My Client

My Client page

As a client, Scream can receive UDP packets, and initiate error recovery if and when necessary. As blocks are received, a summary is displayed in the lower left pane - ‘Block Rx’. Any recovery of lost data will generate diagnostic messages in the lower right pane – ‘Control’.

To receive data from a Scream Server that is pushing data, simply check the ‘Receive Data’ box and ensure the server is pushing to the 'listening' port number at the bottom of the window. No other action is necessary.

To pull data from an enabled Scream Server, use the following procedure:

If not already selected, check the ‘Receive Data’ to enable data reception.
Add the server to the ‘Servers’ list: Right-click anywhere in the ‘Servers’ list box, and select "Add UDP Server...". Enter the IP address and port number that the server is listening on, separated by a colon (:).
Test communications: Right-click on the newly added server, and select ‘GCFPING’ from the pop-up menu. Notice that a message appears in the ‘Control’ window logging the ping being sent. If communcation is good, and the server is enabled for client requests, you will receive a GCFACKN message.
Commence pull: Right-click on the server, and select GCFSEND:L (or GCFSEND:B) from the popup menu to request that the server sends you data (L for little-endian, B for big-endian byte order). You should now see the data appearing in the Main window.
When terminating the link, issue a GCFSTOP command from the popup menu. This is advised, otherwise the server will continue to transmit to a client that is no longer listening. Ensure that the server replies with a GCFACKN message (this will be printed in the ‘Control’ pane). If an acknowledgement is not received, repeat the GCFSTOP command.

The steps above can be repeated as many times as necessary to pull data from multiple servers.

Scream can also communicate directly with TCP-enabled sensors (e.g. using a lantronix serial-to-TCP/IP server box or any other serial->TCP bridge) instead of RS232, or to another Scream server if version 4.3 or above. To set up, use the following procedure:

Add the TCP server to the 'Servers' list: right-click anywhere in the 'Servers' list box, and select "Add TCP Server...". Enter the IP address or hostname and then port number that the server is listening on. (e.g. 192.168.0.10:10001).
Right-click on the newly added entry in the "Servers" list, and select "connect". In the "command" column, scream will report 'connecting'. When a connection has been established, this will say 'connected'.

If using a TCP connection, some devices offer multiple network ports for the data. Each port supports different features, and protocols, so you should ensure you are connecting to a "raw" data port, and not, for example, a telnet-enabled port.