FOUNDATION Fieldbus has defined a standard user application based on blocks. Blocks are representations of different types of application functions. The blocks in a user application are: resource blocks, function blocks, and transducer blocks. The arrangement and interconnections of the blocks determine the function of the fieldbus devices.
Resource block
The resource block describes the characteristics of the fieldbus device such as device name and type, manufacturer, serial number, amount of free memory, and free time. There is only one resource block in a device. You can access the resource block in the DeltaV Explorer to perform the following:
examine the status of the fieldbus device
view and change resource configuration
initiate a master reset or self-test of the fieldbus device
Function blocks
Function blocks provide the control system behavior. The input and output parameters of the function blocks can be linked over the fieldbus segment. For example, a simple temperature transmitter contains an AI function block; a control valve might contain a PID function block as well as the AO block. As with other function blocks, you configure these function blocks in Control Studio and then assign them to run in the fieldbus devices. During a download, the function block tag that is configured in the DeltaV Explorer is downloaded to the device and the function block tag in the device is overwritten.
Transducer block
The transducer block performs front end processing of data signals received from the I/O and offloads this work from the function block. For example, a transducer block might read a signal from a sensor and convert the signal to Engineering Units, thus relieving the function block of the conversion task. The transducer block contains information, such as calibration date and sensor type. There is usually one transducer block for each AI and AO function block.
You can access the transducer block in the DeltaV Explorer to do the following: