We describe how the R-GMA (Relational Grid Monitoring Architecture) can be used to allow for instrument monitoring in a Grid environment. The R-GMA has been developed within the European DataGrid Project (EDG) as a Grid Information and Monitoring System. It is based on the Grid Monitoring Architecture (GMA) from the Global Grid Forum (GGF), which is a simple Consumer-Producer model. The special strength of this implementation comes from the power of the relational model. It offers a global view of the information as if each Virtual Organisation had one large relational database. It provides a number of different Producer types with different characteristics; for example some support streaming of information. We describe the R-GMA component that allows for instrument monitoring, the CanonicalProducer. We also describe an example use of this approach in the European CrossGrid project, SANTA-G, a network monitoring tool.