Tags/Project: Equipment-wiki
| Metadata Field | Document Information |
|---|---|
| Status | Under Review |
| Created | 2026-09-18 |
| Last Updated | 2026-09-29 |
| Author | Davide Cuneo |
| Rev. # | 1.3 |
| Reviewers | Davide |
Introduction and Context
This document provides an overview of the main software tools and computers used at the Magnet Test Stand control room: the EPICS/Phoebus operator screens used to monitor protection and power systems, the SM18 DAQ system used to record test data, the DMM Freia application used for precision electrical measurements, and the different ways to remotely access the test stand computers. It is meant to give enough context to navigate these systems independently, step by step. The content of this document is a refined direct transposition of the meeting with Kevin Pepitone (14-08-2026) and the examples showed during that walkthrough are used to explain the components described.
Acronyms and Terms
| Term | Meaning |
|---|---|
| EPICS | Experimental Physics and Industrial Control System: the control system framework used to operate and monitor the test stand equipment |
| Phoebus | The graphical client used to display and interact with EPICS-based operator screens (file extension .bob) |
| LPS | Local Protection System: as in magnetlps, the Superconducting Magnet Local Protection System |
| PC | Power Converter. (Note: in this document “PC” always refers to a Power Converter, never to a desktop computer; the latter is always spelled out as “computer”) |
| EE | Energy Extraction: the system that safely dissipates the magnet’s stored energy in the event of a quench |
| FGC | Function Generator/Controller: the CERN-developed control system used to send commands to, and control, the power converters |
| Safety Matrix | The hardwired safety system that provides quench-protection and interlock signals across the facility |
| DAQ | Data Acquisition system: records the electrical signals from the magnet test (voltages, currents, triggers, etc.) |
| DMM | Digital MultiMeter: here embodied by the “DMM Freia” application, used for precision measurements |
| RRR | Residual Resistivity Ratio: a standard measurement used to assess the quality of the superconducting cable |
| HF / LF | High Frequency / Low Frequency acquisition systems of the DAQ |
| SM18 | The name of the CERN superconducting magnet test hall; the “SM18 DAQ-GUI” is the DAQ application originally developed there and reused at FREIA |
| SSH / RD / FTP | Secure Shell (remote terminal access) / Remote Desktop / File Transfer Protocol: the three connection modes used to reach the test stand computers remotely |
| PXIe | PCI eXtensions for Instrumentation, express: the modular hardware standard used by the DAQ chassis and its cards |
EPICS and the Phoebus Operator Screens
The EPICS operator GUIs can be accessed from any computer able to VPN in the local network or from any of the computers in the control room. Once there, in the disk folder you look for Public, then phoebus-freia-office. Once Phoebus has opened, the File Browser can be used to reach the folder opi, and inside it the subfolder bob.
Inside this folder, one entry is called Gersemi, which refers to the cryogenic system used to operate the Gersemi cryostat. From the perspective of a magnet test engineer, the three folders of real interest are magnetlps, magnet-ee and magnet-fgc.
magnetlps – Superconducting Magnet Local Protection System
Under the Interlocks tab of this panel, all the conditions required to obtain clearance (“green light”) to operate the power converters can be seen at a glance. These conditions include: correct powering status of the PCs, correct position of the polarity switches, the quench-protection signals coming from the Safety Matrix, and the status of the energy extraction system. Another important condition is that the DAQ must be armed and ready to record data. Without this, permission to power the magnet will not be granted. The lead temperature must also be within the proper operating range.
For the energy extraction branch specifically, the flow switch indicates whether cooling water is actually flowing through the energy extraction resistors. Interlock keys 1 and 2, which are physically present in the control room, can be checked and switched on or off with a simple analogue switch. If a problem occurs while powering the magnet, the power converters can be shut down directly from this same panel. This is possible because the whole interlock chain is wired in series, meaning that if any single element in the chain fails, the entire chain drops. Any failure on this panel results in a fast power abort of the power converters.
magnet-ee – Superconducting Magnet Energy Extraction
This tab shows the quantities and status related to the energy extraction system. It is intended mainly for monitoring: technicians should limit their interaction with this panel to observation, without making changes here.
magnet-fgc – Superconducting Magnet Function Generator Controller
This tab is particularly important, as it gives a full overview of the power converter status and operation. It is also where commands are sent from the terminal to the FGCs that control the PCs. A reference document the detailed command lines can be found within the wiki; for anyone starting out with this panel and the PCs, Yves Thurel (CERN) is a good point of contact.
Magnet Test Stand station computers
Three computers are available at the Magnet Test Stand station. One of them sits behind the protection system rack and must be started manually from there; the other two are reached through a single shared monitor and a switch used to toggle between them.
