| Accelerator Controls & Beam Diagnostics Division |
| Serial Communication Analyzer for Indus Control System |
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Indus-1 & Indus-2, Synchrotron Light Sources has dedicated supervisory control systems interfaced to various sub-systems distributed over a large area. Control system communicates with the remotely located field controllers over RS485 Serial Bus to control the important machine parameters to accomplish its desired performance. An industry standard Profibus communication protocol is implemented to interact with these field controllers. Performance of serial bus communication has vital role in monitoring and control of synchrotron beam parameters for reliable and uninterrupted delivery of beam to beam-line users.
A prototype serial communication analyzer system is developed which detects the communication errors at protocol and signal level. This system continuously monitors the data over these serial buses, which are transmitted in the form of electrical voltages at maximum 1Mbps, records and validates them in real-time.
This system consists of a High-speed data-acquisition system (fig. 1), which captures and stores the actual voltages of RS485 serial bus at 10MSPS of 12-bit resolution (fig. 2) and stores an event of ~6.4ms data. A signature based analysis module which measures and records the time profile of various transmission packets (telegrams) with a time resolution of 1 µs (fig. 3). Retrieval of digitized data of RS485 line voltage signals is done in synchronism with configurable event generated by signature based analyses module. Software is developed to identify and classify the type of communication errors like Start Delimiter Error, frame length, Frame Checksum Error, Parity Error etc.
This system has the flexibility of configuring it to either a generalized protocol analyzer or a specific user defined diagnostic and analysis.
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| Fig. 1 : High-speed Data-acquisition |
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| Fig. 2 : Command-Response Telegram Electrical Voltages Captured |
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| Fig. 3 : Signature Based Packet Analysis of Communication Protocol |
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