codas object monitoring service

The primary Control and Data Acquisition System (codas) of JET is based on a TCP/IP network of more than 150 computers. The codas computers provide the JET machine control and data acquisition for over 70,000 digital and analog signals. The Object Monitoring Service (OMS) is used by applications for monitoring objects for presentation to the JET machine operators and for the operation of individual software components (such as valve state, access control, mimic definition changes and internal data distribution). Each server typically handles connections from around 60 clients monitoring upwards of 2000 objects. Some servers have over 150 clients and 5000 objects. Acquisition libraries are dynamically linked into a running server as required either to acquire data values for objects or to forward requests to other OMS servers. A mechanism involving dynamic linking allows new libraries to be integrated without stopping or changing running software. OMS provides a very reliable and highly successful ‘data-type independent’ means of monitoring many different objects. It allows applications to take advantage of new data sources, without the need to change existing code.