Computer Hardware User Manual

311
When the execution condition is OFF, FPD(––) is not executed. When the
execution condition is ON, FPD(––) monitors the time until the logic diagnostics
condition goes ON, turning ON the diagnostic output. If this time exceeds T, the
following will occur:
1, 2, 3... 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 logic diagnostic instructions are searched for the first OFF input condi-
tion and this condition’s bit address is output to the destination words begin-
ning at D.
3. The CY Flag (SR 25504) is turned ON. An error processing program section
can be executed using the CY Flag if desired.
4. 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.
Control Data The function of the control data bits in C are shown in the following diagram.
15 14 08 07 00
FAL number
(2-digit BCD, 00 to 99)
C:
Not used. Set to zero.
Diagnostics output
0 (OFF): Bit address output (binary)
1 (ON): Bit address and message output (ASCII)
Logic Diagnostic Instructions If the time until the logic diagnostics condition goes ON exceeds T, the logic diag-
nostic instructions are searched for the OFF input condition. If more than one
input condition is OFF, the input condition on the highest instruction line and
nearest the left bus bar is selected.
00000 00002
00001 00003
Diagnostic
output
When IR 00000 to IR 00003 are ON, the normally closed condition IR 00002
would be found as the cause of the diagnostic output not turning ON.
Diagnostics Output There are two ways to output the bit address of the OFF condition detected in the
logic diagnostics condition.
1, 2, 3... 1. Bit address output (used when bit 15 of C is OFF).
Bit 15 of D indicates whether or not bit address information is stored in D+1.
If there is, bit 14 of D indicates whether the input condition is normally open
or closed.
15 14 13 00D:
Not used.
Input condition
0 (OFF): Normally open
1 (ON): Normally closed
Bit address information
0 (OFF): Not recorded in D+1.
1 (ON): Recorded in D+1.
Special Instructions Section 5-25