SimonA

Thanks Mitsu, That's exactly how we have it set up, but try as we might, we have never had the slightest reply from the PLC. Which is why we think the frame may be wrong. If you have simple example of an ASCII 3E or 1E frame then I can try it right now (I assume there is no setting for the frame type) si.

Many thanks for the reply Crossbow, We have had socket communication working on the built-in port but we want to go MC. I am a little confused that you say the built in Ethernet port does not support MC protocol, Am I misunderstanding you? If you are correct then that may well be our problem! but the manual (SH(NA)080811) seems to say otherwise: On page A-9 it says that it covers the Q03UDE (our PLC) On page 3-1 the diagram and table lists MC Protocol as a supported function of the built-in Ethernet port On page 3-14 there is a section 3.3 MC Protocol Communication - this covers set-up of the MC Protocol on the built-in Ethernet port. I've been using the manual "Q-L_UserManual-MELSEC-CommunicationProtocol-ReferenceManual_SH_080008-Q" which describes the frame structure that is not working for us. (3E ASCII). It describes a frame header (Section 3.1.2) but never defines it's content, which is something that could be a problem? (I'm not refering to subheader). Maybe there is something better on the web site. Si.

Hi, We want to communicate from a PC to the PLC using MC Protocol over TCP/IP with a 3E ASCII Frame, but we are not having much success. We can connect over TCP/IP but cannot get any response from the PLC with the frames we are building based on the manual: Q-L_UserManual-MELSEC-CommunicationProtocol-ReferenceManual_SH_080008-Q.pdf Please, can anyone offer a little advice: Q1 - What are the settings in the PLC for the built-in Ethernet port (We have port 1026 listening using MC protocol) Q2 - An example of any ASCII frame that should get a response from the PLC Many thanks, Simon.