1. Introduction

1.1 EPICS Overview

EPICS is a set of software tools and applications jointly developed by Argonne National Laboratory and Los Alamos National Laboratory for the purpose of controlling Particle Accelerators and Large Experiments. Present and future development is being done cooperatively by Argonne (ANL), Los Alamos National Laboratory (LANL), Lawrence Berkeley Laboratory (LBL), the Jefferson National Laboratory (TJNAF), the Spallation Neutron Source Collaboration,  BESSY (Berliner Elektronenspeicherring-Gesellschaft Fr Synchrotronstrahlung m.b.H.) and DESY (Deutsches Elektronen-Synchrotron).

EPICS provides:

     Interfaces to instrumentation from data acquisition, supervisory control, and steady state control through a table entry database.

     Operator interface to all control system parameters through interactive displays.

     Data logging through a table entry archiving file.

     Alarm management through a table entry alarm file.

     Sequential control through a state definition language with convenient database interface routines.

     Channel access routines for interfacing the control system data to data analysis, third party software packages, adaptive control algorithms and any other functions not provided in the control system.

1.2 Access to Operator Displays on sdsshost

Please explore and send me back your comments and suggestions. I need to find out from all of you what type of displays and what information would be most useful to you.

The data that is available is scanned at 5 Hz rate from the TPM computer and shows information that the MCP writes into shared memory. So any information that is in the shared memory I can have served across the network for you to examine.

1.3 Implementation Note

For example, to find the name of process variable that is connected to a display widget on the edd/dm screens click on that widget using the middle mouse button. The resultant pop-up display shows the name of the control system process variable. This name can then be typed or pasted with the middle mouse button into the StripTool or Tcl/Tk xyplot tools.
 

Figure 1. Example of edd/dm Channel Name Pop-up Display

1.4 User Environment Requirements

The execution path must include:

• /usrdevel/peregrin/epics/extensions/bin/sgi

for the EPICS operator applications or extensions including edd/dm, StripTool, and the EPICS-specific et_wish that combines Tcl, Tk, BLT, Tcl-dp, and channel access client library..

• TCL_LIBRARY = /p/tcl/v7_4d/lib/tcl7.4
• TK_LIBRARY = /p/tk/v4_0d/lib/tk4.0
• DP_LIBRARY = /p/tcldp/v3_2f3/lib/dp

1.5 Locations

1.5.1 EPICS

$EPICS/base contains the core of the EPICS system, including channel access communications, the tools to create and manage the real-time database, and the standard database recordtypes and device drivers used by the collaboration. EPICS at APO is built using the SGI as a host and the MV162 as the target.

$EPICS/extensions contains a small number of the numerous add-ons to EPICS as contributed by the many sites. This includes all of the operator display tools.

1.5.2 TPM application

2. EPICS Operator Tools

• The main screens are implemented using the EPICS edd/dm display builder developed at LANL.
• The XY plots are created using a Tcl/Tk program created at LANL using an EPICS interface developed at ANL.
• The Stripcharts make use of the EPICS StripTool program developed at TJNAF.

Descriptions of the XY plot tool and of the StripTool are given below.

Additional operations and analysis utilities can be constructed using existing channel access client interfaces to IDL, Mathematica, Java, SDDS, and other software systems.

2.1 TPM edd/dm Displays

2.1.1 Main TPM Display

The row of four pull-down menus, from left to right, bring up:

• Tcl/Tk XY Plots
• User configurable XY Plot
• Altitude versus Azimuth
• Rotator versus Azimuth
• Axis Data
• Encoder, Current, and Voltage data on the three axes
• Interlock
• List of active interlocks
• Time Plot
• User configurable stripchart
• Position errors stripchart
• Rotator data stripchart
• Altitude data stripchart
• Azimuth data stripchart

Figure 2. Main TPM edd/dm Display

2.1.2 TPM Axis Data Display

Figure 3. TPM Axis Data edd/dm Display

2.1.3 TPM Interlock Display

The Interlock display is meant to show the axis interlocks that are currently activated. This is implemented using edd/dm's ability to control widget visibility based on the value of a control system process variable.
 

Figure 4. TPM Interlock edd/dm Display

2.1.4 TPM "About" Display

The "About" display's purpose is to provide software version and developer contact information.
 

Figure 5. TPM "About" edd/dm Display

2.2 Tcl/Tk-based XY Plots

This simple utility allows the creation of real-time XY plots of upto three variables against a single variable on the same axis. The variables are EPICS process variables whose names are listed in section 3. of this document.

The values of the named process variables are fetched every 0.5 seconds. Changing the format of the axes (Min, Max, Nint) does not cause data to be lost.

The operator input fields are:

• OPDES - this is the process variable
• Min - Minimum value for the X (or Y axis)
• Max - Maximum value for the X (or Y axis)
• Nint - Number of labeled intervals on the axis. There is a tick mark between every pair of labels.

The operator controls from left to right are:

• Start - Start data acquisition and plotting loop
• Stop - Stop data acquisition and plotting loop
• Clear - Erase graph and stop
• Quit - Exit Program

 

Figure 6. Sample XYPlot Tcl/Tk Display

2.3 StripTool

2.3.1 Program Initialization

The configuration files presently resident in sdsshost:/usrdevel/peregrin/tpm/tpmApp/opi are:

• tpm_alt.cfg  - Altitude axis data
• tpm_az.cfg   - Azimuth axis data
• tpm_err.cfg  - Altitude, Azimuth, and Rotator position errors
• tpm_rot.cfg  - Rotator data
• tpm_ws.cfg - Windscreen LVDT

2.3.2 Example StripTool display

• The names of the EPICS process variables being plotted are shown in the column on the right-hand side. These names are enclosed in boxes that indicate the data color. Other information listed are the units and the display min and max for that channel. Clicking on that box changes the vertical axis on the left-hand side to reflect those limits.
• The buttons along bottom of the display have the following functions (given from left to right): Pan Left, Pan Right, Zoom In, Zoom Out, and Auto Scroll.
• The control menu can be accessed by clicking and holding down the right mouse button on the main part of the display. The options in this menu are:
• Controls Dialog - see below.
• Toggle Scroll Buttons - on and off.
• Print - defaults to the printer hdraper at APO.
• Snapshot - screen capture.
• Dump - to an ASCII file.
• Dismiss - close display.
• Quit - exit program.

2.3.3 StripTool Controls Dialog

• Signal Connect
• Time Controls
• Graph Options
• Curves
• Application Controls

2.3.3.1 Signal Connect

2.3.3.2 Time Controls

2.3.3.3 Graph Options

2.3.3.4 Curves

2.3.3.5 Application Control

• Show stripchart
• Clear the stripchart - removes all process variables
• Dismiss the controls dialog window
• End program
Figure 8. Example StripTool Dialog Window

3. Real-Time EPICS Database

3.1 Database Descriptions

Name - the location of the record in the EPICS global namesake implemented on the local SDSS Internet. This is the string that clients across the network use to access this record. The name is what can be used by any operator tool including the display manager, Strip Tool, and Tcl/Tk applications.

Description - the information contained in the record.

Type - the nature of the database record.

Units - the units that the record value is in.

Scan Rate - the frequency at which the record is updated.

3.2 Shared Memory Access

3.2.1 Data Transfer

3.2.2 Altitude Axis

3.2.3 Azimuth Axis

3.2.4 Instrument Rotator

3.2.5 Windscreen

3.2.6 Interlocks

3.3 Derived Quantities

3.4 Other