OS1
US
OS2
T1
T2
T3
T4
Quarter cycle times
Temp
New tuning
values loaded
into memory
Time
Start
AT
Set
Point
75% of
set point
During T1 - 4 the controller
measures heating delays and
rates of heating and cooling
Heat to set point
after entering
new parameters
The autotune sequence.
During autotune the controller heats
to 75% of the set point temperature
where it oscillates for several cycles
before loading the new tuning
parameters. After the tuning
parameters are loaded it heats to the
set point temperature. Tuning below
the set point prevents any damage
that might occur from overheating.
Autotuning the Controller for Very Fine Control.
This procedure is not recommended for heating mantles (see Section 2.3) and has not effect on the
cooling outlet.
In the majority of cases, the procedure above results in stable temperature control with any heater. A
second version of the autotune routine is available and can be used when the heater is already at or
close to the set point, is being tuned at a temperature close to room temperature, or for very fine
control in demanding situations. If stable temperature control doesn’t result after performing the first
autotune routine, the procedure below should be performed. Before performing the ‘fine tune’
autotune procedure, the ‘regular’ autotune procedure that precedes this should normally be performed.
1.
Set the equipment up in the exact configuration it will be used. If the heater has its own
thermostat or power controls, turn both as high as they’ll go. With this procedure it’s not
necessary for the equipment to start at room temperature. This procedure can be performed at
any time and any temperature.
2.
Set the controller to the appropriate power level (see Section 3.6). Turn the controller and
heater on, then enter the desired set point temperature.
3.
Press and hold in both the
and
buttons (for 3 seconds) on the front of the temperature
▲
▼
meter until the word “
tunE
” appears in the display then release both buttons.
4.
Press the
button (5 times) until “
▲
CyC.t
” appears in the display (if you go past this setting,
press the
button until you get back to it).
▼
5.
First hold in the ‘*’ button, while holding in the ‘*’ button press the
button. Continue to
▼
hold both buttons in until the display reads “
A --
”, or “
A ##
” where “
##
” is some number.
6.
Release the ‘*’ button and press the
button until “
▼
tunE
” once again appears in the display.
7.
Press and hold the ‘*’ button and “
tunE
” will change to “
off
” to indicate that autotune is
currently off.
8.
While holding in the ‘*’ button, press the
button to change the display to “
▲
At.SP
”, then
release both buttons.
9.
Press and hold both the
and
buttons ( 3 seconds) until the temperature appears in the
≈
▲
▼
display. The controller is now in its autotune mode. While in autotune the display alternates
between “
tunE
” (for autotune) and the process temperature. When the autotune sequence is
done (this may take in excess of an hour) the controller stops displaying “
tunE
” and only
displays the process temperature. [To abort autotune manually, repeat steps 3, 8 and 9 except in
step 8 press the
button until “
▼
off
” is displayed].
9
