CPU ADAM 821x
Chapter 4 Deployment of the CPU 821xNET
ADAM 8000 Manual CPU 821x – Rev 1.1
4-33
TRADA stands for
Tra
nsparent
Da
ta exchange. A transparent data
exchange may transfer application data with varying block lengths. A
16Byte header that defines the length of the application data precedes the
application data.
With TRADA you may enter a wildcard length into the PLC application.
If you enter "-1" as length into the RECEIVE-FB (parameter: ZLAE) you are
defining a variable length (wildcard length) for the application data. With
wildcard lengths the actual length of the data is retrieved from the
respective TRADA header.
With the TRADA functionality the following header will precede a SEND job
and it is analyzed by the RECEIVE function.
→
Length of the user data
The length file contains the number of bytes in a data block.
If you are synchronizing with a block size of 6 (512Byte) the length is
entered in words.
SEND / RECEIVE
of the type TRADA
SEND of type TRADA
OP-code = 07
System identifier
="S"
="5"
Header length
=16d
Ident.OP code
=01
OP code length
=03
OP code
=
07
ORG block
=03
ORG block length
=08
ORG identifier
DBNR (
irrelevant
)
Start address
H
L
Length
H
L
Dummy block
=FFh
Dummy block length =02
64K data if error no.=0
Length
