3.DATA EXCHANGE WITH CPU
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3. DATA EXCHANGE WITH CPU
The F159 exchanges data with CPU using the following devices: High
performance I/O unit relay area (Weight and Status data) and high performance
I/O unit DM area (weighing setting and initial setting data).
Weight data
Analog signal from the load cell is converted into digital Weight data.
Weight data is allocated to one of the relay area of the CPU units’ high
performance I/O unit based upon the unit number. The data is exchanged
regularly every time I/O refresh takes place.
Status data
Status data includes various status and error information.
Status data is allocated to one of the relay areas of the high performance I/O unit
in the CPU unit based on the unit number. The data is exchanged regularly every
time I/O refresh takes place.
Weighing setting data
Settings for performing Weight measurement.
One F159 is allocated, based on its unit number, to a selected DM area for high
performance I/O unit (inside CPU unit). Data is written to the DM area in
synchronization with: power-on, refresh start, and request bit (On-edge). Data is
also read out using the request bit’s On-edge: the bit can be used both for reading
and writing depending on R/W bit status.
Initial setting data
Parameter settings for using F159 as a Weight Module.
A set of initial setting data for each F159 is allocated, based on its unit number,
to a DM area for high performance I/O unit (inside CPU unit), and is written to
this area when the unit is powered on, or a refresh cycle is started.
