Rockwell Automation 1760 Pico GFX-70 Controllers Quick Start User Manual

Page 35

Publication 1760-QS002A-EN-P - April 2004

Lesson 4 6-3

Program, Circuit Diagram,
and Function Block
Diagram

Let us switch to Circuit Diagram View and look at the operands
provided in the Toolbox. As you can see, there are a number of new
operands available for programming Pico GFX-70 devices.

As with Pico projects, the circuit diagram contains contacts and coils
that are linked together via connection lines. These contacts and coils
can, for example, be the inputs and outputs of the controller.
However, function blocks are also provided with contacts and coils
that you can use in the circuit diagram to evaluate the function block
concerned, or control it in some way.

To illustrate the interaction between the function blocks and the
circuit diagram, let us write a small and simple practice program.

The aim of the program is to count the number of actuations on the
P1 button of the device using the counter function block (C..), and to
display the counter status in binary format on the outputs Q1-Q4.

We will use the values in the following table:

If the P button is pressed for the 15th time, the counter (C..) and the
outputs should be reset to zero the next time that P1 is pressed.

To implement this task we first need the input signal of the P1 button.
This is passed to the counter C1 which saves each actuation signal
from P1.

Counter status