Many applications require a quick response time via the distributed inputs and outputs. Apart from the PROFIBUS DP, SIMATIC also uses the PROFINET IO for quick and efficient data exchange between distributed I/O and S7 stations. With PROFINET IO, the Industrial Ethernet technology has now been introduced to the field level.
Typical PROFINET IO configurations consist of an IO controller with several IO devices, while additional loads such as programming devices (PG) or operator panels (OPs) or even additional S7 stations are used as data receiving stations on the Industrial Ethernet.
One of the most important questions arising in the course of configuration design refers to the response times to be expected. It is mainly important when refitting from existing PROFIBUS DP systems to PROFINET IO:
- How long does it take until a distributed output responds to a distributed input when
- the processing is performed via the cyclic process image in OB1?
- processing is performed via direct commands and the process alarm (OB40)?
- processing is performed via a clock-synchronized interrupt (OB61)?
- What fluctuations can occur?
- What impact do IWLAN routes have?
- To what extent does communication via PROFINET IO have an influence on the cycle time of the IO controller?
- What update/operating time must be expected for the parallel operation of a panel on the controller?
- What influence does a parallel cross-communication via various protocols (S7 communication, TCP/IP communication) have on the response time on the PN IO line?
With the use of Panel PCs, some further questions arise:
- How do the response times behave, if a WinAC RTX as well as a WinCC flexible Runtime configuration run on a PanelPC?
- What are the effects of a WinCC flexible Runtime configuration of a PanelPC on the times of additional TouchPanels?
The following screen shows the schematic layout of the measurement on a variant:
To answer the above questions, Industry Automation and Customer Services carried out extensive measurements on typical configurations with SIMATIC components, which provide planning certainty for your plants:
- Various IO controllers communicate with up to 60 I/O devices.
- As an alternative, a programming device or up to 7 touch panels can be operated at the PN line of the IO controller.
- The IO controller runs with a typical user program. In the programming device, the State function is active.
- The IO controller can be cable-based if desired or connected via an IWLAN route or an IE/PB link with the distributed I/O.
- Parallel to the IO communication a data communication of up to 8 receive S7 stations can take place.
- The WinAC RTX and WinCC flexible Runtime configurations are simultaneously operated on a PanelPC.
A simple user interface of a web application provides you with the results of the measurements.
Overview of the measured variables:
|PN response time (OB1)
||Time from receiving a process signal at the input of the ET200 until activation of an output at the ET200 (via process image).|
|PN response time (OB40)
||Time from receiving a process signal at the input of the ET200 until the activation of an output at the ET200 (via process-alarm and direct commands).|
|PN response time (OB61)
||Time from receiving a process signal at the input of the ET200 until activation of an output at the ET200 (via partial process image in the clock-synchronized OB61).|
||Time between two process image transfers in the IO controller.|
|PNIO update time
||Time between two I/O cycles of the IO controller (calculated by STEP 7).|
|Data transfer time
||Time between a send trigger for data transfer on the IO controller and the acknowledgement receipt of the last receive CPU.|
|HMI update time
||Time from receiving a process signal at the input of the ET200 until the response of the visualization interfaces on the panel|
|HMI operating time
||Time between an operator action on the panel interface until activation of an output of the ET200 station|
|PPC update time
||Time from receiving a process signal at the input of the ET200 until the response of the visualization interfaces on the Panel PC (with WinAC RTX)|
|PPC operating time
||Time between an operator action on the Panel PC (with WinAC RTX) until activation of an output of the ET200 station|
Measurement was performed for some typical configurations. This does not mean that every possible configuration has been measured.
Outputs on the user interface
An interactive user interface enables you to quickly and easily enter your desired configuration. The values measured for the selected configuration are immediately displayed in the table of performance data. In addition the data can be downloaded in Excel format.
Access to the performance data
Click the respective version to go to the web interface of the performance data.
Integration of CPU 1215C