Other EPICS notes

The machine x1bpc5.nsls.bnl.gov is what boots the VME crate which holds the X-1A beamline motor controllers. The motor parameters are stored in the file

/home/epics.lspc31/expmnt/db/motorX1a.substitutions

If the X1B VME crate is rebooted, it will load parameters from this file (we don't know yet if motor positions are unaffected by a crate reboot). We are trying to keep an up-to-date copy of this file in the directory src/epics on x1a.nsls.bnl.gov by going to that directory and doing

scp epics@x1bpc5:expmnt/db/motorX1a.substitutions .

One option for viewing this file is to copy it to a PC and open it with Excel. In Excel, you need to open this as a fixed delimited file using only commas as delimiters. You can then get a clear view of all the parameters in the file.

The following instructions involve the program running on the machine x1bpc5 that saves motor positions, and restores them on a crate reboot. In the directory /home/epics/expmnt/ioc there is a file st.cmd. In this file there is a line

dbLoadTemplate("./db/motorx1a.substitutions")

which defines where the X1A motor substitution file lives. Further down in the file is the line

reboot_restore("home/epics/expmnt/ioc/save_sets/x1a_pos_saves.cfg:reboot

Finally, the .cgi file is in /home/epics/expmnt/ioc/save_sets, where for X1A we have the files x1a_pos_saves.cfg and x1a_saves.cfg.

This paragraph is possibly out of date:

The program ss_arch is running on the machine x1bpc5. It saves a .cfg file every time you move a motor. On reboot, it does a reboot_restore which will restore all the motor positions unless a motor was moving when the crate was reset. The filename for this .cfg files is

/home/epics/expmnt/ioc/save_sets/x1a_saves.cfg:reboot

On the machine x1bpc5, the file

/home/epics/expmnt/ioc/st.cmd

includes the line

reboot_restore("/home/epics/expmnt/ioc/save_sets/x1a_pos_saves.cfg:reboot")

right after the X1B reboot lines. The file

/home/epics/expmnt/ioc/save_sets/x1a_pos_saves.cgf

includes only VAL for all the motors, and x1a_pos_saves.cfg is included in the ss_arch setup.

Individual parameters for motors are described here. For example, the software limit for maximum motor position in user or engineering units (microns for us) is the field HLM, and one can edit this for motor x1a:m10 by doing this on x1a.nsls.bnl.gov:

epics_test x1a:m10.HLM

This will update that parameter as long as the crate is not rebooted; at the next reboot the value stored in motorX1a.substitutions will be used (I think).

For more information on EPICS, go to the main EPICS web site.