Techne RS232 User Manual
Page 23
D B - 3 D w i t h R S 2 3 2 O P E R A T O R ’ S M A N U A L
P A G E 21
Over-Temperature Indicator
If the unit should, for any reason, exceed the temperature set for the over-
temperature cutout (see page 17), the over-temperature indicator will light. The
heater will have been switched off and the unit will begin to cool even if the
heater light is on (the light staying on or not depends on which circuit has sensed
an over-temperature).
Setting the Operating Temperature
1. To display the set temperature on the digital display, press and hold the Set
Temperature button.
To adjust the set temperature, press the Set Temperature button and hold it
while pressing the up or down buttons. When the Set Temperature button
is released, the measured temperature is displayed (in degrees Celsius).
2. The heater (and heater indicator) comes on if the set temperature is higher
than the current block temperature.
3. When the measured temperature approaches the set temperature, the heater
indicator will begin to flash. As the measured temperature stabilises the
indicator will stay on for shorter periods.
4. Due to variations in heat losses with different designs of insert block, the
actual temperature may vary. The units are calibrated using model F3506
insert blocks. If you need to control the temperature to a greater accuracy
than the instrument’s set point, place a thermometer in the special hole in one
of the blocks. For greater accuracy still, you can place the thermometer in the
sample liquid in one of the test tubes. In either of these cases, it may be
necessary to readjust the set temperature to achieve the precise temperature
required. Allow the temperature of the unit to stabilise after each adjustment.
5. There will be a time lag between the heater platten and the insert block
achieving the set temperature due to thermal contact between them. This is
particularly true of the DB-3D where the display may reach temperature in
2 or 3 minutes while the insert block may take 12 minutes or more to reach
temperature. Guide times are shown in the Specifications.