Downloadable code in a distributed process control system

A system for reprogramming a field device in a process control network having a plurality of field devices communicatively linked over a bus, wherein each of the field devices is capable of communicating on the bus using a standard communications protocol during operation of the process control network, the system comprising:

• a first device that generates downloadable process control program instructions and that transmits the downloadable process control program instructions over the bus using the standard communication protocol;
• and
• a second device capable of receiving the downloadable process control program instructions transmitted over the bus, the second device comprising:
• a processor adapted to execute a set of process control program instructions stored in the second device;
• a first memory adapted to store a first set of process control program instructions that may be executed by the processor;
• and
• a second memory adapted to store the downloadable process control program instructions transmitted over the bus;
• wherein the first device transmits the downloadable process control program instructions to the second device and the second device receives the downloadable process control program instructions and stores the downloadable process control program instructions in the second memory during operation of the process control network while the second device is enabled to execute the first set of process control program instructions that will be replaced by the downloadable process control program instructions to perform process control;
• and
• wherein the processor discontinues executing the first set of process control program instructions to perform process control and begins executing the downloadable process control program instructions to perform process control after the downloadable process control program instructions are stored in the second memory.

A reprogrammable field device capable of being used in a process control network having a plurality of devices communicatively coupled to a bus, wherein each of the devices is capable of communicating on the bus using a standard communications protocol, and wherein a host device is capable of generating input signals including downloadable process control program instructions and transmitting the input signals to the reprogrammable field device over the bus during operation of the process control network while the reprogrammable field device is enabled to perform process control, the reprogrammable field device comprising:

• a processor adapted to execute a set of process control program instructions stored in the reprogrammable field device;
• a first memory adapted to store a first set of process control program instructions that may be executed by the processor;
• and
• a second memory adapted to store the downloadable process control program instructions transmitted over the bus;
• wherein the reprogrammable field device receives the downloadable process control program instructions and stores the downloadable process control program instructions in the second memory during operation of the process control network while the reprogrammable device is enabled to execute the first set of process control program instructions that will be replaced by the downloadable process control program instructions to perform process control;
• and
• wherein the processor discontinues executing the first set of process control program instructions to perform process control and begins executing the downloadable process control program instructions to perform process control after the downloadable process control program instructions are stored in the second memory.

A method of reprogramming a field device in a process control network having a plurality of devices which are communicatively linked on a bus to perform process control functions, the method comprising the steps of:

• downloading process control program instructions from a host device to one of the field devices wherein the host device divides the process control program instructions into a plurality of data packets that are downloaded to the one of the field devices over time while the one of the field devices is enabled to perform process control;
• reassembling the downloaded data packets into the process control program instructions in the field device;
• storing the downloaded process control program instructions in the field device;
• and
• causing the field device to execute the downloaded process control program instructions.

A system for reprogramming a field device in a process control network having a plurality of field devices communicatively linked over a bus, wherein each of the field devices is capable of communicating on the bus during operation of the process control network, the system comprising:

• a first device that divides downloadable process control program instructions into a plurality of data packets and that transmits the data packets over the bus;
• and
• a second device capable of receiving the data packets transmitted over the bus and reassembling the data packets into the downloadable process control program instructions, the second device comprising:
• a processor adapted to execute a set of process control program instructions stored in the second device;
• a first memory adapted to store a first set of process control program instructions that may be executed by the processor;
• and
• a second memory adapted to store the downloadable process control program instructions transmitted over the bus;
• wherein the first device transmits the data packets to the second device and the second device receives the data packets, reassembles the data packets into the downloadable process control program instructions, and stores the process control program instructions in the second memory during operation of the process control network while the second device is enabled to perform process control.