Data Acquisition (DAQ)
 Figure: Readout of the ATLAS End-Cap Alignment System. Five VME crates hold LWDAQ relays and controllers. Hundreds of root cables travel over one hundred meters into the detector cavern, where they read out thousands of devices through multiplexers. |
We perform all our data acquisition over TCPIP. For low-speed acquisition, which we define as 1 MByte/s or slower, we achieve control and readout with our binary Long-Wire Data Acquisition (LWDAQ) protocol. For high-speed acquisition, we achieve control with a text interface and readout with the standard secure file transfer (SFTP). Our LWDAQ hardware provides exactly-timed, synchronous control of a large number of instruments, as well as synchronous, low-speed readout of images and measurements. The largest LWDAQ systems consist of several relays, dozens of controllers, hundreds of root cables, hundreds of repeaters, hundreds of multiplexers, thousands of branch cables, and thousands of devices. The smallest LWDAQ systems consist of a relay, a controller, and a single device built one enclosure. The relay is the component that provides an Ethernet socket and TCPIP messaging. The oldest relays, such the one built into the LWDAQ Driver (A2071E), provided a 10-Base-T interface and required a separate 24-V power adaptor. The newest relays, such as the Telemetry Control Box (TCB), provide a 100-Base-T interface and run on Power-over-Ethernet. Our Raspberry Pi Data Acquisition (RPDAQ) provides control of a small number of instruments, as well as high-speed readout of images and measurements. Our Animal Cage Camera ACC is an example of an RPDAQ device. All RPDAQ devices are Power-over-Ethernet and can support both 1000-Base-T and wireless network connections. The RPDAQ provides high-speed acquisition, on-board data buffering, and real-time compression. Because Raspberry Pi runs a pre-emptively multi-tasking operating system, it do not lend themselves to precisely-timed or synchronous control of sensors and actuators. Control and readout of all our instruments is provided by our open-source data acquisition software. This software is named simply "LWDAQ", and is available in our OSI-INC GitHub repository. Despite being named after the Long-Wire Data Acquisition System, the LWDAQ software provides control and readout for RPDAQ devices. The Videoarchiver Tool controls, configures, and reads out our RPDAQ cameras. It also provides post post-acquisition analysis services. The Neuroplayer Tool provides machine-learning event detection for previously-recorded telemetry signals. |