User Manual

PLC concepts made easy
4.4 Memory areas, addressing and data types
Easy Book
Manual, 03/2014, A5E02486774-AF
63
Each different memory location has a unique address. Your user program uses these
addresses to access the information in the memory location. The absolute address consists
of the following elements:
● Memory area (such as I, Q, or M)
● Size of the data to be accessed (such as "B" for Byte or "W" for Word)
● Address of the data (such as Byte 3 or Word 3)
When accessing a bit in the address for a Boolean value, you do not enter a mnemonic for
the size. You enter only the memory area, the byte location, and the bit location for the data
(such as I0.0, Q0.1, or M3.4).
Absolute address of a memory area:
A
Memory area identifier
B
Byte address: byte 3
C
Separator ("byte.bit")
D
Bit location of the byte (bit 4 of 8)
E
Bytes of the memory area
F
Bits of the selected byte
In the example, the memory area and byte address (M = bit memory area, and 3 = Byte 3)
are followed by a period (".") to separate the bit address (bit 4).