Method and system of obtaining data from field devices

A method comprising:

• obtaining data regarding a field parameter from a field device by a field controller;
• sending the data from the field controller to a data cache only if the data is different by a predetermined amount than previous data sent to the data cache;
• operating a data acquisition system, wherein the data acquisition system polls the data cache at a polling frequency to obtain the data from the data cache;
• reading asset management data of the field device by the field controller;
• and
• sending the asset management data to the data cache only if the data has changed from previous asset management data sent to the data cache;
• sending the data regarding the field parameter and the asset management data to the data cache by way of a first communication channel, wherein the bandwidth of the first communication channel is less than a bandwidth needed for the data acquisition system to poll at the polling frequency.

A data caching device comprising:

• a first communication port configured to implement a first communication protocol;
• a second communication port coupled to the first communication port, the second communication port configured to implement a second communication protocol;
• a third communication port coupled to the first communication port, the third communication port configured to implement a third communication protocol, and wherein the third communication protocol is different than the first communication protocol;
• wherein the data caching device is configured to receive unsolicited data across the second and third communication ports and caches the data, and wherein the data caching device is configured to receive requests for the data across the first communication port and is configured to provide cached data to the first communication port upon substantially each request received.

A system comprising:

• a data acquisition system;
• a data cache coupled to the data acquisition system, wherein the data acquisition system is configured to poll the data cache for data regarding a plurality of field parameters;
• a first communication pathway coupling the data acquisition system and the data cache, the first communication pathway having a bandwidth sufficient to carry the data acquisition system polls for data regarding the plurality of field parameters;
• a field device configured to create a datum;
• a field controller, remotely located from the data acquisition system, coupled to the field device and the data cache, wherein the field controller is configured to obtain the datum from the field device, and the field controller is configured to send the datum to the data cache only if the datum is different than a previous datum sent to the data cache;
• and
• a second communication pathway coupling the field device and the data cache, the second communication having a bandwidth insufficient to carry the data acquisition system polls for data regarding the plurality of field parameters.

A system comprising:

• a plurality of field devices configured to measure field parameters to create measurement data;
• a supervisory control and data acquisition (SCADA) system coupled to the plurality of field devices, wherein the SCADA system is configured to obtain the measurement data using a request and response format requiring above a predetermined bandwidth;
• a data caching system coupled to the SCADA system by way of a first communication channel configured to have a bandwidth at least as great as the predetermined bandwidth, and the data caching system coupled to the plurality of field devices by way of second communication channel configured to have a bandwidth less than the predetermined bandwidth;
• a field controller coupled to the data caching system by way of the second communication channel, and also coupled to the plurality of field devices;
• said field controller is configured to obtain the measurement data from the plurality of field devices, and is configured to pass the measurement data to the data cache only if the measurement data has changed from previous measurement data;
• said the data caching system is configured to cache the measurement data from the plurality of field devices and is configured to provide the measurement data to the SCADA system.

A system comprising:

• a plurality of field devices configured to measure field parameters to create measurement data;
• a data acquisition system, the data acquisition system is configured to obtain the measurement data using a request and response format;
• a first caching system coupled to and proximate to the field devices, the first caching system configured to cache measurement data;
• a second caching system coupled between the first caching system and the data acquisition system, the second caching system at a location remote from at least some of the field devices, and the second caching system is configured to cache measurement data provided by the first caching system only if the measurement data has changed from previous measurement data and further is configured to provide the measurement data to the data acquisition system upon request;
• a first communication channel coupling the data acquisition system and the second data caching system, and wherein the bandwidth of the first communication channel is at least a great as a predetermined bandwidth for obtaining measurement data by the data acquisition system using the request and response format;
• and
• a second communication channel coupling the second caching system to the field devices, and the bandwidth of the second communication channel is less than the predetermined bandwidth.

A field controller comprising:

• a processor;
• a random access memory (RAM) coupled to the processor;
• a first communication port coupled to the processor, the first communication port configured to communicate to field devices using a first communication protocol;
• a second communication port coupled to the processor, the second communication port configured to communicate to a data cache system using a second communication protocol;
• wherein the processor, executing a program, is configured to perform a process control loop and is configured to send commands to field control devices;
• and
• wherein the processor, executing a program, is configured to receive data from the field devices over the first communication port, is configured to cache the data in the RAM, and is configured to send the data unsolicited to the data cache if the data has changed from previous data sent to the data cache.