How to Read a Datasheet

Learn about what a datasheet is and a few different use cases that a PLC programmer would use on a day-to-day basis.
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In this article, I will explain what a datasheet is. I will also give a few different use cases that a PLC programmer would use on a day-to-day basis.

Datasheets can have many types and names, such as manual, user manual, datasheet, specifications, info card, and product overview.

The principle I will teach you about is that no matter what the sheet is called, you should be able to better understand what the sheet is communicating.

A datasheet is a guide to help a reader understand the capabilities of a device. Datasheets are similar to the torque spec for a vehicle; they are important to follow, because if the datasheets are ignored, you may not be able to accomplish your goals.

Most of the time the data in a datasheet will be in some sort of table format.

Datasheet sections

1. Definitions

Some datasheets will define what a particular letter or symbol will represent throughout the datasheet. These symbols will be defined in the first couple of pages. It is important to make note of what these symbols are.

Datasheet sections - Definitions

I suggest that you highlight the unfamiliar nomenclature either on a printed piece of paper or using a PDF editor, if available.

It might be advantageous to print out the definitions page and have it next to the current page you are looking at.

2. Warnings and Safety Information

When I first get a datasheet that I’m not familiar with, I try to read the warnings. I know firsthand how hard it is to address the consequences of the warnings later instead of avoiding the problems using the warnings.

Datasheet - Warnings and Safety Information

Reading and following the warnings will usually result in a successful experience with any device than if you did not read them.

Each datasheet will have different kinds of warnings due to the nature of the device.

Some safety warnings might include qualifications, such as being qualified to work on electrical components, or they might include warnings about laser radiation, stored energy, and electronic static discharge (ESD).

Datasheet - different kinds of warnings

Like warnings, it is imperative that you heed safety information and requirements for each device.

3. Device Options

Manufacturers sometimes consolidate many devices into one manual.

Instead of making a literal datasheet for every product configuration, manufacturers will tend to group similar devices into one manual.

Datasheet - Device Options

For example, if I wanted to figure out the part number for a laser sensor that had a sensing range of 25mm to 100mm I would then search throughout the document for the table that would describe that sensing range.

Laser Sensor Datasheet - Device Options

After I found the correct sensing range, I would then add the model number to my bill of materials. Even though there is one datasheet there may be many options and sub-options.

4. Wiring Information

Most devices will have some sort of wiring diagram or instructions about how to wire the devices. This is one of the key pieces of data that is usually needed on a datasheet.

Datasheet - Wiring Information

Types of Datasheets

There are many different types of datasheets. Each type will be a little bit different due to the various applications. I will now explain a few different kinds of datasheets.

Integrated Circuits

Datasheets are very common when working with integrated circuits. However, for this article, we will not be focusing on them.

Integrated Circuits Datasheet
Circuit Breakers

In this section, I will explain a few parts of a circuit breaker datasheet. The first section I will explain is the features section.

The description section gives details about the model of the circuit breaker. The features section explains some reasons why you would want to use this circuit breaker series.

Circuit Breakers Datasheet - description and features section

The table describes what models are covered in this datasheet. The first column describes some of the basic characteristics of the circuit breaker.

Circuit Breakers Datasheet - Characteristics Table

This table describes all the different combinations of the model. This table also gives the part numbers of each of the circuit breakers.

Another item of note is the trip curve of the circuit breaker. These are important for each use case.

Circuit Breakers Datasheet - different combinations of the model

This section describes what accessories or options you can use with the circuit breakers.

Circuit Breakers Datasheet - accessories or options

Power Supply

I will now show an example of a power supply datasheet.

Just like in the circuit breaker example, the power supply example has a description. The datasheet also has a features section that shows the features of this power supply.

Power Supply Datasheet - description and features section

Similar to the circuit breaker example, this power supply has accessories that can be bought for a variety of purposes.

Power Supply Datasheet - accessories

This is an example of technical data of a datasheet for a power supply. This data should help you understand what different input voltages are available for this series of power supplies.

Power Supply Datasheet - technical data - Input data
Power Supply Datasheet - technical data - Output data

This is an example of safety information. As stated earlier it is important to follow the warnings to be safe.

Datasheet - Warnings and Safety Information

Here is an example of wiring information to help you understand what terminal will be used to wire the power supply.

Power Supply Datasheet - wiring information

Inductive Sensor

In this example, the datasheet is called an Info Card. Like the other examples, this one has a description of the part. The manufacturer calls this Intended Use.

Inductive Sensor Datasheet or Info Card

This sensor also has a glossary, which is similar to the definitions section in other devices.

Inductive Sensor Datasheet - glossary

Due to the nature of an inductive sensor, this datasheet has a section about the sensing range.

This will usually be in sensor datasheets.

Inductive Sensor Datasheet - sensing range

This section of the datasheet shows the wiring information for the inductive sensor. This isn’t meant to show pin or wire numbers but is meant to show possibilities with wiring.

Inductive Sensor Datasheet - wiring information

This section will show the pinout and the wiring of an inductive sensor. The manufacturer will not always show both the wire color and the pin number, so it is important to understand both methods for wiring.

Inductive Sensor Datasheet - pinout and the wiring


In this article, we have learned the parts of a datasheet for industrial automation devices. We have also looked at some examples of devices and their respective datasheets.

If you have any questions about datasheets, or about circuit breakers, power supplies, and sensors in general, add them in the comments below and we will get back to you in less than 24 hours.

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