B Error And Arithmetic Flag Operation - Omron CPM1 - PROGRAMING MANUAL 02-2001 Programming Manual

The following table shows the instructions that affect the ER, CY, GT, LT and EQ flags. In general, ER indicates that
operand data is not within requirements. CY indicates arithmetic or data shift results. GT indicates that a compared
value is larger than some standard, LT that it is smaller, and EQ, that it is the same. EQ also indicates a result of
zero for arithmetic operations. Refer to Section 7 Instruction Set for details.
Vertical arrows in the table indicate the flags that are turned ON and OFF according to the result of the instruction.
Although ladder diagram instructions,TIM, and CNT are executed when ER is ON, other instructions with a vertical
arrow under the ER column are not executed if ER is ON. All of the other flags in the following table will also not
operate when ER is ON.
Instructions not shown do not affect any of the flags in the table. Although only the non-differentiated form of each
instruction is shown, differentiated instructions affect flags in exactly the same way.
The ER, CY, GT, LT and EQ Flags are turned OFF when END(01) is executed, so their status cannot be monitored
with a Programming Device.
The status of the ER, CY, GT, LT and EQ Flags is affected by instruction execution and will change each time an
instruction that affects them is executed. Differentiated instructions are executed only once when their execution
condition changes (ON to OFF or OFF to ON) and are not executed again until the next specified change in their
execution condition. The status of the ER, CY, GT, LT and EQ Flags is thus affected by a differentiated instruction
only when the execution condition changes and is not affected during scans when the instruction is not executed,
i.e., when the specified change does not occur in the execution condition. When a differentiated instruction is not
executed, the status of the ER, CY, GT, LT and EQ Flags will not change and will maintain the status produced by
the last instruction that was executed.
Instructions 25503 (ER)
TIM
CNT
END(01) OFF
STEP(08) Unaffected
SNXT(09)
CNTR(12)
TIMH(15)
WSFT(16)
CMP(20)
MOV(21)
MVN(22)
BIN(23)
BCD(24)
ASL(25)
ASR(26)
ROL(27)
ROR(28)
COM(29)
ADD(30)
SUB(31)
Appendix B
Error and Arithmetic Flag Operation
25504 (CY) 25505 (GR)
Unaffected Unaffected
OFF OFF
Unaffected Unaffected
Unaffected
Unaffected Unaffected
Unaffected
Unaffected
Unaffected
25506 (EQ) 25507 (LE)
Unaffected Unaffected
OFF OFF
Unaffected Unaffected
Unaffected
Unaffected
Unaffected
25402 (N) Page
Unaffected 389
394
OFF 381
Unaffected
385
385
395
390
405
Unaffected 432
411
412
OFF 439
Unaffected 440
405
OFF 406
406
407
479
Unaffected 457
458
565