LIGO Document E1300442-v1
- This library provides the basic encoding to send data between the EtherCAT system and the real-time system. The encoding uses 16 levels per line. Multiple lines can be ganged together. The library uses 1 bit internally for a keep-alive signal. The library also checks for multi-bit consistency. If the keep-alive is missing for 10 consecutive seconds, a communication lost error is raised. If multi-bit consistency could not be achieved with the last second, a communication reject error is raised. A configuration error is raise, if the number of input or output lines is not between 1 and 8.
The keep-alive bit is toggled every 100 ms. Up to 8 hardware lines are supported in each direction. At least one line must be provided in each direction. This yields a total of 32 bits, where up to 31 bits are available to the user. The input and output data words are filled starting with the LSB.
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