In the disclosure, unnecessary notification is suppressed in notification that indicates abnormality of an analog signal. A signal processing device includes: a signal state determination part, which determines, for an analog input signal, whether an abnormal state lasts longer than a predetermined time; a notification signal generation part, which notifies, based on the determination result, a controller that an abnormal state occurs in the analog input signal.

A method and a system collect via a MES, time-stamps of working-statuses of machines and operators, called also actors, for a calculation of a time-dependant component of OLE and OEE indicators in a manufacturing task. The method includes providing a token for assigning to an actor the responsibility of data provision, and defining two meta-statuses for a machine in a task, called operating and booked meta-status respectively. Each meta-status groups a set of machine statuses. A machine is defined to be in an operating meta-status when the machine is in a status engaged in the task and it is able to know and notify its own status. A machine is defined to be in a booked meta-status when the machine is in a status engaged in the task and it is unable to notify its own status.