Mitsibushi to Siemens S71500 Communication problem

[Nforbes01]

Hi,

I currently using TCP to communicate a mitsibushi QU03 to S71515-2PN.

I have succesfully set up comms for send and recieve but on the siemens receive side it appears every second byte is being missed, therefore 256 as an integer on the Siemens side appears as 0 instead of 256.

Every first byte of each word is fine, but does not transfer the second byte in the word.

anyone experienced this beofre?

Thanks

Neill

 

[mk42]

Every first byte of each word is fine, but does not transfer the second byte in the word.

I've often seen cases where byte swapping occurred, which could cause something like what you are seeing. If Device A is sending 16 bit integers, it could appear as 256, 0 on one side and 0, 256 on the other side.

I've never seen situations where half the data simply disappeared, though.

 

[Pete.S.]

Every first byte of each word is fine, but does not transfer the second byte in the word.

You have to check what is actually sent.

You need Wireshark and a switch with port mirroring capability.

Send something like 1,2,3,4 so you can see if you are catching the message from the beginning as well.

 

[Nforbes01]

Hey,

Thanks for the reply but I am putting these into integers and doing a byte swap afterwards so have already compensated for that