Temperature monitoring in T-App is done by sending a command such as [F1 CT +3] or [F1 CT ?] to the temperature controller; the controller then sends replies in the form [F1 CT 31.27] at 3 seconds intervals for the first command (specified by the +3). CT is an abbreviation for Cell holder Temperature. The temperatures and corresponding times are stored in computer memory and plotted (as black lines) in the application window.
The Heat exchanger Temperature is also collected, command [F1 PT +3] or [F1 PT ?], reply example [F1 HT 24.53] ). The time / HT data are not shown immediately after the program starts running, but it is being collected. The user can include the time/HT data in the plot by selecting a menu command, Plot>(Data Shown)>(Sample Heat Exchanger); the same menu command can be used to remove the data from the plot.
If a thermistor probe is connected to the external probe socket on the back of the temperature controller, the Probe Temperatures are also collected, command [F1 PT +3] or [F1 PT ?] and reply example [F1 PT 31.02] (at 3 second intervals for the first command). The thermistor probe is typically used to monitor the temperature of the sample in the cuvette. The first thermistor probes from QNW, the Probe/QNW1 and Probe/QNW2, have been discontinued in favor of the new Probe/10K designed for use with the TC 1 temperature controller which is the controller provided with the majority of our cuvette holders, and with the qpod 3 integrated controller/cuvette holder designed for fiber spectroscopy applications.
Example of a time/temperature plot
If the sample holder is a dual, with sample and reference cell holders that can be operated linked or independently, the cell holder temperature (command [R1 CT +3), reply [R1 CT 28.32] , plotted on startup) and reference heat exchanger (command [R1 HT +3], reply [R1 HT 26.37] ) are available.
The user has full control of which data appear in the plot and of the range of temperature or time for which the data are shown. The graph can be used to determine when the cell holder temperature or the thermistor probe temperature is stable. It is also useful to monitor during a temperature ramp and to determine when the ramping process is complete.
T-App can copy the graph or the data plotted in the graph to the Windows clipboard to be pasted into compatible program (such as Microsoft Word or Excel).
T-App can save the plotted data (CT, PT or HT) at any time in the form of a simple text file, with each point represented by a line of text consisting of the time and temperature separated by a tab.
The “tab delimited” data files saved from T-App can be opened and loaded by Excel.
The files saved by T-App can be reloaded (and plotted) at a later time. This can be done while connected to a controller, or T-App can be run in an “Offline” mode for this purpose without connecting to a controller.
Actually, T-App can be used to load and plot any data* from text files formatted as (x,y) pairs separated by a tab. The user is permitted to change the axis labels as needed.
*If the values are very small or very large, the graph tick labels will not display correctly.