GT10/GT30

7.3 GT30 Bit Device Functions

 

 

7.3GT30 Bit Device Functions

In order for communication to be carried out between the GT30 and PLC, an internal device area like that shown below is provided in the PLC. This basic communication area contains two types of devices: word devices, which are used to handle screen numbers and other data, and bit devices, which are used for bit information. The various bits of the bit devices are turned on and off from the PLC, and can be used to control various GT30 operations.

Bit devices

Word position

F

E

D

C

B

A

9

8

7

6

5

4

3

2

1

0

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

N+0

BZ

Forced–

Backlight

Backlight

Backlight

 

 

 

 

 

 

 

 

 

 

 

 

display flag

Valid flag

Flashing

Color

 

 

 

 

 

 

 

 

 

 

N+1

Usage prohibited

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

N+2

 

 

 

 

 

 

 

 

 

 

 

 

 

BAT

 

Data Input In

 

 

 

 

 

 

 

 

 

 

 

 

 

LOW

BAT

 

 

 

 

 

 

 

 

 

 

 

 

 

Progress flag

 

 

 

 

 

 

 

 

 

 

 

 

 

 

flag

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Explanation of system areas

 

 

 

 

 

 

 

 

 

 

 

 

BZ ––– This turns on the buzzer.

Forced–Display flag ––– At the rise when the bit is turned on, the screen specified by the PLC is forcibly displayed. (This is executed only when at the rise of the bit.) Backlight Valid flag ––– When the bit is turned on, the backlight flashing/backlight color control becomes effective.

Backlight Flashing ––– 0: Lighted (normal), 1: Flashing

Backlight Color ––– 00: Off, 01: Lighted, 10: Lighted, 11: Lighted

BAT ––– This goes on if clock data and Hold PLC Device data held in the SRAM are not being backed up normally. (This bit also goes on if the SRAM is not backed up by the internal secondary battery.)

Data Input In Progress flag ––– This is 1 while data is being input, and 0 when data input has been completed.

BAT LOW flag ––– This bit goes on if the battery capacitance drops too low. The battery should be replaced within one week of the time when this bit goes on.

EXPLANATION

DT0 to DT2 and WR0 to WR2 are set as the default values for the basic communication area.

For information on the contents of all areas of the basic communication area, please see page 30.

Turning the backlight on and off

The A and B bits of the initial bit device word are used to turn the backlight on and off. These bits can be changed to change the backlight illumination status.

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