Specifications

Additional Functions Section 3-5

3.5 Additional Functions

In addition to the random write and read access to PLC variables, a memory area

comprising 11 or 12 bytes is speciﬁed in the application description as cyclic data

area. The location of this memory area is speciﬁed in the mask deﬁnition and must

be located on a byte boundary.

Only marginal conditions regarding this memory area:

- the PLC must be able to access in bit-mode

- the memory area must be contiguous.

Byte-structured Memory Mapping

The start address must be located on a physical byte boundary.

The following start addresses are possible in accordance with (8 * n) n = 0, 1, 2 : M0,

M8 M16.

Example: Cyclic Data on M0

MSB Description LSB

M7 Write coordination byte M0

M15 Message channel low byte M8

M23 Message channel high byte M16

M31 LED 1 to 4 M24

M39 LED 5 to 8 M32

M47 LED 9 to 12 M40

M55 LED 13 to 16 M48

M63 LED 17 to 20 M56

M71 LED 21 to 24 M64

M79 LED 25 to 28 M72

M87 LED 29 to 32 M80

Word-structured Memory Mapping

Example: Cyclic data on D1

D1 Write coordination byte Reserved

D2 Message channel high-byte message channel low-byte

D3 LED 1 to 4 LED 5 to 8

D4 LED 9 to 12 LED 13 to 16

D5 LED 17 to 20 LED 21 to 24

D6 LED 25 to 28 LED 29 to 32