Writing CreateDate tag from file name

[Snail]

Hi All,
I'm new to ExifTool and this forum,so I apologize for the silly question.
I have a set of about 600 tiff images that do not have the CreateDate EXIF field filled out and am not able to edit it in any ways (I tried with several tool including Exiftool and Windows to no avail.
I also tried using the following Perl script (found on another forum), but no luck either:

exiftool '-CreateDate<${FileName;use Date::Manip;
                      Date_Init("DateFormat=non-US");
                      /on (.*?_.*?[AP]M)/;$_=$1;
                      y/./:/;$_=UnixDate($_,"%Y-%m-%d %T")
                      }' ./*on\ *_*[PA]M*.tiff

What I need: batch fill in the CreateDate Exif tag from the file name date and time (as per the attached samples) for the 600 photos.

Do you have any tips or suggestions?

Thanks in avance for any feedback you may provide.

Best Regards

Snail

[Snail]

Hi, sorry
I'm attaching two missing images.

Snail

[StarGeek]

In the image I checked, the problem seems to be that the Makernotes are unrecognized and/or corrupt.  I'd wait until someone else takes a look at the files but if you don't need the Makernotes, they can be removed with
Exiftool -Makernotes=

Then, you can just use
Exiftool "-createdate<filename"

[Phil Harvey]

The minor error is because the maker notes are unrecognized, so you must add -m to the command to ignore this if you want to write to the file:

exiftool "-createdate<filename" -m FILE

- Phil

[Snail]

Hey Guys, you're really awesome!!!

I just processed the 600 some images and it just went great.

I really appreciate your support.

Snail