Siemens SIMATIC NET CP 243-1, Operating Instructions Manual

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Configuration
3.2 Value ranges of the configuration data
CP 243-1
Operating Instructions, 03/2012, C79000-G8976-C244-02
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Remember that the validity of an IP address and a related subnet mask are dependent on
each other.
3.2.3 TSAPs
TSAPs consist of 2 bytes. The first byte specifies the connection. The second byte is created
from the rack number and the slot of the communications module. The following value
ranges apply to the first byte.
Range of values for the local TSAP 16#02, 16#10 - 16#FE
Range of values for the remote TSAP 16#02, 16#03, 16#10 - 16#FE
The CP 243-1 does not check the value of the second byte.
3.2.4 Ports
Each standard protocol from the TCP/IP protocol family (for example HTTP, FTP or SMTP)
is assigned to a separate fixed port number with which a related communication service can
usually be accessed in a TCP/IP network. These permanently assigned port numbers are
called "well-known" port numbers since they were specified worldwide in the definition of the
protocol. Standard protocols usually use port numbers between 0 and 1024. Port numbers
higher than 1024 are not fixed and can be assigned by the user programs as required.
Thanks to modern protection mechanisms in TCP/IP networks (for example firewalls), the
ports usually used by standard protocols are rerouted to other ports. To allow the CP 243-1
to be able to communicate with external SMTP servers even in such environments, you can
explicitly specify the port via which such a server can be accessed when you configure the e-
mail service with the Internet wizard of STEP 7 Micro/WIN 32. Standard SMTP servers can
be accessed with port 25.
3.2.5 E-mail tags
An e-mail consists of one or two address fields, a field for the subject and a field for the text
message. The text message is made up of ASCII characters. In addition to the two control
characters \n and \t, the text can also contain placeholders defining an embedded data
value. When an e-mail is sent, the CP 243-1 reads the current value of such a placeholder
from the local S7-200 CPU, formats it and inserts it in the message.
Such placeholders use the following syntax:
%address:places_before_decimal_point.places_after_decimal_pointFormat%