125
Reference Manual
00809-0100-4530, Rev DD
May 2016
5.9.2
F
OUNDATION
Fieldbus block operation
Function blocks
within the fieldbus device perform the various functions required for
process control. Function blocks perform process control functions, such as Analog Input
(AI) functions, as well as Proportional-Integral Derivative (PID) functions. The standard
function blocks provide a common structure for defining function block inputs, outputs,
control parameters, events, alarms, and modes, and combining them into a process that
can be implemented within a single device or over the fieldbus network. This simplifies the
identification of characteristics that are common to function blocks.
In addition to function blocks, fieldbus devices contain two other block types to support the
function blocks. These are the
resource block
and the
transducer block
.
Resource blocks contain the hardware specific characteristics associated with a device; they
have no input or output parameters. The algorithm within a resource block monitors and
controls the general operation of the physical device hardware. There is only one resource
block defined for a device.
Transducer blocks connect function blocks to local input/output functions. They read
sensor hardware and write to effector (actuator) hardware.
Level transducer block
The level transducer block contains transmitter information including diagnostics and the
ability to configure, set to factory defaults and restarting the transmitter.
Register transducer block
The register transducer block allows a service engineer to access all database registers in
the device.
Advanced configuration transducer block
The advanced configuration transducer block contains functions such as amplitude
threshold settings for filtering of disturbing echoes and noise, simulation of measurement
values, and strapping table for volume measurements.
Resource block
The resource block contains diagnostic, hardware, electronics, and mode handling
information. There are no linkable inputs or outputs to the resource block.