Available as free open source software, the Sercos SoftMaster is a software-based Sercos Industrial Ethernet master that is implemented on standard industrial-PC hardware (X86 or ARM) with support for a variety of operating systems. Dedicated hardware is not required, providing cost savings in many applications.
Bosch Rexroth has made the Sercos SoftMaster available as free open source software on SourceForge.net. They also offer a free Sercos-on-a-Stick livesystem--a complete stand-alone demo Sercos driver package on a USB thumb drive. This includes the SoftMaster based on INtime® Distributed RTOS from TenAsys Corporation, and a test application. This is the Sercans XS package, available on request from [email protected]
The solution is scalable:
- A standard Ethernet controller with a suitable real-time operating system is sufficient for all entry-level solutions with bus cycle times of >= 500µs, a line topology, and microsecond-range synchronicity between the system components. It is estimated that this applies to at least 50% of potential applications.
- For medium to high synchronicity requirements in the range of <100ns jitter and bus cycle times >=125µs (which covers virtually all applications), the use of a TTS-capable Ethernet controller (such as the Intel I210) together with a suitable real-time operating system offers an excellent solution. If two of these Ethernet controllers are synchronized, the support of ring architecture with seamless redundancy is also possible.
The familiar Sercos HardMaster solutions are still available for all applications with higher bus cycle time requirements, or for which the hardware and operating system platform requirements cannot be met.
Using the generic mode, virtually every Ethernet controller is suitable for use with the Sercos SoftMaster. However, the telegram jitter reduces the synchronization accuracy. For higher synchronicity and cycle time requirements, the NIC/TTS mode (as with Intel I210) is available. Here, the Ethernet controller (NIC) precisely determines the telegram transmission using its own timer. Software-based timing disturbances (jitter) are eliminated as programs must only ensure that telegram content is fed to the Etherrnet controller within the time window provided.