Today I have faced one problem regarding communication between S7 200 CPU 226 and HMI.

Actually The PLC is Connected with one HMI and two wincc flexible runtime(PC Display), It needs to Show some data in both the Displays at a time. The PLC is having cp243-1. The Ethernet is Connected to Ethernet switch, then to the two Wincc flexible runtimes. HMI is Connected to PLC through Serial Communication. The Actual Problem is at a time, the plc is getting connected to anyone of the runtime. The otherone is not getting connected.

i think you need to configure a second connection, just have a look here:

What should you watch out for when setting up a connection between S7-200 and SIMATIC Panels or WinCC flexible PC Runtime and what are the options?