Such a ladder was used in RS instruction, but tests found that program implementation, the testing of serial port can send out data by the PLC, but by serial debugging assistant, when sent to the PLC, but can not receive data. Do not know if you are not faced with this problem, I use Delta plc is the ES series. Figure:

RS instruction usage, work I do not understand that very well, what does work?

For example: RS 𐨄 K3 D200 K8 This instruction is not the content of the D100-D102 sent at the same time also the outside world to send messages to the plc, and the D200 is acceptable to send out information? Or move the contents of D200 to D100 then?