GEM80-500 Series Controller
7. Maintenance and Fault Finding
(08/04)
GEM80-500 Technical Manual (T2025En)
Page 7-11
7.9.3
Error Message #105 and I/O Scanning
I/O Scanning
In a similar way to computing the sizes of data tables, so also, a GEM
80-500
Controller computes what I/O ought to be present from the addresses appearing in the
user program. The controller only attempts to read input data from, and send output
data to those I/O devices whose addresses appear in the program. Refer also to the
F-tables, F200 to F329, for further details.
Basic and Verification I/O
Only those Basic and Verification I/O words appearing in the program are included in
the I/O scan. For instance, if the program contains a contact referenced A1.0, the
whole word A1 will be read from the input modules and units. If a module is fitted and
set to an address that is not referred to in the program, this module will not be
scanned; no data will be read from or written to it.
When compilation is attempted the program will not run if any forbidden addresses
have been used in the program, and the programming tool will display a diagnostic
message.
Forbidden addresses are where A-table and B-table addresses have the same number
(e.g. A4 and B4) or where addresses have a number greater than the maximum
imposed by the hardware.
7.9.4
Programming Routine for Correction of Compilation Errors
To correct a program with several errors, the user should use the 'Search' facility to
display and modify the first faulty rung. A recompilation gives information about the
next error. This procedure may be repeated until the program compiles successfully.
Note:
A single error may cause several to be reported, e.g. an incorrect I/O reference.
If the compilation is successful, the following message is displayed on the
programming tool screen for 10/15 seconds, and held on the System Event Log:
'Compiled. Instructions available xxx. Data tables available yyy.'
Each compile error is reported as shown:
'#1xx <compile_error> at rung xxx: yyy, (instruction zzz).'
where xxx is the rung number, yyy is the number of the instruction within the rung, zzz is
the instruction number within the program.
7.9.5
Compilation Errors and the Controller
Compilation errors cause the controller to continue executing the previous successfully
compiled version of the user program, and give a fault report from the failed
compilation. The System Event Log, available with a suitable GEM80 Programming
Package, can display up to 50 compiler error messages (out of 100 System Event Log
locations).