Siemens SIMATIC NET CP 243-1, Руководство по эксплуатации

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Application and properties
1.10 Safety
CP 243-1
Operating Instructions, 03/2012, C79000-G8976-C244-02
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When you save a configuration for the CP 243-1, STEP 7 Micro/WIN 32 calculates a CRC
checksum. This checksum is stored together with one part of the configuration. While
reading out the part of the configuration stored on the S7-200 CPU, the CP 243-1 checks
this checksum so that it can detect undesired changes in the stored configuration data.
This CRC mechanism can, however, also be deactivated. The configuration can then be
changed manually or by an S7-200 user program.
NOTICE
Since, after the CRC check is disabled, the CP 243-1 is no longer able to check the
configuration data for consistency in terms of desired or undesired changes, there is no
guarantee that the CP or the components connected to the network will function correctly.
NOTICE
The CP 243-1 recognizes that the CRC is disabled by a special value of a byte in its
configuration. If this value is set in the configuration either accidentally or intentionally, this
will disable the CRC check. This is why we strongly recommend that you only create the
configuration with the Internet wizard integrated in STEP 7 Micro/WIN 32 and check the S7-
200 program for memory operations that affect in the data area in which the configuration
data of the CP 243-1 is stored.
1.10.2 Data security
The CP 243-1 represents a physical connection between the Internet, Ethernet and the S7-
200 bus. It provides:
●
No protection against intended or accidental manipulation of the data areas and/or
system states of the local or remote CPUs
● No firewall functionality
Internet access by the CP 243-1 to data stored on the S7-200 CPU is possible but always
harbors the risk of misuse. For this reason, it is a good idea to change the passwords
assigned to the various users at regular intervals.
Additional information on the subject of security can be found in the document "Data Security
in Industrial Communication".
The CP 243-1 terminates an active STEP 7 Micro/WIN 32 connection when no STEP 7
Micro/WIN request was sent to the CPU for a period of 60 seconds. This prevents the
Micro/WIN server on the CP 243-1 from being blocked by network errors which would in turn
prevent a new connection to STEP 7 Micro/WIN 32.
Note
Access by the server to the S7-200 CPU via the CP 243-1 is possible both in CPU RUN and
STOP mode. In STOP mode, however, program variables or I/O values are not updated.