Motorola GT10 - Manual (Page 60)

GT10/GT30 3.4 Setting the Basic Communication Area, GT30 and PLC
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3.4 Setting the Basic Communication Area, GT30 and PLC
3.4.1 What is the Basic Communication Area?
Communication between the GT30 and PLC is carried out as shown below.
GT30
PLC
Internal PLC devices
Part reference / output device
For part functions
(free device specification)
Basic communication area
For screen switching settings and system
control
(word device / bit device: 3 words each)
Ongoing
Communication
As shown in the illustration, communication is carried out on an ongoing basis between
the GT30 and internal devices in the PLC. Internal PLC devices are divided into the
following two devices:
Basic communication area
This area is for system control, such as screen switching settings. PLC devices belong
to this area on a fixed basis, and communication is constantly being carried out.
Breakdown of the basic communication area
Word devices (DT, FL, etc.)
3 consecutive words
Bit devices (WR, etc.)
3 consecutive words
– Word devices ––– For reading devices handled in word units (3 consecutive words)
– Bit devices ––– For reading devices handled in bit units (3 consecutive words)
References and output devices for parts
These are devices that are used in parts functions, and can be freely specified by the
user. Communication is carried out on an ongoing basis only for those that are currently
displayed on the screen and pertain to devices currently in use.
With the GT30, before GTWIN screen creation tool is used to specify the devices for
parts functions, the “basic communication area” must be determined.
DT0 to DT2 and WR0 to WR2 are set as the default values for the basic communication
area, but the initial address can be changed using the following procedure.
CAUTION
The basic communication area should be used in the PLC ladder
program to control the GT main unit.
Settings in GTWIN
Select “Configuration” under “File” on the menu bar, and then select the sub–menu
called “GT Configuration”. This displays the dialog box for the GT30 Basic Setup, as