Rockwell Automation 1761-HHP-B30 MicroLogix 1000 with Hand-Held Programmer (HHP) - Manual (Page 397)

Appendix B
Programming Reference
B–2
Word Function Page
S:23 Reserved B–12
S:24 Index Register B–12
S:25 to S:29 Reserved
B–12
S:30 STI Setpoint B–12
S:31 and S:32 Reserved B–12
Status File Descriptions
The following tables describe the status file functions, beginning at address
S0 and ending at address S32.
Each status bit is classified as one of the following:
•
Status — Use these words, bytes, or bits to monitor controller operation
or controller status information. The information is seldom written to by
the user program or programming device (unless you want to reset or
clear a function such as a monitor bit).
•
Dynamic Configuration — Use these words, bytes, or bits to select
controller options while online with the controller.
•
Static Configuration — Use these words, bytes, or bits to select controller
options prior to saving the user program.
Address Bit Classification Description
S0 Arithmetic and
Scan Status
Flags The arithmetic flags are assessed by the controller following the
execution of certain math and data handling instructions. The
state of these bits remain in effect until certain math or data
handling instructions in the program are executed.
S0/0 Carry Status This bit is set by the controller if a mathematical carry or borrow is
generated. Otherwise the bit remains cleared. This bit is
assessed as if a function of unsigned math. When a STI,
high-speed counter, or Fault Routine interrupts normal execution
of your program, the original value of S:0/0 is restored when
execution resumes.
S0/1 Overflow Status This bit is set by the controller when the result of a mathematical
operation does not fit in its destination. Otherwise the bit remains
cleared. Whenever this bit is set, the overflow trap bit S:5/0 is
also set except for the ENC bit. Refer to S:5/0. When a STI,
high-speed counter, or Fault Routine interrupts normal execution
of your program, the original value of S:0/1 is restored when
execution resumes.
S0/2 Zero Status This bit is set by the controller when the result of certain math or
data handling instructions is zero. Otherwise the bit remains
cleared. When a STI, high-speed counter, or Fault Routine
interrupts normal execution of your program, the original value of
S:0/2 is restored when execution resumes.
S0/3 Sign Status This bit is set by the controller when the result of certain math or
data handling instructions is negative. Otherwise the bit remains
cleared. When a STI, high-speed counter, or Fault Routine
interrupts normal execution of your program, the original value of
S:0/3 is restored when execution resumes.
S0/4 to S0/7 Reserved NA NA