April 26, 2012 - The Sercos user organization released the specification update for the real-time Ethernet solution Sercos III. On request by users and manufacturers, several profile and protocol extensions have been included in the sercos III specification over the last 2 years. Specification V1.3 not only broadens the functionality and the range of applications of the globally accepted real-time standard Sercos but also includes new trends in machine and plant construction. The extensions are fully compatible with the existing specification so that a high level of standardization and best possible interoperability of devices from different manufacturers can be ensured.
Following electronic drives, hydraulics and pneumatics are also 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 to support electric, hydraulic, and pneumatic drives across different technologies. Two new profiles have been added to the new Sercos specification. The energy profile defines parameters and commands to reduce energy consumption in a uniform and vendor-independent way.
Furthermore, an encoder profile was specified that provides absolute and incremental encoder interfaces to all devices in a sercos network. The following new services were specified on the protocol level: an oversampling procedure that allows acquisition of equidistant values and activation of equidistant command values – faster than the configured bus or connection cycle. This increases the process control intricacy, for instance in extremely time-critical laser applications, as it allows for more data to be collected and communicated at a faster speed. Measurement methods were integrated directly in the protocol, thereby opening up the possibility to access these mechanisms across different manufacturers and products.
In addition, a time-stamping procedure for event-triggered acquisition of values with corresponding time stamps, as well as time-triggered activation of command values, has been defined. 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, for instance in complex solutions such as those needed in semiconductor or solar manufacturing. The specification update is completed by an installation guide which specifies cabling with copper wire and optical fiber, each in compliance with the IP20 and IP65/67 protection class.
SErial Realtime COmmunication System, in short Sercos, is one of the leading digital interfaces for communication between controls, drives, and decentralized peripheral devices. Sercos has been used in machine engineering for over 20 years and is implemented in over 3.0 million real time nodes. With an open, manufacturer-independent architecture based on Ethernet, Sercos III is a universal bus for all automation solutions.