Hi I am having the same problem, some times data transfer taking too long, but sometimes it is one scan time.

i am using ASCII, Serial interface ET200S.

need some advice

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Split from S_SEND takes too much time.

Communications happen on a different time scale. In other words the PLC doesn't stop the OB1 scan while it is sending ASCII. So you have to wait for it to be done. Which communications subroutines are you using? What I'm talking about will be outlined in the help file for each method.

incidentally, the HMI doesn't happen synchronously with OB1 either. so if you are writing and, the HMI is writing a tag - things can get confusing....

KFoldesi

Communications happen on a different time scale. In other words the PLC doesn't stop the OB1 scan while it is sending ASCII. So you have to wait for it to be done. Which communications subroutines are you using? What I'm talking about will be outlined in the help file for each method.

incidentally, the HMI doesn't happen synchronously with OB1 either. so if you are writing and, the HMI is writing a tag - things can get confusing....

 Hi Thanks,

I am using S_SEND and S_RCV blocks for RS422 Full-duplex. I am using s7 414 CPU, Sending/receiving data through ET200S ASCII to a Barcode scanner.

For example if i am sending data for 10 times, out of 10 times, 9 times data is transferred to scanner in one scan time. but sometimes it is taking 5 or 6 scan times to send the data.  There is no send  error information.

but I really cant able to check the configuration(baud rate, stop, etc) in scanner side. do you think this may be problem. 

i checked cables, grounding everything seems to be ok.

also  i am having another 5 plcs with barcode scanner, i didn't see this problem there.

I already check the cables. seems good. 

we need to send a index to the scanner, so scanner will attach its result to that index and send back to plc.

if  wiring problem, then i should see something in Send status.