ZCOM Message Handling

Error Handling

Error Handling

In the normal functioning of ZCOM, transmission errors on messages to terminal ZLUs are handled by the Mux interface card firmware. The firmware always sends a status back to the driver after it has processed a request - retries are handled internally. The driver checks the mode of the send (i. e., send no wait, report errors, etc.) to determine what to pass back to the requesting program.

If a power failure occurs or the Mux interface card crashes, the driver receives an interrupt from the operating system. This interrupt causes the driver to send a request to ZMON to download the firmware to the particular interface card and to perform a full restart sequence (which also involves re-sending any unacknowledged messages). If the directory /var/opt/acc/dmp exists, ZCOM will upload the contents of the Mux card memory and store it in a file in this directory whenever a Mux card failure is detected. This provides the ability to analyze firmware failures which can be particularly valuable during the development of custom protocols.

For a detailed description of ZCOM C interface routine error codes, please refer to the ACC Error Guide.

Chapter 2

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