National Instruments FP-3000 - Manual (Page 55)

Chapter 4 Block Reference
© National Instruments Corporation 4-3 FieldPoint FP-3000 User Manual
Resource Block
The resource block, defined by the F O U N D A T IO N Fieldbus specification,
contains general information about the device. It also contains parameters
to control the device as a whole, such as restarting the device or taking the
device off-line. The resource block in the FP-3000 contains some
enhancements to the standard resource block definition. For example, it
includes a software version parameter that lists the version information for
the FP-3000 firmware and the version of the F
O U N D A TIO N
Fieldbus
specifications supported.
Types of Function Blocks
The following types of blocks are supported by the FP-3000.
AI (Analog Input)
The AI block reads data from a single analog input channel. This block
performs simple filtering and scaling of the raw data to engineering units
from the input channel and supports limit alarming.
AO (Analog Output)
The AO block writes data to an analog output channel. This block supports
cascade initialization to allow upstream control blocks to switch smoothly
from manual to automatic mode. It also has a faultstate behavior that allows
the block to react if communications fail between itself and the upstream
block.
PID (Proportional–Integral–Derivative)
The PID block implements a PID control algorithm. When at least one PID
block is present in the device, the Process LED reflects the state of the
PID(s) present. In Fieldbus, a PID block must be connected to an upstream
block (such as an AI block) and a downstream block (such as an AO block)
before it can be used for control. These software connections are
established by using host Fieldbus configuration software, such as the
NI-FBUS Configurator.
DI (Discrete Input)
The DI block reads data from discrete input channels. This block performs
simple filtering and processing of the raw data from the input channel and
supports limit alarming.