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A question on AM1810 DP data loss

Other Parts Discussed in Thread: AM1810, PROFIBUS
Hi TI engineers!
Here is another question my team is facing now. 
AM1810: Linux 2.6.33.7-rt29
DP: DPSlave_EVAL in am181x_profibus_dpslave_app-04.01.00.00
PLC  Profibus Master communicates with AM1810  PROFIBUS  slave within a period of 20 ms. DP slave station can work normally when there is no other Linux application program works. But when other program works, such as ntupdate for timing or Web access to AM1810 module, data loss will occasionally happen to DP slave. The time will last several to decades of periods and thus DPSlave_EVAL real-time performance will suffer to some extent. But this phenomenon doesn't happen everytimen when our engineers start such programs.
So, how to ensure DPSlave_EVAL to work real-time without being affected by other such programs' functioning? It is a safety issue for our controlling system and thus we want to avoid from this kind of DP data loss.
Thank you very much.
Guotao
 
  • Hi,
    Able to avoid the data loss when you increase the time 20ms to some higher ?

    But when other program works, such as ntupdate for timing or Web access to AM1810 module, data loss will occasionally happen to DP slave.

    What do you mean "other program" ?
    What stuff it has in that program ?
    Could you check the CPU memory access with "top" command when you run CAN as well as program.
  • Hi thanks for your quick reply. This question does not matter with CAN, but only DP. The data exchange frequency between DP slave and PLC master station is 50 Hz(20 ms). We use DP to transfer our control commands from AM1810 module to PLC and then PLC feeds back the result. The same procedure for the next round. It can function very well within the above.

    "Other program" means those are not necessarily used for functioning DP data exchange or algorithm calculation or power management etc.. in AM1810. For example, you don't often need to synchronize the AM1810 module with internet time or you don't often need log into the module to have a look at the system version by Web server.

    But we found the operation such as time synchronization under the condition of PLC/AM1810 working would make the data exchange between PLC master and AM1810 slave get lost for several and even decades of periods (yes, the unit is 20 ms and the time for no data exchange is up to 20 seconds). But sometimes time synchronization doesn't affect at all.

    We think external operation can be isolated from the inner system operation. How to deal with it?

    I hope you get my meaning:)

    Thank you very much.

    Guotao
  • Hi Everyone! Anyone updating this question?