PerkinElmer LS 55, User Manual

Page: 126 / 202

126 . LS 55 User’s Guide
Special characters are as follows:
• BS or % characters may be used to delete the previous character in a
command string.
• NULL and DEL are ignored.
• DC1 prompts output when in prompted mode or causes return to free-running
mode in the case that prompted mode was entered by receipt of DC3. Up to
32767 prompts may be accumulated. DC1 is ignored in free running mode.
• DC3 causes entry to prompted mode if in free-running mode, otherwise it is
ignored.
Data is output in the form of records of up to 126 ASCII characters terminated with
c/r and l/f or as a fixed length record of 40 bytes in the case of binary data
transmission. The first response to any command is an output record consisting of a
4 digit error code. On some commands other output records may follow. The last
transmission in response to a command is an error code output record. Any output
records that do not contain only an error code have a DEL character in the first
position.
In some cases the user may start an operation which requires some interaction with
the user (for example, calibration procedures). In such cases unique error codes
may be returned indicating to the user that either text or spectral data records are
to follow. Another unique code indicates that no more data will be sent in response
to this command but that the operation started is still active and is awaiting
instruction in the form of one of the dialogue commands (for example, Continue).
Only when the operation has finished will one of the normal error codes be sent
indicating success or failure of the whole operation.