Yokogawa DO202 2-Wire Dissolved Oxygen Analyzer - Manual (Page 59)

Profibus 4-1
IM 12A00A01-61E
4. PrOFIBUS
4-1. About Profibus
4-1-1 Outline
Profibus is a bi-directional digital communication protocol for field devices, which offers an advancement
implementation technologies for process control systems and is widely employed by numerous field devices.
EXA Series Profibus communication type employs the specification standardized by the Profibus organisa-
tion, and provides interoperability between Yokogawa devices and those produced by other manufacturers.
Profibus comes with software consisting of three AI function blocks, providing the means to implement flex-
ible instrumentation system.
For information on other features, engineering, design, construction work, startup and maintenance of
Profibus, refer to the profibus organisation website: www.profibus.com
4-1-2 Internal Structure of EXA
The EXA contains a structured mapping of function blocks. Each function block serves a specific task.
(1) Physical block
• Manages the status of EXA hardware.
• Automatically informs the host of any detected faults or other problems.
(2) Transducer block
• Converts sensor input to process values which are transfered to AI function block by channels.
(3) AI1, AI2, AI3 function blocks
• Conditions raw data from the Transducer block.
• Outputs conditioned process values
• Carries out scaling, damping and square root extraction.
4-1-3 Logical Structure of Each BLOCK
Sensor
input
Physical block
Block tag
Parameters
Node address
Output
AI function
block
Block tag
OUT
Parameters
AI function
block
Block tag
OUT
Parameters
AI function
block
Block tag
OUT
Parameters Block tag
Parameters
Sensor
Transducer
block
Figure 4.1 Logical Structure of Each Block