No truncate...

backup log PMSdb

to disk='D:\Program Files\Microsoft SQL Server\MSSQL\BACKUP\PMSdb_Log.bak'

with NO_TRUNCATE

Server: Msg 3033, Level 16, State 1, Line 1

BACKUP DATABASE cannot be used on a database opened in emergency mode.

Server: Msg 3013, Level 16, State 1, Line 1

BACKUP LOG is terminating abnormally.

continue after error...

backup log PMSdb

to disk='D:\Program Files\Microsoft SQL Server\MSSQL\BACKUP\PMSdb_Log.bak'

with CONTINUE_AFTER_ERROR

Server: Msg 155, Level 15, State 1, Line 3

'CONTINUE_AFTER_ERROR' is not a recognized BACKUP option.