Rockwell Automation 1772-L8_LW_LWP_LX_LXP,D17726.5.8 User Manual - Manual (Page 202)

EAF Logarithmic, Trigonometric
and FIFO Instructions
Chapter 15
15-9
Figure 15.8
FIFO Load and FIFO Unload Ladder Diagram
130
EXECUTE AUX
FUNCTION
FUNCTION NUMBER:
DATA ADDR:
RESULT ADDR:
28
030
050
050 060
000
G
040
000
G
041
000
G
042
000
G
043
000
G
00 15
FIFO Load
Conditioning Bit
Current Data
Being Loaded
File Full Bit
030
G
031 032
060
G
040 005
File Address
Result Word Address (Number of Words Currently in File)
Input Word Address
File Length
G ( )
070
00
050
000
G ( )
070
00
044
000
G ( )
070
00
The File
130
EXECUTE AUX
FUNCTION
FUNCTION NUMBER:
DATA ADDR:
RESULT ADDR:
29
033
050
050 061
000
G
01 14
FIFO Unload
Conditioning Bit
Current Data
Being Unloaded
Output Word Address
FIle Enpty Bit
033
G
034 035
061
G
040 005
G
File Length
( )
070
00 Output Word Address File Address
Input Word Address
Important: Read chapter 19 and become familiar with the concepts
introduced in this chapter before attempting FIFO instructions.
Figure 15.9 shows data (111) in the Input Word 060 ready to be loaded into
the File. Toggle the precondition bit 13000 from false to true (0 to 1).
Each time data is entered into the file, it is placed in the highest available
address in the file. Observe that transferring data from the Input Word to
the File does not destroy the data in the Input Word. Also, the Result Word
(050) increments by 1 each time a transfer is performed. The Result Word
indicates the number of words in your file at any given time. You can
monitor the Result Word for this information.