Could not connect to socket port no 502 of 812MJ module

I am using 812MJ ethernet module for modbus protocol communication , I am able to connect , sent and receive data by using AX1 s/w but only if i am configuring my socket 0 port no to ’ 80 ’ . But i need to assign port no 502 (which is used for modbus communication) to my socket 0 , in this case AX1 could not connect to my port . I am unable to find a solution for this , need your help .


Please check the syn packet from AX1 program to W5100 using Wireshark capture program.

When W5100 is opened the correct port num, W5100 send syn/ack packet and syn packet.
If W5100 send the RST packet, W5100 may be opened with wrong port number.
In the case, please check the port number to write it to the W5100 source port number register correctly or not.


Hi, prashantkumar.

It could be happened because port number register is written by wrong number.

So, please read port number register and let me know it and how to write port number to port number register(address, value and etc.)??

Best regards.