How to mask EMC towers off in the EMT

IMPORTANT: if you have not been authorised to change the mask then don't touch. Call an EMT expert instead.

If a hot tower is suspected, check with the EMC shifter. Someone may have disconnected an ethernet cable from an UPC-ROM and not informed the Trigger shifter, for example. You can also look for Faulty EMC Channels and at the EMC Electronics Status.

To convert between EMC and EMT numbering schemes, look at EMC/EMT Map. Be careful of the EMC numbering; it is sometimes 0->N, sometimes 1->N+1.

The EMT configuration is at present performed via flat files located in /nfs/bbr-srv02/dataflow/constants/emt. One of these files, with the filename runXXXX.mask, contains configuration data for the algorithm xilinx telling it whether to mask read or ignore input data from the EMC. If there is a noisy tower in the calorimeter which is causing the EMT to trigger excessively then this tower may be masked off from the trigger.

There are lots of such files in the area, called runXXXX.mask. The one that is read on configuration is actually a link called aaaalink.mask which points to the latest runXXXX.mask file.

How to change the .mask configuration file

1) Copy the file pointed at by aaaalink.mask to a new file called runXXXX.mask, where XXXX will be the run number of the first run with the new configuration.

2) Edit the file runXXXX.mask (see below) to set the new mask

3) Delete the link aaaalink.mask and remake it to point to your new runXXXX.mask file. Do not delete the old runXXXX.mask file.

4) Check that the EMT will configure. The actionof configuring will pick up the new mask- there is no need to reboot the rom or power cycle the crate. Take a test run and run the trigger fast monitoring. Check the histograms to verify that the tower you thought you masked off has disappeared from the theta-phi plot.

5) Make a note in the trigger,emt and central BaBar logbooks of what you have changed, and the number of the first run for which it will take effect (ie the number in the name of the ax file). Post a trigger operations hypernews.

How to set the mask in the .mask file

The file runXXXX.mask should look something like the following:

0 1 1 1 1 1 1 1  0 1 1 1
0 1 1 1 1 1 1 1  0 1 1 1
0 1 1 1 0 1 1 1  0 1 1 1
0 1 1 1 1 1 1 1  0 1 1 1
0 1 1 1 1 1 1 1  0 1 1 1
0 1 1 1 1 1 1 1  0 1 1 1
0 1 1 1 1 1 1 1  0 1 1 1
0 1 1 1 1 1 1 1  0 1 1 1
0 1 1 1 1 1 1 1  0 1 1 1
0 1 1 1 1 1 1 1  0 1 1 1
0 1 1 1 1 1 1 1  0 1 1 1
0 1 1 1 1 1 1 1  0 1 1 1
0 1 1 0 1 1 1 1  0 1 1 1
0 1 1 1 1 1 1 1  0 1 1 1
0 1 1 1 1 1 1 1  0 1 1 1
0 1 1 1 1 1 1 1  0 1 1 1
0 1 1 1 1 1 1 0  0 1 1 1
0 1 1 1 1 1 1 1  0 1 1 1
0 1 1 1 1 1 1 0  0 1 1 1
0 1 1 1 1 1 1 0  0 1 1 1
0 1 1 1 1 1 1 1  0 1 1 1
0 1 1 1 1 1 1 0  0 1 1 1
0 1 1 1 1 1 1 1  0 1 1 1
0 1 1 1 1 1 1 1  0 1 1 1
0 1 1 1 1 1 1 1  0 1 1 1
0 1 1 1 1 1 1 1  0 1 1 1
0 1 1 1 1 1 1 1  0 1 1 1
0 1 1 1 1 1 1 1  0 1 1 1
0 1 1 1 1 0 0 1  0 1 1 1
0 1 1 1 0 1 1 1  0 1 1 1
0 1 1 1 1 0 1 1  0 1 1 1
0 1 1 1 1 1 1 1  0 1 1 1
0 1 1 1 1 1 1 0  0 1 1 1
0 0 1 1 1 1 1 0  0 1 1 1
0 1 1 1 1 1 1 0  0 1 1 1
0 1 1 0 0 1 1 1  0 1 1 1
0 0 1 1 1 1 1 1  0 1 1 1
0 1 1 1 1 1 1 1  0 1 1 1
0 1 0 1 1 1 1 1  0 1 1 1
0 1 1 1 1 1 1 1  0 1 1 1

The interesting numbers are coloured red. Each row of 7 red numbers corresponds to 7 theta towers in one phi strip. The numbering goes as follows

      Theta
7 6 5 4 3 2 1 0                Phi

0 1 1 1 1 1 1 1  0 1 1 1        0
0 1 1 1 1 1 1 1  0 1 1 1        1
0 1 1 1 0 1 1 1  0 1 1 1        2
0 1 1 1 1 1 1 1  0 1 1 1        3
0 1 1 1 1 1 1 1  0 1 1 1        4
0 1 1 1 1 1 1 1  0 1 1 1        5
0 1 1 1 1 1 1 1  0 1 1 1        6
0 1 1 1 1 1 1 1  0 1 1 1        7
.
.
.
0 1 1 1 1 1 1 1  0 1 1 1        39

Theta=0 is the forward endcap.
Theta=5,6 is the rear part of the barrel, used for the Y trigger.
Note that theta=7, the backward endcap, does not exist.

After making a change take a test run if possible to make sure you haven't made a mistake. And always make a careful note of what you have done in the trigger operations hypernews.

Remeber that the new mask will not be picked up unless the EMT is reconfigured. So if you change the mask because a hot tower appears during data-taking, be sure to tell the shiftcrew to reconfigure before starting the next run.

If you are not absolutely certain what you are doing, contact an EMT expert.

Jason McFall, 29 October 1999