Anybus CompactCom Sync and PROFINET Isochronous Mode
The sync functionality is described differently in the PROFINET network specification than how it is described in the specification for Anybus CompactCom in general. See the Anybus CompactCom 40 Software Design Guide for a detailed description of the Anybus CompactCom sync functionality.
This section describes the correlation between the specifications.
The figure below shows a timing diagram for PROFINET isochronous mode.
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T_IO_OutputMin
T_IO_OutputMin consists of two delays:
The delay added by the Anybus CompactCom. This is the time from when the message is available on the network until it is available to the application. This delay is 0 in the current implementation.
The delay added by the application. This is the time it takes for the application from when it is notified that new process data has arrived, to when the process data is copied and the output is valid. This delay must be measured by the application designer. The measured value shall be written to Attribute #4 (Output Processing).
The value of T_IO_OutputMin must be entered in the GSD file for every submodule supporting synchronous operation. See example GSD entries below.
T_IO_InputMin
T_IO_InputMin consists of two delays:
The delay added by the Anybus CompactCom. This is the time from when the message is available in the device until it is available on the network. This delay is 12 μs in the current implementation.
The delay added by the application. This is the time it takes for the application from when inputs are captured, to when the input data is available to the Anybus CompactCom. This delay must be measured by the application designer. The measured value shall be written to Attribute #5 (Input Processing).
The value of T_IO_InputMin must be entered in the GSD file for every submodule supporting synchronous operation. See example GSD entries below.
T_IO_Output
T_IO_Output is equivalent to attribute #2 (Output Valid). The value is configured from the IO controller.
T_IO_Input
T_IO_Input is the configured Cycle Time (T_DC) minus the Input Capture time (Attribute #3). The value is configured from the IO controller.
T_DC
T_DC = Cycle Time (Attribute #1)