Chapter 4. Ladder Diagram (LD) Programming
GFK-2950C
February 2018
179
Example for FIFO Read
PRODUCT is a FIFO table with 100 word-sized elements. When the
enabling input PACK_IT is ON, the PRODUCT data item in the table
location pointed to by STK_PTR is copied to the reference location
specified in CART. This table location pointed to would be the
bottom, or oldest data item in the table. The number in STK_PTR is
then decremented. A copy of the oldest data item in the PRODUCT
table is left behind in each table location as the current data is
copied out during successive PACK_IT triggers. Output node EM
passes power when the PTR = 0, firing the coil EMPTY. No further
data from the PRODUCT table can be read without first copying
data in using the FIFO_WRT function.
Summary of Contents for PACSystems RSTi-EP
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