Summary
This page introduces the Schneider Electric Modicon M221 Programmable Logic Controller (PLC) family. It is designed to:
- Provide a brief introduction to the M221
- Introduce M221 accessories
- Frame the M221 family in DigiKey’s portfolio
M221 at a Glance
“Modicon M221” describes a family of Schneider Electric PLCs. Schneider describes the M221 family as “Nano PLC made to control basic automation for machines. Programs with Machine Expert Basic software. Uses TM3 expansion I/O.”
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At the time of this writing, DigiKey offered 28 unique models:
- The lowest cost unit is the TM221C16T featuring 16 points (nine inputs and seven semiconductor outputs).
- One of the largest is the TM221CE40U featuring 40 points (24 inputs and 16 semiconductor outputs).
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Individual family members vary in terms of:
- Output ports with options for both relay and semiconductor
- Power supply with options for 24 VDC or AC units supporting 120 up to 240 VAC
- The number and type of serial and Ethernet ports
- The number allowable expansion modules physically attached to the side of the PLC
There are other differences that can be discovered by reviewing DigiKey’s parametric search engine for the Modicon M221 PLC.
Comparing the M221 to Other Modicon Models
The M221 family is a mid-tier PLC within the extended Schneider lineup.
- For lower cost control consider the Schneider Zelio smart relay. This smaller device includes models with and without an integral display.
- For higher performance application consider the Modicon M241 or the Modicon M251 families.
- For dedicated HVAC consider the Modicon M171 or the more capable Modicon M172
Figure 2: Family hierarchy of Schneider PLCs.
M221 Accessories
The M221 PLC is designed for expansion using a variety of modules that clip to the right side of the PLC.
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The TMH2GDB HMI as shown in Figure 1 is a natural extension for the M221.
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DigiKey has nearly 60 expansion modules including:
- Digital input and output
- Analog input and output
- Temperature (thermocouple)
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A variety of plug-in cartridges are available for the M221. These modules are installed on the face of the PLC. An example is the TMC2AI2 input and the TMC2AQ2C output module. These allow the PCL to interface with 4-20 mA sensors and actuators.
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DigiKey offers safety modules
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DigiKey also offers the TM3XTRA1 transmitter and TM3XREC1 receiver pair. When connected with an RJ45 cable, the modules add simple remote I/O capabilities to the M221 family. This is a unique configuration as the remote I/O uses the same expansion modules as the PLC. For example, a TM3AI2HG module could be attached directly to the M221 PLC while another TM3AI2HG is attached to the TM3XREC1.
Tech Tip: There are thousands of combinations and permutations for the Modicon M221. Recommend you use the Schneider PLC configurator to plan out your M221 configuration. An example configuration is shown in Figure 3 featuring the remote expansion modules.
Figure 3: Screen capture from the Schneider M211 PLC configuration tool showing the RJ45-connected remote modules.
Related Components
The Schneider M221 PLC provides the logic and control of a machine or industrial process. It is never installed in isolation. DigiKey has a growing number of supporting products. This list contains related Schneider Electric products:
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Motor starters and motor starter accessories. A small but important piece is the LUFC00. As shown in Figure 4, the PLC to motor starter wiring effort is reduced to a single RJ45 connection.
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Power supplies such as the 24 VDC ABLM1A24025 or the larger three-phase input ABLU3A24200.
Figure 4: M221 with simplified connection to a motor starter.
Material from DigiKey’s Workbench
These DigiKey-generated TechForum articles authored by DigiKey Application Engineer Aaron Dahlen feature the M221 PLC:
Frequently Asked Questions
How do I program the M221?
The Modicon M221 is programmed using Schneider’s EcoStruxure Machine Expert software.
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Connection is made via a USB cable.
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The PLC is programmed in several different IEC 61131-3 languages including:
- Ladder Diagram (LD)
- Instruction List (IL)
- Grafcet (Sequential Function Chart (SFC))
This article shows an example program featuring a LD User Defined Function Block (UDFB) as shown in this screen capture.
What is meant by Book and Brick Style?
The terms book and brick (standard) describe the M221 PLC’s form factor. The difference is seen in Figure 2:
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Book style describes a PLC that is more upright - like a book. It consumes less DIN rail space when compared to its counterpart. Note that the I/O connections are closely spaced in the lower right-hand side of the PLC.
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Brick (standard) style describes a conventional looking PLC. The PLC is designed with the inputs on the top and outputs on the bottom.
Can the M221 PLC be expanded?
Yes, there are multiple ways to expand the M221 PLC’s functionality including:
- Plug-in cartridge installed on the face of the PLC
- Expansion module that are installed to the right of the PLC
- TM3XTRA1 transmitter and TM3XREC1 receiver remote I/O
- Select models feature an Ethernet port enabling connection to a wide variety of Modbus equipped devices.
Article prepared by the DigiKey technical team to support engineers evaluating the Schneider M221 PLC family.