13
OPERATING INSTRUCTIONS
Control panel
Table 1 shows the basic operation method. Perform key operations in the sequence indicated in the
table. The example in the table is based on the assumption that the temperature is -145
o
C.
Note: The unit is set at the factory that the temperature inside the unit is -150
o
C.
Table 1. Basic operation sequence (Example: Internal temperature –145
o
C)
Description of operation
Key operated
Indication after operation
1
Turn the power switch ON.
----
Setting temperature is displayed and
Third digit will be flashing.
When pressed, the settable digit will
move.
2
Set the desired temperature by
pressing digit and figure shift key.
When pressed, the figure of settable
Digit will increase.
3
Press entry key.
ENT
Setting temperature will be memorized and present
temperature will be displayed.
Note:
Although the value of the internal temperature setting can range from -100
o
C to -159
o
C, the guaranteed
temperature when there is no load is -152
o
C when the ambient temperature is +30
o
C.
When the desired temperature is set, this key should be pressed (SV side). The temperature setting can
be done by section 2 and 3 of Table 1.
Alarm, safety function, and self diagnostic function
This unit has the alarm and safety functions shown in Table 2, and also self diagnostic function.
Table 2 Alarm and safety functions
Kind of alarm at
safety
Situation Indication
Buzzer
Safety
operation
Temperature alarm
If the internal temperature deviates
about 15
o
C higher than the setting
temperature.
ALARM lamp will be flashed.
Intermittent tone (about
15 minutes later)
Remote alarm will
be active.
(about 15 minutes
later)
Power failure alarm
When the power fails.
ALARM lamp will be flashed.
Intermittent tone
Remote alarm will
be active.
Filter check
When the condenser filter is
clogged.
Filter check lamp will be
flashed.
Intermittent tone
Automatic back-up
[MDF-1155ATN]
If the internal temperature deviates
from the alarm temperature or more.
-----
-----
Liquid N
2
back-up
If the temperature sensor goes open
circuit.
E1 will be displayed.
-----
Thermal sensor
abnormality
If the temperature sensor goes short
circuit.
E2 will be displayed.
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