Patent ID: 8914156

Claim:
A method for controlling valves for flow path control in a machine having a plurality of processes for establishing flow paths by controlling a plurality of valves that, before being claimed by a particular process, are available to, and controllable by, more than one process, said method comprising the steps of a first process claiming or taking control of a group of valves from said plurality of valves and setting a switching state of said group of valves, said switching states creating connections between the valves to establish a flow path for executing the first process before said first process is executed; comparing the connections defining said flow path with a plurality of connections previously identified as non-permitted connections; in a presence of a non-permitted connection, the machine going into a safety state in which the switching states identified as creating a non-permitted connection are prevented; in an absence of non-permitted connections, permitting the switching states to create the flow path and performing the first process, said claimed valves being non-available to other processes while said valves are claimed by said first process and other processes being unable to change the switching state of said claimed valves while said valves are claimed by said first process; polling by a second process of a valve being used in said first process resulting in a request to the first process claiming said non-available valve for a release of said non-available valve, said first process itself making a decision on said request for the release of the non-available valve claimed by said first process; the current and scheduled switching states of the valves being monitored during performance of said plurality of processes by said machine to avoid a flow path having a non-permitted connection.