HP 82479A Owner's Manual page 210

Error Recovery
G.2 CORRUPT SETUP INFORMATION
If an impossible measurement request is sent to the HP 3421A, the RECOVER subprogram will be called.
Since the error relates to instrument configuration, the programs will return to the main menu with the
EF: prefix, or in the case of LIIi5, the program will end. A corrupt setup may be detected by using the
"et 1f 4 routine prior to running the setup.
G.3 LOOP AND DEVICE ERRORS
If a power fluctuation or device failure causes the loop to break or an invalid message to return to the
HP-71, the RECOVER subprogram is called in an attempt to handle the error. In many cases this will be
sufficient to keep the system running. If the loop cannot be restored by the FEE IZIIWEF subprogram, the
STEIFF and MOMHI TOR programs will return to the main menu with the EF: prefix. The LOG
program will end with the error message in the display.
If the LIS program ends abnormally and data is being buffered, the file E2LIFFEF may be present in
main memory, containing data that should have been written to the file on the mass storage device. The
program MERISEEILIF (described later in this appendix) may be used to recover the data in the buffer file.
G.4 THE RECOVER SUBPROGRAM
The EECZWEE subprogram in the ITIL ITY file is used to attempt recovery from common interface
problems such as power fluctuations. It may also be used by new programs that use devices on HP-IL.
The call to the EEC ER subprogram is as follows:
CALL REECOVERCEX
The EELCDIWER subprogram in the Data Acquisition Pac takes the following steps:
1) Beeps and displays the error message eg: LIF ERCOEEHM.
2) Returns with E=1 if the error is not HP-IL related.
3) Attempts a RESTORE I, returning with E=8 if successful.
4) Beeps and attempts a RESET HFIL ® EESTOREID ten more times.
5) Returns with the parameter E set to "1" if unsuccessful.
Notice that the recovery subprogram provided works only with the primary interface loop. If more than
one HP-IL interface is in the system, only loop 1 will be restored. A recovery program for more complex
systems should account for the various kinds of errors that can arise on each loop.