Communication
11.2 PROFINET
S7-1200 Programmable controller
824 System Manual, V4.2, 09/2016, A5E02486680-AK
PROFINET device start-up time, naming, and address assignment
PROFINET IO can extend the start-up time for your system (configurable time-out). More
devices and slow devices impact the amount of time it takes to switch to RUN.
In V4.0 and later, you can have a maximum of 16 PROFINET IO devices on your S7-1200
PROFINET network.
Each station (or IO device) starts up independently on start-up, and this affects the overall
CPU start-up time. If you set the configurable time-out too low, there may not be a sufficient
overall CPU start-up time for all stations to complete start-up. If this situation occurs, false
station errors will result.
In the CPU Properties under "Startup", you can find the "Parameter assignment time for
distributed I/O" (time-out). The default configurable time-out is 60,000 ms (1 minute); the
user can configure this time.
PROFINET device naming and addressing in STEP 7
All PROFINET devices
have a Device Name and an IP Address. Use STEP 7 to define
the Device Names and to configure the IP addresses. Device names are downloaded to the
IO devices using PROFINET DCP (Discovery and Configuration Protocol).
PROFINET address assignment at system start-up
The controller broadcasts the names of the devices to the network, and the devices respond
with their MAC addresses. The controller then assigns an IP address to the device using
PROFINET DCP protocol:
● If the MAC address has a configured IP address, then the station performs start-up.
● If the MAC address does not have a configured IP address, STEP 7 assigns the address
that is configured in the project, and the station then performs start-up.
● If there is a problem with this process, a station error occurs and no start-up takes place.
This situation causes the configurable time-out value to be exceeded.
To Next Page
Loading...
