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GFK-0825F Chapter 4 Operation 4-3
4
I/O Data for Conventional Modules
Conventional I/O modules provide or receive just one type of I/O data (sometimes referred to as
reference data
). Normally, this data is assigned to the data types shown below; however, any
module's data can be assigned to any data type in BIU memory.
Type of Module Type of Data
discrete inputs I
analog inputs AI
discrete outputs Q
analog outputs AQ
The BIU reads inputs from all conventional input modules and sends outputs to all conventional
output modules during every “sweep" of operations.
Field Control Station
Bus Interface Unit
Conventional
Discrete Input
Modules
Conventional
Discrete Output
Modules
Conventional
Analog Input
Modules
Conventional
Analog Output
Modules
I
AI
Q
AQ
Reference Data
Is Transferred
Each BIU Sweep
I/O Data, Status Data, and Control Data for Intelligent Modules
“Intelligent" modules such as the Micro Field Processor, Thermocouple, RTD, and other intelligent
modules provide and receive multiple types of I/O data. (This data is sometimes called
reference
parameters
). For example, the 16 Point Grouped Analog Input Module provides and receives the
following types of data:
16 (two-byte) analog inputs for channel input data. This data is normally configured to use AI
memory, although that is not required.
88 bits of discrete inputs (I) for module and channel status data.
16 bits of discrete outputs (Q) for fault-clearing commands to the module.
Some intelligent modules use all four available data types: discrete inputs and outputs and analog
inputs and outputs.
The BIU reads input and status data and sends output and command data to intelligent module
during every "sweep" of BIU operations.
Field Control Station
Bus Interface Unit
intelligent
Analog Input
Module
Reference Parameters are
Transferred Each BIU Sweep
I
AI
Q
AQ