14
4.3
Default Conditions on Start-up
There are two choices of start-up conditions, referred to as “Auto-Start” and “Non-Auto
Start” as follows.
Non-Auto Start
•
Gas flows equal zero;
Heat exchanger is Off
To set these start-up conditions:
Set the heat exchanger off by pressing the OFF button on the left-hand side of the front
panel.
Use the STORE function: press and hold the recessed button CAL/STORE using a pointed
object and press the SET button in the left-hand group of buttons. The letters “Stor” will
appear on the display. (NB This will interrupt the flow momentarily.)
Auto-Start
•
Gas flows non-zero - can be configured to any desired value.
Heat exchanger in Automatic mode
Auto-Start is useful if there is a possibility of brief power failures when the Cryojet is
running unattended.
Do not select Auto-Start unless you are sure that there
will be liquid nitrogen in the dewar when the controller is switched on.
To set these start-up conditions use this procedure, illustrated in Figure 2:
1.
Set the desired SET temperature.
2.
Set the desired start-up gas flows.
3.
Set Automatic mode by pressing the ON button on the left-hand side of the display.
4.
Use the STORE function: press and hold the recessed button CAL/STORE using a
pointed object and press the SET button in the left-hand group of buttons. The letters
“Stor” will appear on the display. (This will interrupt the flow momentarily).
When the controller is switched on it will display the message “Auto” for a second or two
if it is in Auto-Start mode.
4.4
Low Nitrogen Level Cut-out
A sensor attached to the sample flow unit dewar leg detects the presence or absence of
liquid nitrogen. If the liquid level is below about 6 cm from the bottom of the dewar, all
the heaters in the system will switch off automatically and the message “Lo N” will be
displayed. To restore normal operation after you have refilled the dewar, you must switch
the controller off and on again.
