Metrohm 832 KF Thermoprep - Manual (Page 20)

4.4 The temperature controller
16
832 KF Thermoprep, Operation
4.4.3 Self-optimization of the control parameters
Self-optimization should only be used when the set temperature cannot
be achieved by the temperature controller or when the actual tempera-
ture varies about the set temperature by more than 2…5 °C (overshoot-
ing).
Preparation
Set the same conditions as would be used in a real determination.
• Set the temperature (T1 or T2) to a value corresponding to a real
determination (e.g. 120 °C).
• Wait until the oven has reached the set temperature.
• Insert a sealed sample vial containing a sample in the oven.
• Lower the work head and completely penetrate the sample vial sep-
tum with the needle.
• Switch on the pump (or open the nitrogen valve) and set the gas
flow to a realistic value which would be used during a proper de-
termination.
Self-optimization
• Start the self-optimization process with EXIT (keep key 37 pressed
down for at least 2s!).
During the self-optimization process "tunE" blinks in the display 31.
When the blinking stops the process is finished. Self-optimization nor-
mally takes 1 to 5 minutes. The duration depends on the selected tem-
perature, i.e. the higher the temperature the shorter it takes.
•
• Save the control parameters which have been determined by press-
ing the EXIT key 37 for 2 seconds.
The self-optimization process can be canceled by pressing the EXIT
key 37 briefly.
4.4.4 Key lock function
The temperature controller settings can be protected against accidental
alteration. On the rear panel of the 832 KF Thermoprep the 'Key Lock'
tumbler switch 29 can be switched to 'On'.
If the key lock function is switched on the 'Temperature' tumbler switch
9 can still be used to select the two set temperatures T1 and T2. It is
also possible to switch the pump on and off (key 8).
However, no alteration can be made to the temperature controller 10
with the key lock function switched on.