I have a plc5 project which has RIO panelview and DH+ Factorylink Scada system. PLC5 always read RIO panleview's setpoint(for example PID's setpoint) by RIO comunication, how can other scada system modify the same setpoint in PLC5? Is this the shortcome of RIO panelview? Thanks.

Let me just start by stating that RIO for HMI's or SCADA's is a pain in the lower rear quadrant (if you know what I mean). Today's SCADA's and HMI's incorporate a kind of bi-directional communication with most comm types. In other words you can change a value at the HMI and it is realized at the PLC level. Also you can change a value in the PLC and it is realized at the HMI level. The communication drivers handle the handshaking and other stuff required to make this happen behind the scenes. RIO is unidirectional. You have to program a Block transfer to write a batch of registers and a separate one to read them. This can be real fun. For example with a setpoint, you have to write to one register in the PLC. If for some reason your program must change this value or in your case another SCADA needs to change this value, then you must use another register as feedback to your HMI. Pretty much doubles your work. Then you must handle at the HMI, SCADA and PLC level the logic necessary to make all that work and play well together. Joy. You are also limited in the amount of information you can pass back and forth with the block transfers. Make sure you plan this part carfully or it will bite you in the long run. I think this answers all your questions. RIO works great for remote I/O though... Kinda what it was designed for I guess.