How can I check freehand messages (signatures) with SMARTDAC+ GX/GP series?

If you load a data file that includes a freehand signature in the Universal viewer, you can view the freehand signature in the Image Mark dialog box. Also, an "Image bar" and "Image button" are displayed above the waveform display. The image button indicates the image mark display condition. You can use it to change the display.
For details, see section 3.1, "Displaying Waveforms" in the user's manual.
User's Manual (IM 04L51B01-01EN)