Grant Instruments QBH - Manual (Page 9)

QBD, QBA, QBH, 28089 Ver 12
Operating Manual Page 8
www.grantinstruments.com
EN
Probe Selection
By using the optional external probe, it is possible to control the temperature of a
sample, a dummy sample or the block directly. Ensure the probe is maintained in
contact with either a sample or the block during the course of the experiment. Fail-
ure to maintain this contact could result in the probe monitoring an air temperature
or, another non-specific temperature. This could result in the temperature exceeding
the set point and an error condition occurring (see “Errors” below). Grant has pro-
vided this function to protect accidental operation when the external probe has been
‘selected’ but is not used. When selected the external probe may be calibrated by
the procedure described on page 10.
To select the external probe, complete the following procedure:
1
Press F to enter main menu.
2 Rotate control knob until display shows .
3 Press S to select probe selection.
4 The display will show which probe type is currently selected.  for internal
and  for external.
5 Rotate the control knob until the desired probe is shown.
6 Press S to select the desired probe.
Errors:
1.
The external probe should be plugged in before it is selected. If the
probe is not connected to the unit or disconnected the message  will be
displayed.
2. If a difference of 40°C or more is detected between the internal and
external probe then  will be displayed.
- This condition might occur if the external probe is not in direct contact with a
sample, a dummy sample or the block.
- This error can also occur if the external probe is placed in a cool sample
which is then placed in a pre-warmed block.
To remove an error 3, ensure the external probe is indeed in direct contact
with the chosen target and there is not a difference of more than 40
o C between
the block (measured by the internal probe) and the external probe.
As the sample heats-up, the heater will switch on again as the difference be-
comes less than 40
o C. Therefore the user can wait and err3 will clear.
N.B. Should experimental conditions require a difference of 40 o C or more be-
tween the block and the external probe, please contact Grant to discuss other
options.