Instruction Set
Diagnostic
3-31
diagnostic instructions continued...
Instruction
Description
Diagnostic Detect
DDT
Status Bits:
EN - Enable
DN - Done Bit
ER - Error Bit
IN - Inhibit Bit
FD - Found Bit
When the input conditions go from false-to-true, the processor compares the number of bits
specified in the Cmp Control Length (20) of the Source file (#I:031) with the bits in the Reference
file (#B3:1). The processor stores the results (mismatched bit numbers) in the Result file
(#N10:0). File R6:0 controls the compare and file R6:1 controls the file that contains the results
(#N10:0). The file containing the results can hold up to 5 (the number specified in the Length
field) mismatches between the compared files. The processor copies the source bits to the
reference file for the next comparison.
The difference between the DDT and FBC instruction is that each time the DDT instruction finds
a mismatch, the processor changes the reference bit to match the source bit. You can use the
DDT instruction to update your reference file to reflect changing machine or process conditions.
Data Transition
DTR
The DTR instruction compares the bits in the Source (I:002) through a Mask (0FFF) with the bits
in the Reference (N63:11). When the masked source is different than the reference, the
instruction is true for only 1 scan. The source bits are written into the reference address for the
next comparison. When the masked source and the reference are the same, the instruction
remains false.
DIAGNOSTIC DETECT
Source
#I:030
Reference
#B3:1
Result
#N10:0
Cmp Control
R6:0
Length
20
Position
0
Result Control
R6:1
Length
5
Position
0
DDT
DATA TRANSITION
Source
I:002
Mask
0FFF
Reference
N63:11
DTR