The ET 200M modular I/O station consists of:

• one IM 153 interface module
• up to 8 I/O modules of the S7-300 automation system and
• a power supply unit if required.

No specific slots are assigned to the I/O modules. Any combination of modules is possible.

The ET 200M is connected to the PROFIBUS DP via an IM 153 interface module. Fiber-optic connection to PROFIBUS DP is possible through integrated interfaces on the IM 153-2 FO or through an additional OLM (Optical Link Module) or OBT (Optical Bus Terminal).

Various types of I/O modules can be plugged in depending on the quantity framework of the master module.

The full address area of the ET 200M can only be used with a suitable master.

 Configuration with bus connectors

The SIMATIC S7-300's simple construction using bus connectors makes the ET 200M flexible and service friendly:

• Module assembly; simply hang the modules onto the DIN rail, swing them down and tighten the screws.
• Integrated backplane bus; the backplane bus has been integrated into the modules. Interfacing with the modules is through bus connectors which are inserted into the rear of the housing.

Configuration with active bus modules

The active bus modules permit changing of modules during operation:

• Time-saving module replacement; it is not necessary to interrupt operation when changing modules; the system continues with the remaining modules. When the new module is plugged in, it is automatically started up. With an S7-400 as master, removing/plugging in of a distributed module is treated like the removing/plugging in of a centrally configured module. A corresponding interrupt is generated in the CPU. With all other DP standard masters, a signal is transmitted to the master through DP diagnostics. Hot swapping of modules during normal operation is not supported with a S7-300 as a master.

There are various bus modules available for configuring the ET 200M. These are mounted on special rails:

• BM PS/ IM bus module for power supply and IM 153
• For redundant mode two IM 153-2 (FO) can be mounted on the BM IM153/IM153 bus module.
• BM 2x40 bus module for 2 I/O modules with 40 mm width
• BM 1 x 80 bus module for 1 I/O module with 80 mm width

To obtain the required thread length, an Ex barrier is available as an accessory that can be inserted between each bus module.

• Easy assembly The bus modules are swung onto the DIN rail, butted side to side and secured with lateral plug-in connectors. The modules can then be swung onto the bus modules and screwed into position establishing contact with the bus module connector. The connectors of unoccupied slots must be protected with backplane bus covers. A bus module cover is inserted into the side of the last bus module.

Power supply

Single phase 2 A, 5 A and 10 A power supplies are available as special versions for the ET 200M.

Operating mode

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.