Principle of operation

The inputs and outputs of the modular ET 200M I/O station can be accessed from the user program in the PLC in the same manner as the inputs and outputs of the central controller.

Communication through the bus system is handled completely by the master interface module in the central controller and the IM 153 interface module.

Proper operation of the ET 200M is verified by way of diagnostic functions.

The ET 200M diagnoses:

• Module faults
• Short circuits (outputs)
• Bus errors, i.e. faulty data transfer
• 24 V DC load voltage supply
• Plugging and removal of I/O modules

The diagnostic data are analyzed as follows:

• Remotely through diagnostic LEDs on the ET 200M
• Centrally via the CPU in the programmable controller.

Configuration and parameterization

Calculating the frame length required for the configuration and parameter assignment frame

The DP master must provide the required quantity of configuration and parameterization data. A few masters have a restricted configuration and parameterization frame length. On the S5-95U/DP, for example, the maximum length of the configuration and parameterization frame is 32 byte. This means that in this example up to 3 modules, one of which may be parameterizable, can be plugged into the ET 200M.

When the station is connected to master modules which are not parameterized with COM PROFIBUS or STEP 7 (operation on third-party master modules), a fixed preassigned GSD file can be created with COM PROFIBUS from Version 3. This file is then loaded into the configuration tool of the third-party manufacturer and can be used for simple parameter assignment of the station.

This allows the use of the user-friendly plain-text parameterization feature of COM PROFIBUS; there is no need for hexadecimal code inputs in the third-party configuring tool.

To be able to use the entire address area of the IM 153, a suitable master is required.