Accessing E154 Histograms fromMCC

last updated 02-Oct-1995

Getting Started

Many X-terminals in MCC cannot be configured by the user to accept displays from other computers. Make sure you are using one of the others. Three are known to work at this time: mccx2, mccx6 and mccx15 . If you get a message about display refused by server later on, you may want to try another terminal.

From the Session Manager, select Options -> Security..., and authorize all users from Node using Transport tcpip. After clicking on Add, and Apply, it should look like:

Then click OK to get out. To save this for future use, select Options -> Save Session Manager.

Telnet to node esaw02 and log in using the account e154onl. Send display to your workstation, or X-terminal, using the command setenv DISPLAY mccx6:0.0, where mccx6 is your X-terminal. Note the trailing :0.0 that you have to add. Change directory to spect5. 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. 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. Beam variables are at the beginning, followed by data from the 2.75-degree spectrometer and then by data from the 5.5-degree spectrometer. Depending on the configuration of the analysis program, there may be no variables corresponding to a 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.

    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. E154 experimenters can probably provide some assistance as well.