How to make WIZ110SR totally transparent to connect PC(serial) to RTU (Serial)

Question

i have two wiz110SR connected as indicated in the diagram Below: when i connect two PCs at the serial ends, the PCs are able to communicate. But when i replace one PC with an RTU, im unable to communicate with the RTU. To troubleshoot the problem, i disconnected the RTU and looped the TX and RX of the serial. i noted the wiz110SR reclaculates the checksum before transmitting to RTU. Is it possible to prevent the wiz110SR from recalculating the checksum? since the RTU rejects the newly calculated checksum? I need the wiz110SR to be totally transparent and allow the serial end-to-end communication to flow. I will appreciate if you can give me any other information needed. configurations for WIZ110SR : Thank you.

jameskim · Answer

Hi, I’m sure your RTU want to get a whole data in one time but it discard the received packet because it was not completed yet. The second picture of screeshoots of WIZ105SR configuration tool shows that you don’t use any [color=#FF0000]Data Packing Condition[/color]. With no Data Packing Condition, all our serial to ethernet modules makes a ethernet packet with data in serial rx buffer regularly and it split a whole data from serial to several ethernet packets. Unfortunately, your RTU expects an ethernet packet to have a complete data and it discard each of packets from WIZ105SR because all doesn’t have a complete data in it. I recommend you use [color=#FF0000]Data Packing Condition[/color] option to get communication succeeded. You can use any of them but “[color=#FF0000]Time[/color]” option is the best in almost most environment. If a serial data chunk from the serial device occurs in a few seconds or a few hundreds milliseconds, put [color=#FF0000]100[/color] in ‘[color=#FF0000]Time[/color]’ field in [color=#FF0000]Data Packing Condition[/color] section. You must get what you want. Thank you. BR, James.