12
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).
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). If tuning Channel 1, make sure
the timer switch is set so that heating is on (see Section 3.5). 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
