EXFO IQS-1500 Power Meters for IQS-500/600 - Manual (Page 55)

Performing Acquisitions
Power Meters 47
Starting the Acquisition
You can also start the acquisition in the Graph tab by clicking the Start
button the same way you would in the Control tab.
To enter a name for your acquisition, type it in the File box of Data
Acquisition File. The default extension is .tra.
I
MPORTANT
If you change units on the channel using Relative or Absolute mode
and that you had enabled Graph mode, the Graph and Start
buttons might automatically disable themselves if the resulting
changes are not compatible with the base unit used in the graph.