| April 6, 2012
Networking: Ethernet Based Sercos III Specification Updated to V1.3
The Sercos vendor organizations have released an update to the specification for the Sercos III Real-time Ethernet solution.
The V1.3 specification broadens the functionality and the range of applications of the international Sercos real-time standard, while considering new trends in machine and plant construction. The extensions are fully compatible with the existing specification so that the high level of standardization and the best possible interoperability of devices from different manufacturers can be ensured.
Following the lead of electronic drives, hydraulics and pneumatics are turning more and more towards digitally controlled modules. This increases flexibility and shifts tasks previously solved by mechanical means to software solutions. The Sercos organization recognizes the importance of this trend and has extended the existing Sercos drive profile such that electric, hydraulic and pneumatic drives now are supported across different technologies.
Two new profiles have been added to the Sercos specification. The energy profile defines parameters and commands for the reduction of the energy consumption in a uniform and vendor-independent manner. An encoder profile makes the interface of absolute and incremental encoders available to all devices on a Sercos network.
The following new services are specified at the protocol level: oversampling and time-stamping. The oversampling procedure allows the acquisition and transmission of equidistant values faster than the configured bus or connection cycle. This increases the process control intricacy in extremely time-critical applications, such as laser applications, because it allows more data to be collected and command values to be communicated at a faster speed. Measurement methods are integrated directly into the protocol, thereby making it possible to access these mechanisms across different manufacturers and independently of the product.
In addition, the specification defines a time-stamping procedure for the event-triggered acquisition of values with corresponding time stamps, as well as the time-triggered activation of command values. This function is event-controlled, promptly transmitting defined events such as certain measurement values to the controller and switching outputs independently from the clock cycle. This increases process stability in complex solutions such as those needed in semiconductor or solar manufacturing.
The specification update is completed by an installation guide that specifies cabling with copper wire and optical fiber, each in consideration of IP20 and IP65/67 protection classes.
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