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Industrial Ethernet S7-300/400 CPs -- Setting up and parameterizing hardware -- Initializing and parameterizing modules
Why is there no entry with the current firmware version for my module in the STEP 7 hardware catalog?
What should you watch out for when a MAC address is entered for the PROFINET interface or GBIT interface in the configuration of the Industrial Ethernet CP343-1/CP443-1?
How do you configure a shared device when you are using a CPx43-1 Advanced as PROFINET IO controller and the GBIT interface of the module is networked?
Which "local_device_id" do you parameterize in order to establish a connection to FB65 "TCON" for open communication via Industrial Ethernet?
Which Industrial Ethernet CPs support the DHCP Option 12 (Host Name) and how do you configure the DHCP Option 12?
What should you watch out for when parameterizing the watchdog time when a ring redundancy is established with the Media Redundancy Protocol?
How do you use an Industrial Ethernet CP or SCALANCE S as a gateway?
How do you disable the "Link Layer Discovery Protocol" function at the ports of an IE CP of S7-300 or S7-400?
Where can you find sample S7 programs and documentation for communication via gateways and network components, and for security in networks on the SIMATIC NET Quick Start Collection?
What should you watch out for when operating a CP443-1EX20 V2.0 on a CPU V5.1?
Changing the configuration data of users for CP 343-1 IT and CP 443-1 IT
Loading the configuration via LAN into the IE-CP in "STOP" mode
Special points when setting the LAN medium for Industrial Ethernet CPs
Starting up automation systems with Industrial Ethernet without previous node initiation via MPI
Rejected diagnostics connection via TCP/IP protocol after changing the MAC address
Establishing an online connection to an S7-300/S7-400 CPU through several Ethernet interfaces
What should you pay attention to when formatting the file system in the S7-300 and S7-400 Industrial Ethernet CPs?
What should you watch out for when replacing the CP443-1 (6GK7443-1EX11-0XE0) with a CP443-1 (6GK7443-1EX20-0XE0 V1.0) in STEP 7 V5.4 SP3?
What is the meaning of the configuration option "Activate Web server" with CP443-1 EX20?
Why with CP443-1 Advanced is a different firmware version than the module displayed in the C-PLUG info text in the NCM S7 Diagnostics?
Which options are available for assigning the PROFINET IO controller a new IP address?
How can you configure an S7 CP during runtime?
How do you disable the S7 routing functions?
Which manufacturer ID, in other words OUI (Organizationally Unique Identifier), does SIEMENS AG use for the MAC addresses of network-compatible devices?
How can you protect the S7-300/400 against unauthorized access from the LAN (local area network)?
What should you watch out for when using the function block FB55 "IP_CONFIG" to configure an Industrial Ethernet CP?
Why are some of the newer versions of the names of SIMATIC NET modules not used in the hardware catalog?
Why can't my SIMATIC S7-300 Ethernet CP run as many S7 communication connections as specified?
How does connection multiplexing work and how do you configure it for SIMATIC S7-300 Ethernet CPs?
Special points when setting the LAN medium for Industrial Ethernet CPs
Part number:

What do I have to watch out for when using the fixed settings of the LAN medium for Industrial Ethernet CP?

The information given below applies for the following Industrial Ethernet communications processors:

  • CP 343-1 A2 (6GK7 343-1EX10-0XE0)
  • CP 343-1 IT (6GK7 343-1GX00-0XE0)
  • CP 443-1 A2 (6GK7 443-1EX10-0XE0)
  • CP 443-1 IT (6GK7 443-1GX10-0XE0)

These multiprotocol CPs support a data transfer rate both of 10 Mbps (Ethernet) and of 100 Mbps (Fast Ethernet).
If you connect such a CP to a network component, then normally the transfer rate is "negotiated" automatically by the users concerned via the autonegotiation mechanism. Here both the data transfer rate (10 Mbps or 100 Mbps) and the operating mode (half duplex or full duplex).

  • Half duplex: the data exchange can be bidirectional. On one transfer route between two components there is always only one data transport possible in one direction at one time.
    Example: if a message is sent from A to B, then user B can only send a message to A when user A has terminated its send process.
  • Full duplex: the data exchange can be bidirectional. On one transfer route between two components each of the two users can send independently from each other.
    Messages can be sent simultaneously from A to B and vice versa. There is a separate line pair for each send direction.

If one of the users does not support the autonegotiation mechanism, the partner sets the default operating mode (10 Mbps and half duplex).

If you implement components which support the transmission type 10 Mbps, full duplex but not the autonegotiation function, then you can set the full duplex operating mode by hand.

Example: OSM_V1 (Optical Switch Module)
With this network component the operating mode can be permanently set. If you link an OSM_V1 with one of the above-mentioned CPs, the CP sets itself to the transmission mode 10 Mbps - half duplex, because the OSM_V1 doesn't support autonegotiation.

Fixed setting of the LAN medium:
The LAN medium can be set in the hardware configuration of the CP under "Properties" in the "Options". This is illustrated by the relevant configuration window below:

The default value after inserting the CP is "Automatic setting". As an option you can permanently set any operating mode. The CP adapts to the operating mode set and does not do an autonegotiation.
You must be careful with the permanent setting.

A direct link between two of the above-listed modules is used. Here you connect the two communications processors without network components using a "crossed" cable. You set the setting of the LAN medium on one of the two CPs to "Automatic setting" and to "10 Mbps - full duplex" as a fixed setting on the partner CP. Then both CPs are activated in the relevant S7 stations.


  1. The CP with the fixed setting will set itself as requested to "10 Mbps - full duplex".
    However at startup it doesn't start the autonegotiation mechanism and does not react to an attempted autonegotiation from the partner CP.
  2. The CP with the automatic setting will attempt to negotiate the operating mode through autonegotiation. In any case it doesn't get any response from the partner (which is permanently set). As a consequence it sets its LAN operating mode to the default operating mode of "10 Mbps - half duplex".

The setting finally selected by the communications processor can be read in the NCM diagnostics in the diagnostics buffer of the CP. In addition the selected operating mode is indicated by the LEDs on the front of the CP.

Diagnostics buffer of the CP with the fixed setting:
The marked entry clearly shows the settings selected: "Fixed Setting - 10 Mbps - full duplex".

Diagnostics buffer of the CP with the automatic setting:
The same for the partner CP: "Automatic setting - 10 Mbps - half duplex".

The two linked terminal devices are now working with different LAN operating modes. This results in an increased number of collisions. These collisions cause a vast number of message repeats. Depending on the frequency these can lead to connection interruptions and thus to impaired performance.

Take great care when using the fixed setting. Normally the automatic setting is sufficient, because the components concerned then agree upon the maximum possible operating mode. If you still want to operate the modules listed above with a fixed setting, then always select the same fixed setting for each partner.

 Entry ID:2289386   Date:2000-05-23 
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