Design and Development of a Diagnostics Client for a Beam Loss ...

Design and Development of a Diagnostics Client for a Beam Loss Measurement System at CERN
4. CLIENT IMPLEMENTATION
In the previous chapter we discussed briefly about the new Beam Loss Monitoring System
for the LHC Injectors and more specifically about the acquisition part of the system, for
which the communication client is designed. In this chapter, we outline the design and
development of the client by first introducing the motivation for building this application.
We then advance with a quick introduction of the FPGA firmware and embedded software.
Afterwards, a full description of the client-server architecture protocol is analyzed. This
section includes the definition of the commands sent by the client, the encapsulation of
the frames sent by the server, the types of data sent by the server and the development
steps of the architecture protocol. Finally, the last subchapter follows a detailed outline of
the user interface and in general of the design and implementation of the client.
4.1 Motivation for this Client Development
The final implementation of the new Beam Loss Monitoring System is shown in Figure 2.
The detectors are connected to the input of the new Beam Loss Acquisition Crate, which
hosts up to 8 acquisition modules. Each module is equipped with two small form-factor
pluggable (SFP) transceivers. The first one is a 1310 nm of type LX used for single mode
fiber communication and the other one a 1000Base-T used for Gigabit Ethernet [21]. In
the final system the optical SFPs will be used to communicate directly with the processing
electronics (VME64x crate). Then, through the VME64x Bus, a module with a FESA server
running on a Linux CPU, will be used to provide data to accompanying clients.The purpose
of this communication is for the clients to deal with different settings and interlocks of the
system. This is the standard way for most of the accelerator systems at CERN.
Figure 7: Test Acquisition System and Accompanying Diagnostics Client
At the time of development of the acquisition electronics, the processing electronics were
not yet available. For that purpose, a test system implementation was introduced. This test
system is based on a client-server model using Gigabit Ethernet readout, instead of fiber
optics in the final system. A Nios II soft-core CPU is implemented inside the reconfigurable
Emmanouil I. Angelogiannopoulos 22