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03/03
2.2
S7 Communication via Industrial Ethernet
2.2.1
Preliminary Comments
S7 communication via Industrial Ethernet permits program-controlled communica-
tion via communication SFBs/FBs and configured S7 connections. The CP 243-1
IT supports S7 communication via Industrial Ethernet with the XPUT/XGET and
READ/WRITE services. Up to 212 bytes of user data can generally be transmitted
per job. If the CP 243-1 IT is run as server, up to 222 bytes of user data can even
be transferred in read jobs.
The CP 243-1 IT supports a maximum of eight S7 communication channels to cli-
ents or servers on one or more geographically removed communication partners.
The CP 243-1 IT works on the client/serve principle for each channel. Only one job
at a time per channel is accepted, processed and answered with a positive or
negative response. Not until a response has been sent does the CP 243-1 IT ac-
cept a new job.
If the CP 243-1 IT receives several jobs on a channel configured as server, only
the first job is processed. The subsequent jobs are ignored until the end of the
transaction (i.e., until a response is sent). The CP 243-1 IT has no channel-specific
job administration and does not buffer jobs.
Prerequisites for communication with a PC/PG
As before, a PG/PC can access the S7-200 CPU via the PPI interface. In addition,
this access may take place via the CP 243-1 IT via Ethernet. The following prereq-
uisites must be fulfilled for this.
• An Ethernet card is installed and configured on the PG/PC and an Ethernet or
TCP/IP connection to the CP 243-1 IT exists (via routers, firewalls, and so on).
• STEP 7 Micro/WIN 32 (starting with version 3.2.3) is installed on the PG/PC.
• The CP 243-1 IT has a valid address. This address may be permanently speci-
fied in the configuration or obtained from a BOOTP server.
At this time, only one STEP 7 Micro/WIN 32 can communicate via a CP 243-1 IT
with the S7-200 CPU. Use of the Ethernet interface is mandatory for configuration
of the IT services.
CP 243-1 IT
J31069-D0429-U001-A0-7618
Features and Functions
17
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