EPICS Channel Archiver Data Provider Guide

This page provides documentation for users and programmers of AIDA's EPICS Channel Archiver Data Provider. There are currently two EPICS Channel Archivers (one for LCLS and one for NLCTA) that are running and archiving data. There is also data available for a EPICS Channel Archiver that formerly collected data for the PEPII project. The EPICS Channel Archivers are capable of storing EPICS data at a faster rate than the SLC History buffer system.

Users Guide

This section describes what an AIDA user should know about accessing EPICS Channel Archiver data through AIDA.For general information on using see Basic Users Guide to Aida, and the Aida javadoc, in particular the classes DaObject and DaReference (and DaReference's parent _DaReference) in aida.lib.da which form Aida's programming interface. One can also use Matlab.

Table 1: Summary of AIDA Data Provider for EPICS Channel Archiver Data

SUMMARY
Acquires an array of the values of the named EPICS device, between some given STARTTIME and a given ENDTIME.
Status and limitations	The data provider is complete and there are no known limitations.
Plan	There are currently no plans for enhancements.

EXAMPLES
Schematic	Matlab example using a DaReference and returning a DaValue >> r = DaReference('VPIO:IN20:111:VRAW//HIST.lcls',da); >> r.setParam('STARTTIME','07/31/2008 10:00:00'); >> r.setParam('ENDTIME','07/31/2008 10:10:00'); >> hist = r.getDaValue();
Java	$CD_SOFT/ref/package/aida/test/java/DpChadsTests.java
Matlab	/afs/slac/g/cd/soft/slaconly/ref/package/aida/test/matlab/histDemo.m, this will work for either EPICS Archiver or SLC History data without modification for getting basic values and timestamps and plotting them. Also see this screenshot

INSTANCES
Types	Description
EPICS Device	Syntax	<fields, separated by colons>//HIST.lcls <fields, separated by colons>//HIST.nlcta <fields, separated by colons>//HIST.pepii
	Examples	VPIO:IN20:111:VRAW//HIST.lcls TRS1:KLY:OUT:PAVE//HIST.nlcta HR81:CAV1:VACM//HIST.pepii
Instance Attributes
Attribute		Description
HIST.subsystem		The archived history of the EPICS device (d).
		Methods	Name	Returns
			getDaValue(d)	DaValue containing a rectangular matrix of 5 arrays: [1,:] - the values (double); [2,:] - the times as strings "dd-mmm-yyyy hh:mm:ss" (matlab dateform '0', suitable for datenum); [3,:] repeat count; [4,:] the times as numeric timestamps in UNIX system time format; [5,:] the pulse id; [6,:] the count (1 for a scalar and greater than 1 for a waveform-- count may be used to index into the values array for waveforms to extract the waveform values for each sample, as shown in test 10 of DpChadsTests.java); [7,:] a flag indicating whether the times represent Daylight Savings Time. Extract each array with methods of java.util.Vector such as get() (which DaValue extends).See examples above.
			getAny(d)	A CORBA Any, which should be extracted with edu.stanford.slac.aida.dp.dpSlc. histDataHelper.extract().See example.
		Arguments	Name	Req/ Opt	Syntax	Semantics
			STARTTIME	req	mm/dd/yyyy hh:mm:ss	The time from which you want values of the EPICS device named.
			ENDTIME	req	as STARTTIME	The time up-to which you want values of the EPICS device named.
			DATEFORMAT	opt	DATEFORM0, MMDDYYYY, or MMDDYYYY_FRAC	The format of the data time strings returned. DATEFORM0 is the default format: "dd-mmm-yyyy hh:mm:ss". MMDDYYYY is the format "mm/dd/yyyy hh:mm:ss". MMDDYYYY_FRAC is the format "mm/dd/yyyy hh:mm:ss.hh"

[SLAC ESD Software Engineering Group][ SLAC Home Page]

Author: Bob Hall 17-May-2005
Modified by: Bob Hall 17-Aug-2007, Added description of new pulse id.
Modified by: Bob Hall 10-Sep-2007, Added description of new count field for waveforms.
Modified by: Bob Hall 31-Jul-2008, Added description of new optional INDEX parameter.
Modified by: Bob Hall 02-Aug-2008, Added description of new Daylight Savings Time flag.
Modified by: Bob Hall 13-Jan-2009, Removed description of obsolete INDEX parameter.