Programming Function Blocks and Features

Order of evaluation

1.Parentheses ()

2.NOT

3.AND

4.OR, XOR

Example equation using operators and inputs

(A+B)*C computes the result of (A OR B) AND C.

Table 4-28 (A OR B) AND C

 

A

 

 

B

 

 

C

 

 

Result

 

 

0

 

0

 

0

 

0

 

 

 

 

 

 

 

 

 

 

 

0

 

0

 

1

 

0

 

 

 

 

 

 

 

 

 

 

 

0

 

1

 

0

 

0

 

 

 

 

 

 

 

 

 

 

 

0

 

1

 

1

 

1

 

 

 

 

 

 

 

 

 

 

 

1

 

0

 

0

 

0

 

 

 

 

 

 

 

 

 

 

 

1

 

0

 

1

 

1

 

 

 

 

 

 

 

 

 

 

 

1

 

1

 

0

 

0

 

 

 

 

 

 

 

 

 

 

 

1

 

1

 

1

 

1

 

 

 

 

 

 

 

 

 

 

 

 

 

Example equation using iteration

The equation A+B*O computes the result of:

(Input A OR Input B from current machine cycle) AND (Input A OR Input B from previous machine cycle). Table 4-29 shows some possible results of this equation.

Table 4-29 Results of Logic Equation Using Iteration

 

[Input A (current)

 

 

Input B (current)]

 

 

[Input A (previous)

 

Input B (previous)]

 

 

= Result

 

 

 

OR

 

 

AND

 

 

OR

 

 

 

 

 

 

 

 

1

 

1

 

1

 

1

 

 

1

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

1

 

0

 

1

 

0

 

 

1

 

 

 

0

 

0

 

1

 

0

 

 

0

 

 

 

1

 

0

 

0

 

0

 

 

0

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Inverter

The output CVn OS is the logical inverse of the input parameter.

Table 4-30 describes the Inverter prompts. See Table 4-2 for additional prompts.

Table 4-30 Inverter Prompts

 

Prompt

 

 

Range/Selections

 

 

Definition

 

 

INPUT

 

 

OFF, discrete parameter, 0, 1

 

Input source to be inverted.

 

 

 

 

 

 

 

 

 

 

120

Video Recorder – User Manual

Page 134
Image 134
Honeywell VRX180 user manual Order of evaluation, Example equation using operators and inputs, a or B and C, Inverter