Ethernet based instrument-device-servers & IoT to replace PLC, CAMAC, VME based Cryogenic CDAQ systems

Ethernet is one of the most widely accepted communication interfaces today. The power of Ethernet is being realized by the automation Community in the recent past for control & data acquisition applications due to the advancement in technologies like the Internet of Things (IoT) where the Ethernet is the backbone. Traditionally, Automation engineers bought commercially off-the-shelf meters that came with processed analog outputs and then they used these voltage/current outputs to transport each signal to a series of central crate-based digital hardware like CAMAC or VME or PLC for control & data acquisition. A new crate-less model of large number of inter-connected distributed hardware device-servers, each of which has been programmed with embedded control functions, where analog back-end and digital front-end electronics are built together, is designed and developed to replace conventional control & data acquisition systems. The embedded i/o server implemented using ARM processor tcp/ip stack ensure global interconnections. Many of such devices, with very low- bandwidth requirement per node, are connected together to create a low collision network of WEB-compatible instruments compatible to the future IoT applications where signals need slow update- rate. However, the suggested model is also suitable to be used with fast sensors, where each sensor is interfaced directly via UART, SPI, CAN etc. and then only the final processed results are simply transmitted through RPC variables over slow HTTP connections to servers & clients. In this paper, we report successfully built web-compatible instruments using web-based tools which are made fault-tolerant to replace existed Crate- based systems at IUAC Cryogenics automation activities for accelerators. The design is based on ARM® mbed™ IoT Device Platform which provides the operating system, cloud services, tools and developer ecosystem.