Contents
Beginner

PLC Programming Fundamentals - XIC Instruction

By
Vladimir Romanov
|
July 17, 2018
Table of Contents

Introduction

The XIC, also known as Examine If Closed, instruction is one of the fundamental instructions used in ladder logic programming for Programmable Logic Controllers (PLCs). This instruction is always found on the left side of a ladder rung and will verify if the specified bit is in a logic HIGH state. If that’s the case, the instruction will evaluate to true and allow the rest of the rung to execute.

Example & Usage of XIC

Here’s a real-world scenario of an XIC instruction:

  1. A Micrologix 1100 Allen Bradley PLC is used to control a process.
  2. A normally open push button (“System Start”) is connected to Input 0 (I0/0 of the PLC).
  3. An operator presses the button.
  4. The XIC instruction is tied to I0/0.
  5. The XIC instruction evaluates to TRUE while the button is pressed.
  6. The XIC instruction evaluates to FALSE while the button is released.

Programming example in RSLogix 500:

PLC XIC INstruction RSLogix 500

Data Types Allowed for XIC

The XIC instruction will work with the following data types within the RSLogix 500 environment:

  • Boolean – The XIC may only evaluate TRUE/FALSE or 1/0 or HIGH/LOW.

Important Notes

  • Note 1 – The XIC instruction was initially used to evaluate the status of inputs landed on the PLC. However, it may be used on any boolean within the program. In other words, it can examine if any boolean within the program is energized. This makes the XIC instruction powerful and versatile.

Video Tutorial

Got a question or comment?

Related Tutorials

Beginner

How to Build an Allen Bradley PLC Trainer Kit for PLC Training at Home

The best way to learn PLC programming is to get hands-on experience. However, as many are trying to learn how to program these devices before landing a job, it becomes crucial to invest in your own hardware in order to accelerate the learning process. That being said, a PLC programmer will face three challenges when it comes to building an effective PLC trainer.

April 10, 2020
|
By
Vladimir Romanov
Beginner

Photo Eye Sensor | How to Wire a Photoelectric Sensor into a CompactLogix Allen Bradley PLC

Learn how to work with photoelectric sensors, understand the basics, how to wire them, how to tie them into various PLCs and field devices and lastly how to troubleshoot them.

April 24, 2020
|
By
Vladimir Romanov
Beginner

PLC Programming | How to Read Ladder Logic

Learn the basics of Ladder Logic, one of the top 5 most popular types of PLC programming languages used in manufacturing environments.

April 7, 2020
|
By
Vladimir Romanov