ISPSoft User Manual

Chapter 11 Structured Text
11.4 Example of a Structured Text
11.4.1 Explanation
The example is about the control of a tower light. A tricolor light and a buzzer are used. The control
mechanisms for various device statuses are listed below. If more than one device status appears,
the device status which is given precedence over the others is displayed.
Light
State
code
Device status
Red
light
Yellow
light
Green
light
Buzzer Precedence
4 The device is malfunctions. ON OFF OFF Flash Highest
3
The device malfunctions.
(The buzzer is turned off.)
Flash OFF OFF OFF
2 The device is operating. OFF OFF ON OFF
1 The work is done. OFF Flash OFF OFF
0 The device is idling. OFF ON OFF OFF Lowest
11.4.2 Planning Hardware
In this example, the AH500 series CPU module AHCPU530-EN, the digital I/O module
AH16AP11R-5A, and the four-slot main backplane AHBP04M1-5A are used. The table below is an
I/O allocation table.
Type ID Description
Digital output Y0.0 Red light
Digital output Y0.1 Yellow light
Digital output Y0.2 Green light
Digital output Y0.3 Buzzer
11.4.3 Planning a Program
(1) If the flag ERROR is ON, and the flag BUZZER_OFF is OFF, the state code will be 4.
(2) If the flag ERROR is ON, and the flag BUZZER_OFF is ON, the state code will be 3.
(3) If the flag ERROR is OFF, and the flag RUNNING is ON, the state code will be 2.
(4) If the flags ERROR and RUNNING are OFF, and the flag COMPLETE is ON, the state code
will be 1.
(5) If the flags ERROR, RUNNING, and COMPLETE are OFF, the state code will be 0.
(6) Every state code corresponds to a light. The control of the tricolor light has many practical
applications, and the tricolor light can be displayed in various ways. Considering that a
program can be expanded and reused, a function block is created.
11.4.4 Creating a Program
Start ISPSoft, and then create a new project.
The hardware configuration in this example is the same as the hardware configuration in chapter 4.
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