Details
PROFINET Results Fragmentation is available on DataMan readers with firmware 5.7.3 or above versions.
This feature is automatically enabled together with Results Buffering, when the Results Buffer Enable bit is set to TRUE. This splits the result string into smaller pieces to fit into the selected Results buffer module size. For example, with a Result Data size of 32 bytes, a 68-byte long result string will be split into 3 messages: 32 + 32 + 4 bytes. Then these chunks are pushed to the buffer like normal results one after the other, and the PLC can read the chunks one by one and reassemble the result string.
In contrast, if Results Buffering is disabled, large decode result strings are cut off to fit into the Result Data field, which means that the end of the string gets lost.
A decode result chunk looks like a normal result. The Result Length represents the remaining number of result characters. The last chunk of a result string can be found as follows:
- its Result Length is lower or equal to the configured Results buffer size
- its Result ID is different from the ID of the next result
You can follow the below steps to read the fragmented results in the PLC sequence:
- set Results Buffer Enable bit to TRUE
- wait for the Results Available bit to become TRUE
- read the Result Length and Result Data
- if the Result Length value is larger than the configured Results buffer module size, then there are further chunks waiting for transmitting
- set the Results Ack bit to TRUE and wait until the Results Available bit turns to FALSE
- clear the Results Ack bit
- if there are further chunks waiting for transmitting, jump to step 2
