Safety instrument system and pst initiating method

A safety instrument system comprising:

• a plurality of positioners that controls degrees of opening of a plurality of emergency cutoff valves that are provided in pipes in a plant;
• and
• a higher-level system for controlling PSTs of the emergency cutoff valves, wherein:
• each positioner comprises:
• a querying unit that queries the higher-level system as to whether or not PST initiation is permitted, when a PST initiating instruction has been received from the inputting device in a work area where in the positioner is provided;
• and
• a PST executing unit that executes a PST in the emergency cutoff valve in response to an initiating instruction from the higher-level system and for executing a PST in the emergency cutoff valve through an initiating instruction from an inputting device in response to a PST initiation permitted/prohibited report from the higher-level system, wherein:
• the higher-level system comprises:
• a storage unit that stores a schedule for PSTs, established in advance;
• a PST initiation instructing unit that sends, to the positioner, a PST initiating instruction following the schedule stored in the storage unit;
• a PST execution status acquiring unit that acquires PST execution status information for each positioner;
• and
• a PST initiation prohibition evaluating unit that evaluates whether or not to permit PST initiation based on the execution statuses of the PSTs of each of the positioners when there has been a query from a positioner as to whether or not PST initiation is permitted, reports to the positioner, and evaluates whether or not to permit PST initiation based on the execution statuses of the PSTs of each of the positioners when PST initiation timing has been reached based on the schedule, and, if PST initiation is permitted, instructs the PST initiation instructing unit to send a PST initiating instruction to the positioner.

A safety instrument system comprising:

• a plurality of positioners that controls degrees of opening of a plurality of emergency cutoff valves that are provided in pipes in a plant;
• a plurality of flow rate measuring instruments that measures flow rates of the process fluids that flow through the individual emergency cutoff valves;
• and
• a higher-level system that controls PSTs of the emergency cutoff valves, wherein:
• each positioner comprises:
• a PST executing unit that executes a PST in the emergency cutoff valve in response to an initiating instruction from the higher-level system or an initiating instruction from an inputting device in the workplace wherein the positioner is provided;
• a PST execution status acquiring unit that acquires PST execution status information for another positioner;
• a flow rate measurement value acquiring unit that acquires the flow rate measurement value from the corresponding flow rate measuring instrument;
• and
• a PST initiation prohibition evaluating unit that evaluates whether or not a PST initiation is permitted, based on a PST execution status of another positioner, and on the flow rate of the process fluid flowing through the corresponding emergency cutoff valve, when a PST initiating instruction has been received from the higher-level system or from the inputting device.

A safety instrument system comprising:

• a plurality of positioners that controls degrees of opening of a plurality of emergency cutoff valves that are provided in pipes in a plant;
• a plurality of flow rate measuring instruments that measures flow rates of the process fluids that flow through the individual emergency cutoff valves;
• and
• a higher-level system that controls PSTs of the emergency cutoff valves, wherein:
• each positioner comprises:
• a querying unit that queries the higher-level system as to whether or not PST initiation is permitted, when a PST initiating instruction has been received from the inputting device in the work area where in the positioner is provided;
• and
• a PST executing unit that executes a PST in the emergency cutoff valve in response to an initiating instruction from the higher-level system and for executing a PST in the emergency cutoff valve through an initiating instruction from an inputting device in response to a PST initiation permitted/prohibited report from the higher-level system, wherein:
• the higher-level system comprises:
• a storage unit that stores a schedule for PSTs, established in advance;
• a PST initiation instructing unit that sends, to the positioner, a PST initiating instruction following the schedule stored in the storage unit;
• a PST execution status acquiring unit that acquires PST execution status information for each positioner;
• a flow rate measurement value acquiring unit that acquires flow rate measurement values from each of the flow rate measuring instruments;
• and
• a PST initiation prohibition evaluating unit that evaluates whether or not to permit PST initiation based on the execution statuses of the PSTs of each of the positioners and the flow rate of the process fluid flowing through the emergency cutoff valve corresponding to the positioner that made the query when there has been a query from a positioner as to whether or not PST initiation is permitted, reports to the positioner, and evaluates whether or not to permit PST initiation based on the execution statuses of the PSTs of each of the positioners and the flow rate of the process fluid flowing through the emergency cutoff valve corresponding to the positioner that reached the PST initiation timing when PST initiation timing has been reached based on the schedule, and, if PST initiation is permitted, instructs the PST initiation instructing unit to send a PST initiating instruction to the positioner.

A PST initiating method comprising:

• a querying step for querying the higher-level system that manages PSTs on an emergency cutoff valve as to whether or not PST initiation is permitted, when a positioner that controls degree of opening of the emergency cutoff valve that is provided in a pipe in a plant has received a PST initiating instruction for the emergency cutoff valve from the inputting device in a work area where in the positioner is provided;
• a PST executing step wherein the positioner executes a PST in the emergency cutoff valve in response to an initiating instruction from the higher-level system and for executing a PST in the emergency cutoff valve through an initiating instruction from an inputting device in response to a PST initiation permitted/prohibited report from the higher-level system;
• a first PST initiation prohibition evaluating step for acquiring PST execution status information for other positioners, for evaluating whether or not a PST initiation is permitted, based on the PST execution statuses of the other positioners, and for reporting to the positioner, when there has been a query from the positioner as to whether or not PST initiation is permitted;
• and
• a second PST initiation prohibition evaluating step wherein the higher-level system acquires PST execution status information for each of the positioners, evaluates whether or not PST initiation is permitted, based on the PST execution statuses of the individual positioners, and, if PST initiation is permitted, sends a PST initiating instruction to the positioner, if timing for a PST initiation has been reached based on the schedule.

A PST initiating method comprising:

• a querying step for querying the higher-level system that manages PSTs on the emergency cutoff valve as to whether or not PST initiation is permitted, when the positioner that controls the degree of opening of the emergency cutoff valve that is provided in a pipe in a plant has received a PST initiating instruction for the emergency cutoff valve from the inputting device in the work area where in the positioner is provided;
• a PST executing step wherein the positioner executes a PST in the emergency cutoff valve in response to an initiating instruction from the higher-level system and for executing a PST in the emergency cutoff valve through an initiating instruction from an inputting device in response to a PST initiation permitted/prohibited report from the higher-level system;
• a first PST initiation prohibition evaluating step for acquiring PST execution status information for other positioners and for acquiring a flow rate measurement value from a flow rate measuring instrument for measuring a flow rate of a process fluid through a corresponding emergency cutoff valve, and for evaluating whether or not a PST initiation is permitted, based on the PST execution statuses of the other positioners and on a flow rate of a process fluid through a corresponding emergency cutoff valve, and for reporting to the positioner, when there has been a query from the positioner as to whether or not PST initiation is permitted;
• and
• a second PST initiation prohibition evaluating step for acquiring PST execution status information for other positioners and for acquiring a flow rate measurement value from a flow rate measuring instrument for measuring a flow rate of a process fluid through a corresponding emergency cutoff valve, for evaluating whether or not a PST initiation is permitted, based on the PST execution statuses of the other positioners and on a flow rate of a process fluid through an emergency cutoff valve for which the PST initiation timing has been reached, and for sending, to the positioner, a PST initiating instruction if PST initiation is permitted, when a PST initiation timing has been reached based on a schedule.