Specifications

8
Additional Functions Section 1-5
1.5 Additional Functions
In addition to the random read and write access to PLC variables, a 11-byte memo-
ry area is specified in the application description as a poll area. The location of this
memory area can also be specified in the application description.
The only marginal conditions regarding this memory area is that the PLC must be
able to access in bit-mode and the terminal in byte-mode and the memory area
must be contiguous.
Access modes of the PLC to the poll area are:
Byte-structured Memory Mapping
The maximum size for the data area is 11 bytes.
Example:
The cyclic poll area is set to flag byte (MB) 12 in the programming system.
Access to the PLC occurs via:
Byte address MB Description
Byte address +0 MB12 Write coordination byte
Byte address +1 MB13 Message channel low-byte
Byte address +2 MB14 Message channel high-byte
Byte address +3 MB15 Function key LED 1 to 4
Byte address +4 MB16 Function key LED 5 to 8
Byte address +5 MB17 Function key LED 9 to 12
Byte address +6 MB18 Function key LED 13 to 16
Byte address +7 MB19 Function key LED 17 to 20
Byte address +8 MB20 Function key LED 21 to 24
Byte address +9 MB21 Function key LED 25 to 28
Byte address +10 MB22 Function key LED 29 to 32
Word-structured Memory Mapping
The maximum size for the data area is 6 words or 12 bytes.
Example:
The cyclic data area is set to DW21 in the programming system.
Word address DW High-byte Low-byte
Word address +0 DW21 Write coordination byte Reserved
Word address +1 DW22 Message channel high-byte Message channel
low-byte
Word address +2 DW23 Function key LED 1 to 4 LED 5 to 8
Word address +3 DW24 Function key LED 9 to 12 LED 13 to 16
Word address +4 DW25 Function key LED 17 to 20 LED 21 to 24
Word address +5 DW26 Function key LED 25 to 28 LED 29 to 32