LP-AM243: How to improve Modbus TCP server response time performance?

Bayu Eko

Part Number: LP-AM243

I have a requirement to use a Modbus TCP server on our AM243. I have already tested Modbus TCP and it is working, but I’m wondering if I can improve the response time performance of the server.

According to the Modbus TCP server documentation, the response time is greater than 200 ms. In my application, I need to reduce the response time as much as possible. Is it possible to achieve a response time in the range of 1–10 ms?

Thank you

Best Regards

6 months ago

0 Christof Vogt 6 months ago

TI__Intellectual 790 points

Hello,

the datasheet values here are very pessimistic and need to be updated from our side.

The response time mainly depends on what else your system is doing. In a normal enviornment 1-10ms are no problem.

Regards

Christof

0 Bayu Eko 6 months ago in reply to Christof Vogt

Prodigy 121 points

I’m using ind_comms_sdk_am243x_2025_00_00_08, and so far the response is very slow. I’m only reading two discrete inputs (2 bytes each) and writing two multiple-coil registers (2 bytes each). Could you elaborate on which SDK supports a 1–10 ms response time?

By the way, do you know how to measure response time on ind_comms_sdk_am243x_2025_00_00_08?

0 Christof Vogt 6 months ago in reply to Bayu Eko

TI__Intellectual 790 points

Is it possible that you share a wireshark dump for this?

Regards

Christof

0 Christof Vogt 6 months ago in reply to Christof Vogt

TI__Intellectual 790 points

We have in the meanwhile checked the behavior and could reproduce it.

The issue is a missing flush on tcp_write. This is part of our lib and we consider the fix in our next release. Response times with that are < 1ms.

In the meanwhile you can use as workaround a customized LWIP. Add "#define TCP_TMR_INTERVAL 10" to the lwipopts.h and recompile it. This should force a faster flushing of the buffer and increase the response times.

Regards

Christof

0 Bayu Eko 5 months ago in reply to Christof Vogt

Prodigy 121 points

Okay thank you very much, we will try it.

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LP-AM243: How to improve Modbus TCP server response time performance?