Flowserve MX FOUNDATION Fieldbus Field Unit - Manual (Page 38)

MX/QX FOUNdaTION Fieldbus Field Unit FCd LMENIM2330-01 – 08/11
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3.8 Transducer Block
The custom transducer block is the interface between the function blocks and the rest of the MX/QX
FF field unit. It provides all the connections to the actuator itself and contains within its parameters all
the information about the Foundation device, commands, and data feedback. This block is custom-
ized, and the links between the hardware and block are already made to allow the user to access
defined settings for the device.
Many of the links between the Transducer block and the Input/Output blocks are also defined and
may not be altered. Data may be read from the parameters but not all parameters permit write
commands. Writes are limited to the parameters used to set up the actuator control functions.
Some of the Transducer block parameters represent multiple conditions for the state of the actuator.
The tables in Appendix B give a full list of the available parameters.
3.9 Device Description and Capabilities Files
Device Descriptions (DDs) provide an extended description of the data in a device. DDs and
Capabilities Files are obtained from the Fieldbus Foundation: www.fieldbus.org.
The DDs are written in a standard Device Description Language (DDL) to provide an extended
descripton of the field device capabilities and names. A DD can be thought of as a driver for the
device. The Link Active Scheduler (LAS) interprets these DDs to see and use the field devices.
For each device, the device description defines the format of its data:
• Tag name
• Parameter labels
• Parameter relationships
• Coding and how many decimal points to display
• Engineering units
• Calibration and diagnostic menus
• Help text
The host interprets these descriptions and provides views to allow efficient communication of
common group parameters. There is easy access to parameters for:
• Face plate HMI
• Loop tuning
• Configuration changes A Capabilities File describes the communication objects in a fieldbus device.
A configuration device can use Device Description (DD) files and Capabilities files to configure a
fieldbus system without having the fieldbus devices online. The files provide the following:
• Profile information
• Actual number of Function Blocks inside the device
• Function Block timing
• Example communication and function block data
• Host system needs for offline configuration