S5 Siemens to HMI

Hi,
I have a Siemens S5 135U with 928B processor. It has 2 serial ports, 1 for programming (used frequently) and another for HMI (current use is for OEM HMI). Problem is I want to add another HMI package to the PLC as the existing OEM one that we have cannot be moified.

Can I 'split' the serial ? Is there a card that can be bought for more serial or Ethernet comms?
New HMI will be RSView via KEPServer

Any help appreciated....

Hello !
If I remember correctly you can buy the second card with two serial inputs, if you have the cpu with changeble second "comm-card"

CP524 has one serial port, CP525 has two.

Kind regards,

You can split the S5 serial by PGMUX
http://www.process-informatik.de/pgmux.htm#mux_sie

Perhaps VIPA has a PGMUX
www.vipa.de