S7-200 CPU and touchscreen

I am trying to connect siemens S7-200 CPU226 with Eurotherm TS8006 touch panel using PC/PPI cable but they are not communicating.
I have used RS 232 port on the touch panel and selected the S7 via PPI protocol in the touchscreen software.The drop number 2 has been used to identify CPU226.I am trying to access the bits of V memory of S7 CPU.The referance tag has been created on the touchsreen software to access the CPU 226.
I am using STEP7 Microwin 3.1 to program CPU226.I need to know why they are not communicating with eachother.Can anyone explain the reasons for this problem who has experience using S7 with a thirdparty touchsreen.

Are you sure of the cable? Here's the 432 pinout for the 226

Pin Number Signal Description
1 No connect
2 24 V Return (RS-485 logic ground)
3 Signal B (RxD/TxD+)
4 RTS (TTL level)
5 No connect
6 No connect
7 24 V Supply
8 Signal A (RxD/TxD--)
9 Protocol select

I don,t have much experience about interfacing but RS232 and PPI interface for S7 200 is different. Some conversion cable or circuit is needed between CPU and touch panel.

Touchpanel

This same problem I has with ESA and Siemens 226. Cabels was wrong.