Applies To:
  • CitectSCADA 5.xx, 6.xx
  • CitectHMI 5.xx, 6.xx

I have several I/O Servers on a local LAN running NetBIOS, and I want to setup a Proxy I/O Server to make the communications more efficient, and also because the remote Clients need to run pure TCP/IP. I don't want to enable TCP/IP on our I/O Servers, because we use DHCP to assign IP Addresses. I am having problems setting up the Proxy I/O Server. What are the exact settings I require to get this working? 

The Network Architecture used in this example is as follows:



The Proxy will use NetBIOS for communications to the I/O Servers, but will communicate to the remote Clients using pure TCP/IP.

Assumed settings:

I/O A Prim has I/O Server name IOAP, Server Name PC1.

I/O A Stby has I/O Server name IOAS, Server Name PC2.

I/O B Prim has I/O Server name IOBP, Server Name PC3.

I/O B Stby has I/O Server name IOAS, Server Name PC4.

PROXY has I/O Server name TCP_PROXY, Server Name PCX.

Step 1:

The first step is to restore the "global" project on the Proxy I/O Server. Then add an I/O Server entry in the Project Editor under the communications form.

In this case, it was called "TCP_PROXY". Note the existing I/O Servers do not need to know about the new I/O Server "TCP_PROXY". This will help, since you won't need to modify/shutdown the existing system. You should run this modified project (with the added TCP_PROXY I/O Server) on all remote Clients PC's.

Step 2:

There are no changes to be made to the Citect.ini of the existing I/O Servers, but it is assumed they have

 TCPIP=0 (default).

Step 3:

Add the following entries to the Citect.ini file on the Proxy Server:


Or to make it more clear:


Then enable TCP/IP and Netbios:




And finally the DNS entry for the PROXY I/O Server, Alarm Server, Report Server, and Trend Server,

Primary= (IP Address of Proxy I/O Server)



Step 4:

Add the following entries to the Citect.ini file on the pure TCP/IP Client:

ALL=TCP_PROXY (or individual I/O Server components as above)
[CLIENT] Primary=PCX
[DNS] (IP Address of Proxy I/O Server)

Note: You will not be able to get Alarm, Report or Trend data directly from the existing I/O Servers. If you do want Alarm, Report or Trend data, you will need to enable the Alarm, Report and Trend Server components to run on the Proxy I/O Server only.