Omron SYSMAC CV Series Operation Manual page 369

Special Instructions
Time Monitoring
1, 2, 3...
Execution condition
for FPD(177)
Diagnostic output
CY (A50004)
Logic Diagnosis
The following diagram illustrates the type of program section that can be diag-
nosed with FPD(177). The instruction block that is diagnosed by FPD(177)
starts at the fist LD after FPD(177) (excluding LD for TR bits) and ends at the
next output or special (right-hand) instruction (except for OUT for TR bits).
The program sections marked by dashed lines in the following diagram can be
written according to the needs of the particular program application. The proces-
sing programming section triggered by CY is optional and can used any instruc-
tions but LD and LD NOT. The logic diagnostic instructions and execution condi-
tion can consist of any combination of NC or NO conditions desired.
Branch
Execution
condition
(CY Flag)
A500
04
Logic
diagnostic
instructions
When the execution condition is OFF, FPD(177) is not executed. When the exe-
cution condition is ON, FPD(177) monitors the time until the diagnostic output is
executed with an ON execution condition. If this time exceeds T, the following will
occur:
1. An FAL(06) error is generated with the FAL number specified in the first two
digits of C. If 00 is specified, however, an error will not be generated.
2. The CY Flag (A 50004) is turned ON. An error processing program section
can be executed using the CY Flag if desired.
3. If bit 15 of C is ON, a preset message with up to 8 ASCII characters will be
displayed on the Peripheral Device along with the bit address mentioned in
step 2.
The following chart shows the timing that occurs when the execution condition
for FPC(177) turns ON.
Monitoring time
Error detected
FPD(177) also searches for the input condition that is responsible for the diag-
nostic output not turning ON and outputs diagnostic results and, if specified, a
message. The following instructions are examined: LD (excluding LD for TR
bits), LD NOT, AND, AND NOT, OR , and OR NOT. Operands addressed indi-
rectly through index registers, however, are not examined. If more than one in-
put condition is OFF, the input condition on the highest instruction line and near-
est the left bus bar is selected.
(177
FPD C T D
Processing after
error detection.
Diagnostic
output
Monitoring time
Section 5-27
Error not detected because
diagnostic output turned
ON during monitoring time.
357