Installation manual

Publication 1747-RM001G-EN-P - November 2008
B-22 SLC Status File
S:5/0 Dynamic
Config
Overflow Trap Bit
When this bit is set by the processor, it indicates that a
mathematical overflow has occurred in the ladder program.
See S:0/1 for more information.
If this bit is ever set upon execution of the END, TND, or REF
instruction, major error (0020) will be declared. To avoid this
type of major error from occurring, examine the state of this bit
following a math instruction (ADD, SUB, MUL, DIV, DDV, NEG,
SCL, TOD, or FRD), take appropriate action, and then clear bit
S:5/0 using an OTU instruction with S:5/0 or a CLR instruction
with S:5.
•••••
S:5/1 NA Reserved •••••
S:5/2 Dynamic
Config
Control Register Error Bit
The LFU, LFL, FFU, FFL, BSL, BSR, SQO, SQC, and SQL
instructions are capable of generating this error. When bit
S:5/2 is set, it indicates that the error bit of the control
instruction has been set.
If this bit is ever set upon execution of the END, TND, or REF
instruction, major error (0020) will be declared. To avoid this
type of major error from occurring, examine the state of this bit
following a control register instruction, take appropriate
action, and then clear bit S:5/2 using an OTU instruction with
S:5/2 or a CLR instruction with S:5.
•••••
S:5/3 Dynamic
Config
Major Error Detected while Executing User Fault
Routine Bit
When set, the major error code (S:6) represents the major error
that occurred while processing the fault routine due to another
major error.
If this bit is ever set upon execution of the END, TND, or REF
instruction, major error (0020) will be declared. To avoid this
type of major error from occurring, examine the state of this bit
inside your fault routine, take appropriate action, and then
clear bit S:5/3 using an OTU instruction with S:5/3 or a CLR
instruction with S:5.
Application example: Suppose you are executing your fault
routine for fault code 0016H Startup Protection. At rung 3
inside this fault routine, a TON containing a negative preset is
executed. When rung 4 is executed, fault code 0016H is
overwritten to indicate code 0034H, and S:5/3 is set.
If your fault routine did not determine that S:5/3 was set,
major error 0020H would be declared at the end of the first
scan. To avoid this problem, examine S:5/3, followed by S:6,
prior to returning from your fault routine. If S:5/3 is set, take
appropriate action to remedy the fault, then clear S:5/3.
••••
Table B.2 Status File Functions (Continued)
Address Classification Description Fixed
5/01
5/02 5/03 5/04 5/05