This is a draft for documenting the BPTX monitoring system

This page serves the purpose of collecting information over time, to build the documentation for the BPTX monitoring system.


The BPTX system, short for Beam Pick-up Timing system for Experiments, is developed to measure timing of the two beams in the LHC by acquiring the analog signal from the corresponding pick-ups (sensors) and process it. The system detects wrong positions of single bunches and a possible drift of the Orbit clock with respect to each beam. Furthermore, it contains a visualization tool, to represent the data in a human readable way, as well as pushing the data for longtime storage.

Production Setup

The oscilloscopes used in the BPTX production setup is two identical Agilent DSO9254A running Windows XP. Both scopes are located underground at CMS P5 USC in a 19" rack labeled TTC S1E01 and can be accessed from both sides. The tables below shows the input and output setup for the two oscilloscopes.

Description (Master) Signal Input / Output
Orbit 1 for synchronization and timing Orbit 1 Input, Channel 1
Orbit 2 for timing measurement Orbit 2 Input, Channel 2
BPTX 1 for timing measurement BPTX 1 Input, Channel 3
BPTX 2 for timing measurement BPTX 2 Input, Channel 4
Synchronization of master and slave trigger Trigger Output, Trigger Out

Description (Slave) Signal Input / Output
Orbit 1 for synchronization and timing measurement Orbit 1 Input, Channel 1
BC Main for timing measurement BC Main Input, Channel 2
BPTX 1 for timing measurement 10MHz Clock Input, 10MHz
BPTX 2 for timing measurement Trigger Input, AUX


The BPTX channels are terminated with 1 MΩ . This is crucial to prevent reflections in the signal and interference with other systems dependent on the signal. Due to the internal 1 MΩ an additional external 50 Ω resistor is added to avoid additional reflections in the transmission lines. All these terminations are done on the Master scope.


Both of the oscilloscopes are connected to the CMS-Cluster machine "srv-s2b16-28-01". This machine is located inside the .cms network and can be accessed via x2go or .cmsusr. from the network. Both scopes are running a VNC server, and can be used for both monitoring as well as control. To access these, use the hostname and the IP adresses listed below.

Unit IP


Monitoring Software

The BPTX monitoring software is developed in C++ and is compiled in CentOS 7. This was then implemented to the CMS XDAQ framework, and is running by the XML-file of the project. This project can be accessed via the SVN repository (SETT IN REPO HER)... The programmed software connects via Ethernet sockets to the two oscilloscopes and starts to configure those. First the setup method will stop and reset both scopes, then the channel configuration will be started. The start configuration of both BPTX scopes can be seen in the table below.

Parameter Value Name in config*
Coupling DC master_ch3_CouplingAndTermination
Termination 1MΩ master_ch3_CouplingAndTermination
Bandwidth Limit off master_ch3_BandwidthLimit
offset 0 V master_ch3_offset
Scale 1 V/div master_ch3_Scale
Skew 0 s master_ch3_skew
Start configuration for the BPTX channels * For BPTX 1 use "ch3" and for BPTX 2 use "ch4" in the config name.

Parameter Value Name in config*
Coupling DC master_ch1_CouplingAndTermination
Termination 50 Ω master_ch1_CouplingAndTermination
Bandwidth Limit off master_ch1_BandwidthLimit
offset 0 V master_ch1_offset
Scale 300 mV/div master_ch1_Scale
Skew Orbit 1 0 s master_ch1_skew
Skew Orbit 2 30 μs master_ch2_skew
Start configuration for Orbit input channels * For Orbit 1 use "ch1" and for Orbit 2 use "ch2"

Parameter Value Name in config*
Coupling DC master_ch2_CouplingAndTermination
Termination 50 Ω master_ch2_CouplingAndTermination
Bandwidth Limit off master_ch2_BandwidthLimit
offset 0 V master_ch2_offset
Scale 200 mV/div master_ch2_Scale
Skew 0 s master_ch2_skew
Start configuration for BC main

Further the Master and Slave is configured with the following settings. Note the 8 times averaging on the master and the zero averaging at the Slave. It's impossible to average due to the fact that BC-main can be generated without phase lock on the signal which is triggered. This ensures reduced noise on the signals which are always phase locked and in case of internal generation of the BC-main, the capability to analysis BC-main independent signals from the software.

Parameter Value Name in config*
Recording length 10E6 sample master_recordingLength
Sample rate 10E10 sample/s master_sampleRate
Average Mode on master_averagingMode
Average count 8 master_avgCount
Acquire mode RTIMe (real time) master_acquireMode
Skriv nå her MASTER

Parameter Value Name in config*
Recording length 10E6 sample slave_recordingLength
Sample rate 10E10 sample/s slave_sampleRate
Average Mode off slave_averagingMode
Average count 1 slave_avgCount
Acquire mode RTIMe (real time) slave_acquireMode
Skriv nå her SLAVE

Web Interface

Write a quick guide and a overview of the web interface and its framework

SVN repository for the website

-- NicholasSkram - 2017-05-10

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PDFpdf Networking_scheme.pdf r1 manage 26.0 K 2017-05-10 - 11:51 UnknownUser Networking model
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