Micromod Micro-DCI: 53SL6000 Single Loop Controller User Manual
Page 108
9.8.1 Executing Easy-Tune
Easy-Tune is executed from the conF-EZ module
parameters. A typical controller display illustrating
Easy-Tune being executed is provided in Figure
9-5. Easy-Tune execution can be aborted at any
time by first pressing either output push button and
then by pressing the mode/select push button. Af-
ter the output push button is pressed, outX appears
in the SP dro and the Easy-Tune LED remains on
but stops blinking.
NOTE 1: For two loop cascade (cASc) control
schemes, the loop to be tuned is selected in
operator mode as the displayed loop before
executing Easy-Tune.
Also, in a cascade control scheme, loop 1
(secondary) is tuned first to the desired response
characteristics. It is then set to automatic with the
remote setpoint enabled before loop 2 (primary) is
selected and tuned.
The general rule for tuning cascade control is that
the secondary loop (loop 1) must be tuned tighter
and faster than the primary loop (loop 2);
otherwise, the setpoint of the secondary, which
comes from the primary, would vary more than the
secondary’s process variable, resulting in poor
control of the primary loop.
The secondary process variable should not
overshoot the input setpoint from the primary by
more than 5 percent.
After the secondary is tuned, ensure the tuned
values conF-cn.1-Pb, conF-cn.1-tr, and
conF-cn.1-td are entered before the primary loop
(conF-cn.2-[Pb, tr, td]) is tuned.
The primary loop is selected in operator mode
before Easy-Tune is executed.
NOTE 2: For two loop high limit/low limit
(h.LiM/L.LiM) control schemes, the loop to be
tuned is selected in operator mode as the
displayed loop before executing Easy-Tune.
To tune loop 1 (primary), of a high/low limit
scheme, loop 2 (limiting) is set so that the output
changes used to tune loop 1 do not cause the
loop 2 limiting controller to modify the output
value, as this will give erroneous results. When
tuning loop 1 (primary) the hard manual limit
parameter conF-cn.1-hML is set to off.
To tune loop 2 (limiting) of a high/low limiting
scheme, the loop 2 (limiting) output is manually
adjusted to the desired process limiting value and
the loop 1 (primary) display is then selected in
operator mode and set to automatic. The
controller is placed in local and the setpoint push
buttons are used to move the loop 1 (primary)
setpoint to the extreme end of the instrument
range, either to the high end for high limiter or the
low end for low limiter. This setpoint value
ensures the loop 2 (limiting) output value plus the
DOUT +/- output step change value induced by
Easy-Tune do not interact with the setpoint. In
effect loop 1 (primary) is decoupled.
The steps to execute Easy-Tune are as follows:
1.
Press and hold the mode/select pb to enter
engineering mode.
2.
Press the scroll forward pb until the conF
prompt appears in the green dro.
3.
Press the select pb.
4.
Press the scroll forward pb until the EZ prompt
appears in the yellow dro.
5.
Press the select pb; the first parameter prompt
(cM) appears in the green dro (it replaces
conF), and its value (P) appears in the red dro.
6.
Press the select pb; the value in the red dro
starts blinking.
7.
Press the scroll forward pb to alter/edit the red
dro value.
8.
Press the select pb to enter the value.
9.
Repeat steps 5 through 8 to alter the remaining
parameters listed in Table 9-2. Selecting YeS
to the run? prompt, which is the last parameter
in Table 9-2, causes Easy-Tune to start exe-
cuting.
Section 9. Commissioning
53SL6000 Instruction Manual
9-5