non-recognition of the size of the sampling vial IN HEAD SPACE 7697A

What size vials are you using and what size vials are configured on the 7697A?  It sounds like those don't match.  At the front panel of the 7697A, press the [Vial] key and scroll down.  To change the vial size there, you'll need to press [Mode/Type] and select from the list.  The options are 10 mL, 20 mL, and 22 mL.

In Chemstation, it should either be in the instrument parameters on the 7697A tab or the 7697A configuration.  (I don't have Chemstation easily accessible and I don't remember exactly where it is.)

THANK YOU VERY MUCH;

it was useful to me.

but when we launch a sequence it is aborted a few minutes later and the device displays ''needle tray oven error 8''; what to do?

Is that the exact phrasing of the error message?  I can't find any note like that in our documentation.  Please check that the message is correct.  Also look at what is documented in the Event Log and Sequence Log.  Press [Logs] on the front panel of the 7697A, use the arrow keys to select the Event or Sequence Log, and press [Enter].