Chapter 31. Providing EPICS channel information to Tcl Servers

controlpush is a program that is part of the EPICS support package. It uses a configuration file to connect to a set of EPICS channels, connects to some TCP/IP server and then sends Tcl commands to that server to maintain a set of Tcl arrays that allow the server process to maintain a copy of the state of those channels, their units and when their values were last updated.

controlpush is descsribed fully in: the controlpush manpage.

The intent is that controlpush be pointed at a TclServer. The TclServer is a wish shell extended with the ability to accept commands from TCP/IP connected clients.

You can use controlpush in conjunction with TclServer and application specific scripts to provide a visual display of control system parameters. epicsdisplay is an example of this technique. Another typical use of controlpush is in conjunction with readout skeletons that support tclserver functionality to provide a set of data in the event stream that logs the control system parameters and their changes throughout the run.

controlpush Maintains information in arrays that are indexed by channel name:


Is the most recently received update for channelName.


Are the engineering units for channelName


Is the timestamp of the alst update received for channelName.