will represent the mid point in output between
S1OL
and
S1OH
. (Assuming
S1OL
is
20
and
S1OH
is
100
[4 to 20 mA], 50% will represent 12 mA.)
To return to AUTOmatic control, press the ENTER until
Auto
is displayed. Press the DOWN ARROW
key to
On
, and press ENTER. The MANual indicator will go out, and the set point will take over. If you
want bumpless transfer back to AUTO, while in manual, slowly change the percentage of output until
the process variable matches (or at least is close) to the set point.The further away the PV is from the
set point, the greater the "bump" or upset there will be in the output.
OPERATION OF SELF TUNE® FUNCTION
Self Tune
®
allows automatic selection of the necessary parameters to achieve best control operation
from your 32A Series control. If you are using the control output as a simple on-off function (
Out1
set
for
OnOF
), none of the following will apply.
Theory of Operation
The Self Tune function calculates the
Pb1, rES,
and
rtE
parameters under the
PID tunE
selection, and
the
Fbnd
and
FrtE
parameters, as shown in the Secondary Menu. These values are determined by
measuring the response of the process connected to the control. When Self Tune is started, the con-
trol temporarily acts as an on-off control. While in this mode the control measures the overshoot and
undershoot of the process, and the period of the process (the time from peak value to the next peak
value). These measurements are collected over a period that lasts three periods of overshoot and
undershoot.The data collected over this time is then compared and calculated into final PID and Fuzzy
Logic values. The effect of Fuzzy Logic on the process is still controlled by the
Fint
(fuzzy intensity)
setting. If
Fint
is
0
, the
Fbnd
and
FrtE
will be calculated, but will have no effect. The calculations for
the PID values are the same as used in the standard Ziegler - Nichols equations that have been rec-
ognized as standard for decades.
The only modification to the application of the Ziegler - Nichols equations is controlled by the
dFAC
menu item. This menu item controls the amount of rate (derivative) that is applied. A
dFAC
setting of
3
(factory default) or less allows for less damping. A
dFAC
setting of
4
allows for critical damping as
set forth in Ziegler - Nichols. A
dFAC
setting of
5
or more allows over damping of the process.
Program Setup and Operation
In the secondary menu set
tunE
to
SELF
. Skip
LErn
and check to make sure that
dFAC
is set to the
desired value. Back up to
LErn
and set to
YES
. The control will begin the Self Tune function. While the
Self Tune function is active, the right hand decimal point on the lower display will blink. When Self Tune
is complete, the blinking will stop.
After Self Tune is complete, the
tunE
setting automatically switches to
PID
. This allows examination
and / or modification of the values calculated. We recommend that you do not change the calculated
values unless you have a firm understanding of the parameters involved and their function. For more
information on PID tuning, please contact your supplier.
Summary of Contents for LOVE CONTROLS 32A Series
Page 45: ...Page 9 Timer Functions ...
