Writing a string variable of the straton_NG driver in the zenon runtime with a length of 247 characters or more fails and prevents further writes to the string variable from the zenon runtime until after a restart of the runtime

Writing a string variable of the straton_NG driver in the zenon runtime with a length of 247 characters or more fails and prevents further writes to the string variable from the zenon runtime until after a restart of the runtime

Summary

When a string variable in zenon (lenght 255) from the straton_ng driver is written in the runtime (string lenght in zenon logic 255), writing 246 characters still works OK.

However writing 247 characters is not accepted (string is not updated in the zenon logic) and any further writes to the string variable, even with just one character, no longer updates the string variable in the zenon logic. If at this stage the string variable is updated in the zenon logic, the variable is correctly updated in the zenon runtime, but it still cannot be written in the zenon runtime.

After a restart of the runtime, the string variable can be written again.

Description

When a string variable in zenon (lenght 255) from the straton_ng driver is written in the runtime (string lenght in zenon logic 255), writing 246 characters still works OK.

However writing 247 characters is not accepted (string is not updated in the zenon logic) and any further writes to the string variable, even with just one character, no longer updates the string variable in the zenon logic. If at this stage the string variable is updated in the zenon logic, the variable is correctly updated in the zenon runtime, but it still cannot be written in the zenon runtime.

After a restart of the runtime, the string variable can be written again.

Solution

Problem was addressed in the function to write variables. The maximum possible telegrammlength is now used.

Information

When using strings with the maximum length, it is recommeded to set in the connection setting of the driver the max. write request length to 1024 instead of 512

Issue Number: 31516
Fixed on Date: 6.3.2014
Versions: 7.10 0 BUILD 11355 | 7.20 0 BUILD 17768