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Entry type: FAQ Entry ID: 44383954, Entry date: 01/04/2022

Which IO controllers and IO devices support the following functions in STEP 7 V5.x: IRT, prioritized startup, MRP, MRPD, PROFIenergy, Shared device, I device, sochronous mode, System redundancy and Option handling?

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In an overview is shown which PROFINET functions are supported by the PROFINET IO controllers and IO devices in STEP 7 V5.x.

The PROFINET IO controllers below support the above-mentioned PROFINET functions in STEP 7 V5.x.

 Registrierung notwendig  IO-Controller_PROFINET_functions_en.xlsx (36,7 KB)

The PROFINET IO devices below support the above-mentioned PROFINET functions in STEP 7 V5.x.

 Login required  IO-Device_PROFINET_functions_en.xlsx (31,8 KB)

The Entry ID 49311792 gives you an overview of the PROFINET IO controllers and IO devices of SIMOTION and SINAMICS that support the PROFINET functions above.

Isochronous real-time communication (IRT)

Synchronized transmission procedure for cyclic exchange of IRT data between PROFINET devices. There is a bandwidth reserved for the IRT data in the transmitter clock. The reserved bandwidth guarantees that the IRT data can be transmitted at reserved, clock-synchronized intervals even when the network is otherwise heavily loaded (with TCP/IP communication or additional real-time communication, for example).

Prioritized startup

Prioritized startup is the PROFINET functionality for accelerating the startup of an IO device in a PROFINET IO system with RT and IRT communication.

The function cuts the time needed by the appropriately configured IO devices to get back into the cyclic user data communication in the cases below:

  • After return of power supply
  • After station return
  • After IO device enabling

Media Redundancy Protocol (MRP)

Medium redundancy is a function for ensuring that availability of networks and plants. Redundant transmission paths (ring topology) ensure that when one transmission path fails an alternative path is made available.

Media Redundancy with Planned Duplication (MRPD)

If media redundancy is to be achieved with short update times (together with IRT), you must use the MRP add-on "Media Redundancy with Planned Duplication" (MRPD). MRPD is based on IRT with "high performance" and MRP. To realize media redundancy with short update times, the PROFINET devices participating in the ring send their data in both directions. The devices receive this data on both ring ports, eliminating the ring's reconfiguration time. As with MRP, the redundancy manger prevents circling data frames.


Function for saving power in the process, during idle times, for example, through temporary switch-off of the encoder and load supply in the potential group via standard PROFIenergy commands.

More information about PROFIenergy is available in the manuals ready for downloading in the Entry IDs below.

ManualDescription Entry ID 
SIMATIC PROFINET System DescriptionGeneral information about PROFIenergy19292127 
SIMATIC S7-300 with PROFINET interfacePROFINET IO Controller or IO Device with PROFIenergy12996906 
System and Standard Functions for S7-300/400
Volume 1 and Volume 2

Send and receive (PROFIenergy) data records

  • With SFB73 "RCVREC" you receive the (PROFIenergy) data records in the I device of the higher-level IO controller.
  • With SFB74 "PRVREC" you make the (PROFIenergy) data records in the I device available to the higher-level IO controller.
SIMATIC HMI Comfort PanelsControl of the backlight of the operator panel with PROFIenergy49313233 
SIMATIC ET 200S: Power module PM-ESwitch-off of the potential group by means of PROFIenergy43582121 
SENTRON PAC3200 / PAC4200Incorporation of the SENTRON PAC multifunctional measuring device in PROFINET and PROFIenergy with the SENTRON SWITCHED ETHERNET PROFINET module26504372 
SIRIUS motor starter M200D
PROFIenergy with motor starter M200D38823402 
ET 200S motor starter, fail-safe motor starter, safety engineering
  • PROFIenergy with DPV1 starter
  • Switch-off of the motor and measurement of the current motor current with PROFIenergy
ET 200pro motor starterPROFIenergy with motor starter
ET 200pro

Table 1

Shared device

IO device that makes its data available to multiple IO controllers.

Module-internal shared input/shared output (MSI/MSO)

The module-internal shared input (MSI) function allows an input module to make its input data available to up to four IO controllers. Each controller has read access to the same channels.
The module-internal shared output (MSO) function allows an output module to make its output data available to up to four IO controllers. An IO controller has write access to the channels of the output module. Up to three IO controllers can additionally have read-access to the channels.

I device

The "I device" (intelligent IO device) function of a CPU permits you to exchange data deterministically with an IO controller and thus use the CPU as intelligent processing unit, for example. As IO device the I device is connected to a "higher-level" IO controller.

The processing is ensured by the user program in the CPU. The process values captured in a central or remote IO are preprocessed by the user program and made available to a higher-level station over the IO device interface of the CPU or CP.

On a PROFINET interface, an I device can also be an IO controller in addition to its role as IO device, depending on the configuration.
In this way the I device can be part of a higher-level IO system through its PROFINET interface and establish a lower-level IO system as IO controller.
An I device can also be used as a shared device.

Isochronous mode for process data

Process data, transmission cycle via PROFINET IO and user program are synchronized with each other to achieve the highest deterministics. The input and output data of distributed IOs in the plant is captured and output simultaneously. The equidistant PROFINET IO cycle is the clock for this.

System redundancy

System redundancy is the connection of IO devices via PROFINET with a communication connection between each IO device and each of the two fault-tolerant CPUs. This communication connection can be set up using any topological interconnection.

Contrary to a one-sided connection of IO devices, the failure of a CPU does not result in the failure of the IO devices connected with this CPU.

Configuration control (option handling)

Configuration control allows you to prepare your automation system for future expansions or changes. Configuration control means you can configure the planned maximum expansion of your automation system in advance and flexibly vary it later by means of the user program.

We distinguish between the following procedures:

  • Configuration control with empty slots (option handling)
  • Configuration control without empty slots (option handling)
  • Expanding configuration (step-by-step commisioning)

Further Information
The Entry-ID 102325771 shows which IO controller and IO devices support the following functions in STEP 7 (TIA Portal):

  • IRT
  • prioritized startup
  • MRP
  • MRPD
  • PROFIenergy
  • Shared device
  • I device
  • Isochronous mode
  • System redundancy
  • Option handling
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