An introduction to Allen Bradley's Micro800 range of low-cost PLCs
Allen Bradley Micro800 PLCs are a range of small PLCs that are designed to control simple, standalone machines. These PLCs are at the core of Rockwell Automation’s Connected Components platform.
In this post, I’ll talk you through the main features of Micro800 PLCs and explain the different types of Micro800 PLCs that are available to use in your projects.
Let’s start by talking about the key features of Micro800 PLCs.
Micro800 PLCs can be extended with plug-in modules.
These modules add extra functionality to PLCs by increasing IO counts or by adding functionality not available in the base PLC like communicating on a DeviceNet network.
Plug-in modules let you personalize a PLC and only pay for the functionality that you need in a project.
Micro800 PLCs are designed to be easy to work with.
Every Micro800 PLC has a USB port that can be used to easily connect to the controller and the PLCs are programmed using IEC 61131-3 standard instructions.
Micro800 PLCs have preferred compatibility with other devices in the Connected Components platform.
This makes it easy to integrate Micro800 PLCs into a system that includes HMIs, safety relays, variable frequency drives, and servo drives. All of these devices can be purchased from a single manufacturer and configured in a single software package.
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Now that we understand the key features of Micro800 PLCs, let’s take a closer look at the PLC families within the Micro800 range.
In the next sections, we’ll look at the specific Micro800 PLC families to understand the features and capabilities of each PLC, starting with the Micro810.
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The Micro810 PLC is nano-PLC that can replace smart relay devices. It is equipped with;
The Micro810 PLC can be equipped with an optional LCD screen. This screen has a built-in memory backup capability so it can be used to copy programs to multiple machines.
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The Micro820 PLC is specifically designed for small, standalone machines and remote automation projects.
It features embedded Ethernet and Serial ports for communications as well as a MicroSD card slot for data logging and recipe management. It can function as an RTU also known as a remote terminal unit for remote machines with support for Modbus RTU and TCP.
The Micro820 has embedded support for 4 thermistor temperature inputs. It can also be extended by installing up to two Micro800 plug-in modules.
Finally, the Micro820 can be paired with a 3.5 inch LCD display which connects to the controller via RS232. The LCD display supports 4 or 8 lines of ASCII text and has a keypad with programmable function keys.
The LCD is rated IP65 for mounting through a cabinet door when used as a simple operator interface.The LCD can also serve as a configuration device for the controller and supports DIN rail mounting next to the controller.
The LCD has a system menu available in several languages for directly viewing and editing program variables and the ability to set the controller's Ethernet address.
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Micro850 controllers are designed for larger stand-alone machine control applications that require flexible communications and greater I/O capabilities.
The Ethernet port supports simultaneous use of;
The Micro850 also supports up to 4 Expansion I/O modules which snap firmly on right side of the controller. The expansion I/O modules are equipped with removable terminal blocks for easy installation.
All in, the Micro850 supports up to a total of 132 on-board, plug-in and expansion digital IO.
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The Micro870 is the latest addition to the Micro800 line up.
It features double the program capacity of a Micro850 controller and support for even more IO modules.
Micro870 controllers can be used for demanding standalone machine applications and small process skids.
Now that you know what PLCs make up the Micro800 family, let’s take a quick look at the accessories that can be used to customize them.
The most important accessory for Micro800 PLCs are the plug-in modules which allow you to extend the functionality of a controller without increasing its footprint.
There is a wide range of plug-in modules available to increase the I/O capacity of a controller and to add new functionality like DeviceNet communication and motion control.
This table shows the complete range of Micro800 plug-in modules that are available to use.
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As well as plug-in modules, the Micro850 and Micro870 controllers support Expansion I/O Modules.
These are more advanced, higher-density I/O modules that clip firmly to the side of the controller to add additional I/O capacity to a Micro850 or Micro870 controller.
The table below shows a complete list of Expansion I/O modules that are available for Micro850 and Micro870 controllers.
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The image shows how you can build a Micro800 catalog number using the Bulletin Number, Product Family, I/O Count and Controller Details.
This sheet will help you quickly understand what options are available for the various Micro800 product families.
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And the following tables outline the different options that are available for each Micro800 Product Family.
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As you can see, there are many different Micro800 product families to choose from. This table may help you select the right Micro800 PLC for your project.
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In this post, I have introduced Allen Bradley’s Micro800 range of PLCs. These PLCs are at the heart of Rockwell Automation’s Connected Components platform and provide a range of cost-effective PLCs for micro-control applications like small, standalone machines.
To learn more about Micro800 PLCs and find the latest information on catalog numbers, check out the Micro800™ Programmable Controller Family Selection Guide, publication 2080-SG001.