Dwyer DLI - Manual (Page 64)

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Device Menu: Calibration
Select Calibration from the Device Menu . All data logger devices can be calibrated through the
software. This eliminates the need for opening the device or adjusting potentiometers. Calibration
parameters, as well as the last calibration date, are stored within the device itself in non-volatile
memory. This can be accessed through the software. It also allows the device to maintain calibration
while being used on any computer. Most data loggers can be effectively calibrated using a single
point to correct an offset. In some cases, two points may used to correct for gain and offset errors.
The HTDL-10 uses a single point calibration. The calibration offset is defined as the value the device
reads at zero. Thus, if the HTDL-10 reads 0.5ºC when the correct value is 0ºC, the user would enter
0.5ºC for the calibration offset. The 0.5ºC would then be subtracted from each reading downloaded
from the device, and the data would be correct without any further manipulation. The HTDL-10
Calibration window shown below is displayed when the Calibration command is selected, and a
HTDL-10 is connected to the interface cable. To edit the calibration values, click on the Calibrate
button. The Default button may be used to return all values to their default settings (0.000 for offset
values, and 1.000 for gain values.)
Sample Calibration Screen
For convenience, a Wizard button is available. Select this button to display the Calibration Wizard,
a series of screens with fields can be fill in regarding the behavior of the un-calibrated (all values set
to the default) device. The wizard performs the calculations for the offset and/or gain values and puts
them into the correct fields in the calibration window. To commit to any changes, select Save to store
the calibration information in the device. The calibration is then saved, and the new calibration
values are displayed on the screen.
The Calibration Wizard
The Calibration Wizard displays information which correlates to the type of device attached. The
following screen is an example of a Temperature Gain/Offset calibration on the Temperature channel
of a HTDL-10 device. To calibrate the device select the Next button, complete the required fields for
each channel of the device, and select the Next button again until the Wizard highlights the finished
button. Select the Finish button and the calculations are made and the correct values are placed into
the Calibration windows. Select Save to save these values into the device.