The Slope Box Extension

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Figure 1. SBX contents

The Slope Box Extension (SBX) unit provides power to the detector and helps convert signals received from the detector to be sent to the collector box. It extends directly from the slope box. The SBX contains a power board and "pickoff card" along with an optional Raspberry Pi computer for standalone detecter operation. As a whole, the SBX is there to handle much of the signals and processing between the detectors and the greater data acquisition system. The power board of the SBX provides all necessary power to the detector from a single source (48VDC), and allows a single detector and its SBX to be run entirely from one PoE (power over ethernet) port, enabling a detector to operate by itself. Meanwhile, the pickoff card converts signals from the detector to go to the digitizer. Understanding the SBX on a hardware level can be understood by observing the functions of the pickoff card.

These electronics replace all utility of the previously used "VXI system", while providing additional functionality previously unavailable. The addition of the Slope Box Extension moved all detector analog signal conditioning performed by the pickoff directly to the detector. Signal conversion prior to the existence of the SBX required extensive cabling and signal-carrying to the VXI sub-systems before being digitized. As a result of the changes, there is a significant reduction in cabling, and the elimination of the VXI sub-system that previously fulfilled the function of the SBX, making the detector easier to move in the future. The Slope Box Extension now drives a DVI-I cable containing the analog signals, power, and communication interface to a collector box.

EDM Interface for Slope Box

The Raspberry Pi contains an EDM screen allowing users to read and write process variables (PVs). The Slope Box PVs include detector controls and monitoring (HV, Temps, etc.), and the SBX Pickoff PVs include control for signal processing functions (DC offset, gain range, Preamp Reset Clamping, etc.).

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