In the context of intelligent instrument network, i.e. intelligent sensors and actuators, the user or the designer has to manipulate variable network functions. Service model allows the designer to formalize and manipulate information access. Service model also permits to, check, control and react from instrument data and this approach is web-enable. Producer-Consumer pattern facilitates design and intelligent instrument networking. The connection between producer and consumer can be checked (i.e. type of data) and filtered (condition of sending). We propose to extend the producer-consumer approach using service model for variable subscription service where conditions of subscription constraint could be expressed. We consider interval confidence model of data and several consumers to produce the event or data to be subscribed. A prototype is presented to illustrate and validate the approach on the OSGi platform.