In the context of intelligent instrument network, i.e. intelligent sensors and actuators, 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 exchange). We propose to extend the producer-consumer approach to allow the consumer to define and change constraint parameters: frequency of refreshment and maximum of tolerance. We consider especially interval confidence model of data and refreshment capability. A prototype is presented to illustrate and validate the approach on the OSGI platform