Omron CVM1D Operation Manual page 351

Special Instructions
Control Data
Diagnostics Output
1, 2, 3...
346
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.
When IR 00000 to IR 00003 are ON in the following example, the normally
closed condition IR 00002 would be found as the cause of the diagnostic output
not turning ON.
00000
00001
The logic diagnosis operation runs independently from the time monitoring op-
eration. The bit address information bit (bit 15 of D) can be examined to see if
information has been output for logic diagnosis.
The function of the control data bits in C are shown in the following diagram.
C: 15 14
Not used. Set to zero.
Diagnostics output
0 (OFF): Bit address output (binary)
1 (ON):
There are two ways to output the bit address of the OFF condition detected in the
logic diagnosis operation.
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.
D: 15 14 13
D+1 contains the memory address of the operand of the input condition. The
absolute memory address is given in the same form used for indirect ad-
dressing. Refer to Section 3 Memory Areas and to the discussion of indirect
addressing on page 62 for details on absolute memory addresses.
2. Bit address and message output (used when bit 15 of C is ON).
Bit 15 of D indicates whether or not there is bit address information stored in
D+1 to D+3. If there is, bit 14 of D indicates whether the input condition is
normally open or closed. Refer to the following table.
00002
00003
08 07
Bit address and message output (ASCII)
Input condition
0 (OFF): Normally open
1 (ON): Normally closed
Bit address information bit
0 (OFF): Not recorded in D+1.
1 (ON): Recorded in D+1.
Section 5-27
Diagnostic
output
00
FAL number
(2-digit BCD, 00 to 99)
00
Not used.