Calibrating the T1 Baseline (T1 Heat Flow)Calibrating the T1 Baseline (T1 Heat Flow)
The baseline slope and offset calibration involves heating an empty cell through the entire temperature range expected in subsequent experiments. The calibration program is used to calculate the slope and offset values needed to flatten the baseline and zero the heat flow signal. This calibration is used in the DSC Q20 and Q10, and when the selected heat flow is T1 for the DSC Q2000, Q1000, Q200, or Q100.
Baseline Slope is a calibration constant that accounts for the baseline slope of an empty cell. The baseline slope is calculated from data gathered as an empty cell is heated through the temperature range expected in subsequent experiments. Default is 0.00.
Baseline Offset is a calibration factor that shifts the curve up or down along the Y-axis to balance the heat flow at the sample and reference thermocouple positions. The baseline offset is calculated from data gathered as an empty cell is heated through the temperature range expected in subsequent experiments.
Follow these basic instructions for baseline slope and offset calibration. Click the links to jump to the specific instructions for that item.
Gather baseline calibration data, which involves heating an empty cell through the entire temperature range expected in subsequent experiments. You can do this one of two ways:
Automatically using the Platinum™ functions. (This function is available for Q2000, Q200, and Q20 instruments only and is recommended for first time calibration.)
Manually using the templates, or custom methods.
Step-by-step using the Calibration Wizard.
Analyze the data. You can do this one of several ways:
Automatically as part of the Platinum functions. (This function is available for Q2000, Q200, and Q20 instruments only and is recommended for first time calibration.)
Automatically by defining Post Test Actions (can be applied to templates). (This function is available for Q2000, Q200, and Q20 instruments only and is recommended for first time calibration.)
Manually by specifying the appropriate file then analyzing the data using Calibrate/Analysis (where you specify the desired analysis limits).
Step-by-step using the Calibration Wizard.
Choose from optional Platinum functions:
Scheduling the calibration sequence (either created through Platinum or your own custom method).
Enabling run and sequence messaging.
Print out the .emf calibration file for your records. This file is created after automatic calibration and placed in the same folder used for your data files. It will be named for the sample name entered: e.g., samplename.emf.
Baseline calibration involves heating an empty cell through the entire temperature range expected in subsequent experiments. The calibration program is used to calculate the slope and offset values needed to flatten the baseline and zero the heat flow signal.
You can gather data one of two ways:
Automatically using the Platinum functions. (This function is available for Q2000, Q200, and Q20 instruments only and is recommended for first time calibration.)
Manually using the templates, or custom methods.
Step-by-step using the Calibration Wizard.
A general procedure for baseline calibration is given below:
Remove any pans from the cell and cover the cell.
Check that your purge gas is connected and set to the desired flow rate. If you are using an RCS or LNCS, be sure a Base purge gas is also used.
Select Experiment View and access the Summary Page, then set the instrument to "Calibration mode" using the Mode drop-down list.
Select the "Baseline" test from the Test list.
Select "Baseline" from the Sample Name list.
Enter the requested sample information, including the exact Sample Size (zero) and Pan Type (none).
Click on the Procedure tab. Enter the requested test parameters that will heat the DSC cell over the same temperature range, at the same heating rate that will be used for subsequent experiments.
Click on the Notes tab. Enter/verify the requested information. If an MFC is installed, set the desired flow rate.
Click on the Apply button to save the experimental and sample parameters entered for this run.
If more than one run is in the sequence list, schedule this run. (An arrow will appear next to the run number in the Sequence Pane for the scheduled run.)
Select Start to begin the calibration run.
Wait until the run is complete, then access the calibration program using Calibrate/Analysis on the DSC menu.
Analyze the data. See Analyzing DSC Calibration Data.
Save the calibration results by clicking the Accept button (or by selecting Analyze/Accept results from the Calibration menu). This will update the current temperature parameters with this calibration data.
You can verify this result by viewing the Cell Calibration Table (selected from the Calibrate menu).
For basic calibration information see: Calibrating the DSC.
Once the calibration run is complete, you can analyze the data using one of the following techniques:
Automatically as part of the Platinum functions. (This function is available for Q2000, Q200, and Q20 instruments only and is recommended for first time calibration.)
Automatically by defining Post Test Actions (can be applied to templates). (This function is available for Q2000, Q200, and Q20 instruments only and is recommended for first time calibration.)
Manually by specifying the appropriate file then analyzing the data using Calibrate/Analysis (where you specify the desired analysis limits).
Step-by-step using the Calibration Wizard.
Select Calibrate/Analysis from the main menu. (See Analyzing DSC Calibration Data for more detailed information.)
Select "Baseline Calibration."
Select the calibration file obtained above.
Once the plot is displayed, click on the Analyze button (or choose Analyze from the pop-up menu).
Position the cursors as desired.
Save the analysis. Right click on the curve and select the Accept Results function. The values will be automatically entered in the Calibration table when the analysis has been saved. To view the calibration results, see the Calibration report.
NOTE: These functions are available for Q2000/Q200/Q20 instruments only.
This method utilizes Post Run Actions to automatically analyze and send the results to the instrument. These are defined while setting up the run sequence and executed at the end of each test.
Set up the calibration run sequence manually as described above.
Right click on the second Tzero calibration run number on the Sequence Pane to display the pop-up menu. Select Post Run Action.
Select one of the following:
IF NOT -- Successful T1 Baseline Calibration -- STOP. (This will stop the sequence if the baseline calibration fails.)
DO -- T1 Baseline Calibration. (This will begin the next run after performing baseline calibration, with no dependency on the outcome of the verification criteria result.)
IF -- Successful T1 Baseline Calibration -- GO next sequence. (This will start the standard run sequence after successful completion of baseline calibration.)
Select OK when finished.
Select Start to begin the calibration run. To view or print the baseline calibration results, see the Calibration report.
