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Appendix F
NT620S/NT620C Internal Processing
The following processing is executed inside the NT620S/620C. Processing is divided into two types: periodic pro-
cessing and incidental processing.
Periodic Processing
The following processing is executed inside the NT620S/620C to enable high-speed control from the PC.
Usually, the only data read from the PC are the elements used for the currently displayed screen. Even if the con-
tents of the PC words allocated to memory tables are changed, these contents are not updated at the PT unless
the memory table is used for the displayed screen. However, the bit memory tables that can be used with Ver.3 and
later versions of the direct connection function can be set to be read continually.
Reading of of the elements that could not be
registered
[NT620S/620C (PT) processing]
[Details of processing]
PT power ON
Initial processing
Hardware check, communication status check, etc.,
executed
Operation start
Initial values written to the memory tables
When the values registered in the NT620S/620C are
used as the initial values in the memory tables, these
values are written into the allocated words of the PC.
Screen switching
Screen element registration
Reading of registered elements
(PT
→
PC)
(PT
→
PC)
(PT
←
PC)
In order to enable fast batch processing, the elements
used in the displayed screen are registered in the PC
in advance. Approximately 120 words can be
registered per screen.
The statuses of the registered elements are read from
the PC and the display is changed.
The status of the elements that were in excess of the
number that can be registered and could therefore not be
registered is read from the PC, and the display is
changed. This processing is continued until the statuses
of all the remaining elements has been read.
If the number of elements that could not be registered is
large, the PT status control area is read after every two
element readings.
(PT
←
PC)
Reading of of the elements that could not be
registered
(PT
←
PC)
Reading of the PT status control area
(PT
←
PC)
Reading of of the elements that could not be
registered
(PT
←
PC)
Reading of of the elements that could not be
registered
(PT
←
PC)
Reading of the PT status control area
(PT
←
PC)
: Processing performed if necessary
Summary of Contents for NT620C
Page 1: ...Cat No V033 E1 5 Programmable Terminals NT620S 620C OPERATION MANUAL...
Page 2: ...NT620S 620C Programmable Terminals Operation Manual Revised April 2001...
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Page 5: ...vi...
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