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Message ID: 13023     Entry time: Wed May 31 14:23:42 2017
Author: jigyasa 
Type: Update 
Category: Computer Scripts / Programs 
Subject: Establishing the EPICs channels for the GigE 

To set up the EPICs channels for the GigE, Gautam and I followed the steps in the elog by him  8957 .

We copied the 11 required channels from scripts/GigE/SnapPy/example_camera.db to c1cam.db that we created, however due to conflicts with the existing CAM-AS_PORT channels, the channels could not be accessed.

We later changed the database file to Video.db and on restarting the slow machine, it was verified that the channels indeed could be written to and read from.

11 channels were added

C1: CAM-MC1_X (X centroid position)
C1: CAM-MC1_Y (Y centroid position)
C1: CAM-MC1_WX (Gaussian width in the X direction)
C1: CAM-MC1_WY (Gaussian width in the Y direction)
C1: CAM-MC1_XY (Gaussian width along XY line)
C1: CAM-MC1_SUM (Pixel sum)
C1: CAM-MC1_EXP (Exposure time in microseconds)
C1: CAM-MC1_SNAP (Control signal for taking snapshots)
C1: CAM-MC1_FILE(File name for image to saved to - time stamp automatically appended)
C1: CAM-MC1_RELOAD (Reloads configuration file)
C1: CAM-MC1_AUTO (1 means autoexposure on, 0 means autoexposure off)

The procedure followed –

  • Add the channel names to the file C0EDCU.ini (path = /opt/rtcds/caltech/c1/chans/daq/C0EDCU.ini).
  • Make a database (.db) file so that these channels are actually recorded (path = /cvs/cds/caltech/target/c1aux/Video.db).
  • Restarted the slow machine. FB
  • Verify that the channels indeed exist and can be read and written to using ezcaread and ezcawrite.

GV: Initially, I made a new directory called c1cam in /cvs/cds/caltech/target/ and made a .db file in there. However, the channels were not accessible after re-starting FB (attempting to read these channels threw up the "Channel does not exist" error). On digging a little further, I saw that there were already some "C1:CAM-AS_PORT" channels in C0EDCU.ini. The corresponding database records were defined inside /cvs/cds/caltech/target/c1aux/Video.db. So I just added the new records there. I also had to uncomment out the dummy channel in C0EDCU.ini to keep an even number of channels. Restarting FB still did not allow read/write access to the channels. Looking through the files in /cvs/cds/caltech/target/c1aux, I suspected that the epics database records are loaded when the machine is first booted up - so on a hunch I re-started c1aux by keying the crate, and this did the trick. The channels can now be read / written to (tested using Python cdsutils).

ELOG V3.1.3-