Accessing E155 Histograms fromMCC

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last updated 13-Feb-1996

This page has been adapted from E154. Details need to be checked out carefully. Please report mistakes to Charlie Young.

Getting Started

Use the NCD terminal on the North side of the Control Room. It is labelled ncd-e155. Select the login node; currently only one is available. Click OK. Log in using your usual Unix account. Then type:
xhost +
xterm &
netscape &
The first command allows other computers, e.g. the ESA computers, to put a display on this terminal. The second command opens up a new X-terminal, and the thrid command launches a Web browser for looking up these pages.

From the new X-terminal window, telnet to node esaw03 and log in using the account beamtest. This is a group account, whose password changes very often. You can find out the password from any E155 person on shift. Send display back to this X-terminal with the command setenv DISPLAY ncd-e155:0.0,

Change directory to spec10. Run PAW, and select the default workstation type with a carriage return. A new window should appear. This is where all your plots will go. When you see the PAW > prompt, type shm to connect to the shared memory section containing all histograms.


There are several ways you can display the histograms:

  • Use standard Paw commands, h/plot ID, where ID is the histogram number. A complete list of IDs with their corresponding titles is obtained initeractively with the h/list command. The list is rather long, and it may be difficult to locate what you want. If you know the approximate ID number, the command hl ID1 ID2 will give you a list in the range [ID1,ID2] A subset containing beam related histograms has been extracted and explanation added.

  • Macros with hopefully suggestive names have been written to put related histograms on the same page. A list of beam macros is being prepared.
  • History Plots

    One of the more interesting "histogram" is ID=9001. But it is not yet available. It is not really a histogram, but a ring buffer containing information from the last 3000 spills that were analyzed. Since the analysis program works on a sampling basis, these 3000 entries represent much more than 3000/120 seconds. To see the variables in this buffer, type nt/print 9001. In this example, there are 53 variables, each identified by a name, eg status, and its minimum and maximum values in those 3000 spills. Beam variables are at the beginning, followed by data from the 2.75-degree, 5.5-degree and 10.5-degree spectrometers in that order. Depending on the configuration of the analysis program, there may be no variables corresponding to aone or more particular spectrometer. A detailed explanation of each variable can be found elsewhere.

    Here are some basic plotting commands. nt/plot 9001.caltor2 makes a histogram of the one variable caltor2, where the histogram range is automatically chosen to include all data points.

    Scatterplots (or correlation plots in SLC-speak) are made by nt/plot 9001.calgdspl%index where the first (seoond) variable goes with the vertical (horizontal) axis.

    Both plot commands take additional optional arguments. For example, the first optional argument is a cut expression, and specifying L as the 5-th argument joins data points with a line. Specifying ! for intervening optional arguments lets them retain their default values, e.g. nt/plot 9001.angle_y%index status=0 ! ! ! L gives the followinig picture, indicating some anomalous behaviour near index = 5100. These unusual excursions do not show up so well without the connecting lines.

    If there are specific plots or macro commands that would be useful to MCC operations, please contact Charlie Young to get them implmeneted.

    There are manuals available for those interested in the details of Paw. Cern has also provided a very useful Paw Web site with answer to many common questions. E155 experimenters can probably provide some assistance as well.