Manual
Chapter 8
838
Planning Data Blocks for PLC3
With a PLC-3 processor, the most straightforward way to arrange the data
blocks is to put them all in the same file and use the address pointers to
specify word offsets within the file as follows:
Block Word
Status 1
10
Parameter
101 144
Moveset 1 for axis 1
201 224
Moveset 2 for axis 1
301 315
Moveset 3 for axis 1
401 435
Moveset 1 for axis 2
501 51
1
Command
601 608
Remember that the 1771-M3 controller will not accept an address pointer
of 000. Therefore, never start a block at word 0.
In this example, we started the blocks at words 1, 101, 201, 301, 401, 501
and 601 so that the numbers of their words would correspond to their
descriptions in chapter 7.
In this example, we used a file in the decimal (BCD) section of the data
table to keep the ladder-diagram program simple. Remember that the
1771-M3 controller will only accept BCD values for address pointers.