Chapter 4 Deployment of the CPU 821xNET
CPU ADAM 821x
4-4
ADAM 8000 Manual CPU 821x – Rev 1.1
H1, which is also referred to as "Industrial Ethernet", is a protocol that is
based upon the Ethernet standard.
H1 information is exchanged between stations by means of H1-frames that
are transferred via transport connections.
A transport connection is a logical link between two access points to the
transport services on different stations. A transport connection is based
upon addressing information that provides an exact description of the path
between the two access points.
The following parameters describe a transport connection individually:
•
MAC address,
also referred to as Ethernet address, gives an unique
definition of the access facility of a station.
•
TSAP
Transport Service Access Points
identify access channels for the
services of the transport protocol.
The CP prepares a data buffer and transfers the data into the data buffer by
means of the background communication function SEND_ALL. Then the
CP creates an H1-frame and transfers this to the partner station as soon as
this has enabled reception. When the partner station has received the H1-
frames, the CP receives an acknowledgment receipt. Next it uses the
background communication function RECEIVE_ALL to transfer the status
of the SEND-job into the respective indicator word.
This ensures error-free communications.
The following illustration shows the principle once again:
Send HTB
Daten
Send_All
Statuswort
Daten
Recv_All
H1-Frame
SEND-Auftrag
Empfangsfreigabe
H1-Frame
CPU
CP
Empfangsquittung
jedes Frames
Empfang beendet
H1-Bus
Daten
Statuswort
Recv-All
Empfangs-Auftrag
CPU
CP
Empfang beendet
H1-Frame
Daten
Receive HTB
Recv_All
Note!
Due to the large quantity of acknowledgment receipts that are transferred
via an H1 transport connection, the load on the network is appreciably
higher under H1 than under TCP/IP, however, under TCP/IP the security of
the data is reduced!
H1 - Industrial
Ethernet
