Cole-Parmer BH-200 Serie Mode D'emploi page 5

temperature as required. If this setting needs
to be repeated regularly it is possible to leave
the control knob in position and use the
switch on the rear of the instrument to turn it
on and off. Note that switching off at the
rear will cause the hot warning light to stop
flashing.
9. After use the instrument should be switched
off at the rear and allowed to cool. It should
then be disconnected from the electricity
supply.
4. Calibration –
Digital models only
These units are calibrated during manufacture
using blocks designed for 16mm tubes. The
different mass of aluminium in blocks designed
for other sizes or types of container can cause
small discrepancies between the displayed
temperature and the actual temperature of the
blocks.
If the block heater is to be used with other blocks
and very accurate temperature setting is required
then the unit should be re-calibrated for the
blocks to be used.
You will need an accurately calibrated
thermometer for this procedure to be
worthwhile. The block heater can only be as
accurate as the thermometer used to
calibrate it.
Follow the procedure outlined below.
1. Begin with items that are cool.
2. The blocks should be pushed firmly to the
right hand side of the recess with no air gap
between blocks. The right hand block will be
used as the calibration block.
3. Switch on the unit and set the temperature
display to 30°C following the procedure
outlined in section 3.1
4. Press all three buttons together and hold for
5 seconds until the amber "heat" light stops
flashing and remains permanently on.
5. Self-calibration will now begin and the unit
will begin to heat.
6. After approximately 30 minutes the unit will
have stabilized at approximately 40°C and the
display will change from showing
temperature to read (EEEE).
7. Accurately measure the block temperature
within the thermometer hole in the right hand
block.
8. Press the set button and release
9. Press and hold the set button and use either
the up or down buttons to adjust the display
temperature to equal the actual temperature
measured.
10. Press the up and down buttons together to
confirm the value. The amber "heat" light will
stop flashing and remain permanently on.
11. Self-calibration will now continue and the unit
will ramp up to approximately 5°C below
maximum, i.e. either 125°C or 195°C
depending on model..
12. After approximately 30 minutes the unit will
have stabilized and the display will change
from showing temperature to read (EEEE).
13. Accurately measure the block temperature
within the thermometer hole in the right hand
block.
14. Press the set button and release
15. Press and hold the set button and use either
the up or down buttons to adjust the display
temperature to equal the actual temperature
measured.
16. Press the up and down buttons together to
confirm the value.
17. The unit will now begin to control with the
new calibration parameters.
18. Allow 30 minutes for the temperature to
stabilize.
19. Check that both the display temperature and
the thermometer temperature are now
between 124°C and 126°C or 194°C and
196°C depending on model.
20. Press the set button and release to confirm
the calibration. The set temperature will revert
to 30°C.
21. Reset the set temperature to maximum (130
or 200°C) and allow a few minutes to confirm
that the unit actually achieves that
temperature.
22. Calibration is now complete and the unit may
be used normally.
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