DMM Freia – Digital Multimeter Application
One of the computers hosts an application called DMM Freia, which connects to the digital multimeter (DMM). Logging in requires a username (a password may also be required, though this was not confirmed during the walkthrough). Once logged in, an existing configuration file can be loaded for instructory purposes. For example, during the walkthrough, the configuration shown was the one for the “Sushi” magnet.
The signals read by the DMM come from the patch panel, which in turn takes its input either from the PotAim chassis or directly from a DCCT connected to one of its inputs. The DMM Freia application effectively works as a precision multimeter, and is used to perform RRR (Residual Resistivity Ratio) measurements, inductance measurements, dI/dt measurements, and similar tests. Full access to this application is already granted to the team.
The Linux Computer and the SM18 DAQ-GUI
The computer running DMM Freia has its own Windows environment. A second computer, located at the back, runs Linux instead, and is used to operate the DAQ system directly. The login for this Linux account uses the username mtbop (the associated password is intentionally not reproduced in this document; see the note at the top).
Once logged in, opening a terminal and checking the command history shows the command normally used to start the DAQ interface:
MTB_app/DAQ-GEN3.sh &
Running this command opens the SM18 DAQ-GUI. The DAQ system itself is reachable at IP address 192.168.10.92.
The RunStart Panel
Once connected to the DAQ and after pressing On, the interface moves to the RunStart Panel. Here, the first things visible are the HF and LF file paths pointing to the configuration files in use (in the walkthrough, these were the configuration files for the Sushi magnet). These configuration files can be enabled and edited directly from this panel; opening Edit shows detailed information, at the bottom of the screen, about the DAQ channels.
What is being shown there are the three DAQ cards that actually receive the signals from the patch panel. These cards are physically installed in slots 3, 4 and 5 of the DAQ chassis, which can be double-checked by looking directly at the hardware: slot 1 hosts a PXIe-8840 (the embedded controller), slot 2 hosts a PXIe-6365 (an input/output module), and the remaining three slots (3, 4 and 5) are the cards actually used to acquire the signals from the PotAims, the power converters, and so on, exactly as listed in the configuration files. In this same configuration, the signals from the LF chain, the EE system and the PCs are also shown as coming from the Safety Matrix.
Once the configuration file has been reviewed and is considered correct, the HF and LF files can be enabled and the arming of the DAQ can be started from the RunStart Panel. At this point, it should not be expected that everything works cleanly right away: since the cards do not immediately read exactly 0 V, and the trigger from the LF chain arrives almost instantly, an initial (essentially spurious) trigger is normal. Despite this, a data file is still correctly created after this first triggering event, so this behaviour should not be mistaken for a fault.
The RunStart Panel also displays the Bench ID, the Magnet name, and the Operator fields, which should be checked and set correctly before testing.
Remote Access to the Test Stand Computers
The three computers described above can also be reached remotely through an application referred to as MOBA (MobaXterm, an application bundling SSH, Remote Desktop and FTP connections in a single interface). Of the connection modes it offers, SSH, Remote Desktop (RD) and FTP are the ones actually used in practice. Remote Desktop, specifically, is used to reach the computer hosting DMM Freia, and from there it is possible to browse its folders and see what is available. To be connected succesfully it is mandatory to be connected to the local FREIA network either by ethernet or VPN.
Acquired data is stored on the DAQ system itself. To retrieve it, an FTP connection is made to 192.168.10.92, using the appropriate password (not reproduced in this document, and to be obtained through the usual channel). Once connected, the data can be found under /daq/data, where the relevant folder can be selected. Retrieving this data can take a long time, since the files involved tend to be quite large.
The same DAQ application can also be reached from a laptop, in which case an SSH connection over the local network (192.168.10.xx) is required, via an Ethernet cable. The IP address of the computer associated with this application is 192.168.10.93; the control room is a convenient place to do this from. The command used to start the application is the same as before:
./MTB_app/DAQ-GEN3.sh
Quick Reference
| Item | Value |
|---|---|
| DAQ system IP address | 192.168.10.92 |
| Laptop-side DAQ computer IP address | 192.168.10.93 |
| Local network range | 192.168.10.xx |
| Data storage path on the DAQ system | /daq/data |
| DAQ-GUI startup command | MTB_app/DAQ-GEN3.sh |
| Example configuration file referenced | Sushi magnet configuration |
| Phoebus operator screens path | Public → phoebus-freia-office → File Browser → opi → bob |
| Linux account username (back computer) | mtbop (password not published here) |
Feedback
Found an error or something outdated in this note? Please contact Davide Cuneo (davide.cuneo@physics.uu.se).