Tb - Table Function; Writing To A Table; Reading From The Table - Eaton easyE4 series Manual

6. Function blocks
6.1 Manufacturer function blocks

6.1.5.6 TB - Table function

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General
easyE4 base devices provide 32 table function function blocks,
TB01 through TB32.
The table function block allows you to easily create and read
table entries in the form of double words (32 bit).
You can select a LIFO or FIFO function for read operations.
A table can contain up to 16 double words.
Operating principle

Writing to a table

The function block is enabled when EN=1. When the function block is enabled and there
is a rising edge at the function block input, the current value at function block input I1
will be added to the table. Every time there is an edge, a double word (32 bits) will be
assigned a value.
It is permissible to simultaneously activate the EN coil and the WP coil with a rising
edge.
Every new table entry will be appended after the last entry until the sixteenth entry is
reached. At the same time, function block output QN will be incremented by 1. QN indic-
ates the current number of entries. If I1 is added successfully, the input value that was
just entered will be output at function block output QV.
Once the maximum number of 16 table entries is reached, no more data will be added to
the table. If you want to keep making table entries in this scenario, you will first need to
clear the entire table with a rising edge at function block input RE. Function block output
QN will be set to 0 in this case.

Reading from the table

A table can be read from the table's beginning or end.
When there is a rising edge at the RF coil, the oldest value in the table will be read and
output at output QV (FIFO function).
The read operation deletes this value from the table and the actual number of entries is
decremented by 1 at the QN output.
A rising edge at the RL coil causes the most recent value entered in the table to be out-
put at QV (LIFO function).
The read operation deletes this value from the table and the actual number of entries is
decremented by 1 at the QN output.
easyE4 11/18 MN050009 EN www.eaton.com