Specifications

CP143 H1 / TCP/IP manual The CP143 H1 / TCP/IP network board
Rev. 00/07 4-21
4.3.5.2 SEND / RECEIVE with TRADA (Transparent data exchange)
TRADA stands for transparent data exchange. Transparent data exchange allows to transmit data of
varied length. A 16-byte header which indicates the length is preceding the user data which have to
be transmitted.
For the use of TRADA it is permitted to give in the PLC user program a joker length within the
length instruction.
Through the input of 1 as a lengths instruction into the RECEIVE-FB (parameter: ZLAE) a
variable user data length (joker length) can be adjusted. For the use of a joker length the respective
data length will be taken on.
The as following described header precedes with TRADA functionality a SEND command and is
evaluated from the RECEIVE command.
length instruction of used data
length instruction
With the length instruction the number of the bytes of a data block is named.
If you synchronise with a block size of 6 (512 Byte), the length instruction results in words
SEND with the type TRADA
OP-code = 07
System identifier ="S"
="5"
Header length =16d
Ident.OP-code =01
OP-code lenght =03
OP-code =07
ORG-block =03
ORG-block length =08
ORG-identifier
DBNR (nicht relevant)
Start- H
adress L
Length H
L
Unused block =FFh
Length unused block =02
Up to 64K data but only for error
No.=0