Schneider TM221CE24R — Relay PLC Specs and Buying Guide

By Abdullah Zahid
15 min read
Schneider Electric TM221CE24R Modicon M221 compact relay PLC with Ethernet mounted on DIN rail in industrial control panel

Schneider TM221CE24R Logic Controller: Complete Specifications, Selection Guide, and Alternatives

If you are an automation engineer or procurement specialist evaluating the Schneider TM221CE24R — the Modicon M221 logic controller with 24 I/O, relay outputs, and built-in Ethernet — you are likely in the final stage of a sourcing decision. This controller offers 14 discrete inputs, 10 relay outputs, and 2 analog inputs in a compact 110 x 70 x 70 mm DIN-rail package, powered from a single-phase 100–240V AC supply. The core question to settle before ordering is whether exactly 10 relay outputs and 10 ms output switching meet your load and speed requirements — because those are the fixed boundaries this model operates within.

If you have already confirmed this is the right part, check current pricing and availability for the TM221CE24R at LeadTime.ca — ships worldwide.

Who Should Buy the TM221CE24R — and Who Shouldn't

The TM221CE24R is the right choice for engineers and OEM machine builders who need a compact, relay-output PLC with integrated Ethernet connectivity and a modest fixed I/O count. This model is a strong fit when:

  • Your application requires exactly 10 relay-switched loads or fewer, with no need for transistor outputs
  • You have a maximum of 14 discrete inputs and 2 analog inputs (0–10V range) at the base unit level
  • Your supply source is single-phase 100–240V AC (85–264V operating range); this model is not suitable for DC supply
  • Controlled loads fall within relay output ratings of 5–250V AC or 5–125V DC, with no single relay exceeding 2A
  • Output switching latency of 10 ms and input response times of 5 µs to 100 µs (depending on input terminal) are acceptable for the application
  • Panel space is constrained and DIN-rail mounting on TH35-7.5 or TH35-15 rail is available

If your application requires transistor (solid-state) outputs for PWM control or rapid switching, the TM221CE24R is not the correct model — consider the TM221FE24 instead. For applications needing analog outputs or significantly higher I/O density without expansion modules, the Modicon M241 is the appropriate next step.

On this page:

What the TM221CE24R Actually Does in a Control System

The TM221CE24R is a compact programmable logic controller in the Modicon M221 family from Schneider Electric. Its official product descriptor is: Logic controller, Modicon M221, 24 IO, relay, Ethernet. In practical terms, it functions as the central decision-making processor in a standalone or networked control system — reading sensor states through its 14 discrete inputs and 2 analog inputs, executing the user program, and switching relay contacts to control downstream loads including solenoid valves, motor starters, pump contactors, and indicator circuits.

The 10 relay outputs are normally open contacts. Each relay is rated at 2A continuous, with a maximum of 7A shared across the COM 0 and COM 1 terminal groups and 4A at the COM 2 group. This is not a high-speed switching device — relay contacts carry a mechanical switching delay of 10 ms on both energize and de-energize. The four fast input terminals (I0, I1, I6, I7) achieve 5 µs response, while the remaining standard inputs respond in 35–100 µs depending on terminal assignment. The 2 analog inputs accept 0–10V signals at 10-bit resolution, providing 1024 count resolution across the full scale with a 1 ms conversion time per channel plus one controller cycle time.

Built-in Ethernet connectivity positions this controller for integration into networked facilities without requiring a separate communications module. The unit mounts on standard IEC 60715 TH35-7.5 or TH35-15 DIN rail and draws a maximum of 35 VA at the base unit without expansion modules — rising to a maximum of 58 VA with a full complement of up to 7 expansion I/O modules attached.

Typical System Architecture for the TM221CE24R

The TM221CE24R sits at the field-level control layer — between the engineering workstation or SCADA system above it and the sensors and actuators it directly manages. Here is where it typically sits in the signal and data chain:

  • Engineering workstation or HMI panel communicates with the TM221CE24R via Ethernet for programming, monitoring, and remote diagnostics
  • The TM221CE24R executes the user ladder logic program, reading field device states and computing output commands each scan cycle
  • 14 discrete inputs connect to field sensors: proximity switches, pushbuttons, pressure switches, float switches, and limit switches (24V DC, sink/source capable)
  • 2 analog inputs (0–10V, 10-bit) connect to transmitters such as temperature sensors, pressure transducers, or level sensors outputting a voltage signal
  • 10 relay output contacts switch downstream actuators: solenoid valves, motor starter coils, pump relays, fan contactors, and indicator lamps — up to 2A per contact at 5–250V AC or 5–125V DC

Typical Applications and Deployment Scenarios

The TM221CE24R is a natural fit for small-to-medium discrete and process control tasks where the I/O count matches the base unit capacity. In food and beverage operations, it is commonly deployed as a sequencing controller for filling or capping stations, managing valve actuation and conveyor interlock logic through its relay outputs while reading proximity and photoelectric sensor signals on the discrete inputs.

Water treatment subsystems are a strong use case: pump sequencing, tank level control using the 0–10V analog inputs connected to submersible pressure transmitters, and alarm relay outputs feeding panel indicators or remote telemetry systems. The built-in Ethernet makes integration with SCADA or plant historian straightforward without adding a communications card.

Facility HVAC and utility distribution applications leverage the relay outputs for heating zone valves, fan starter coils, and damper actuators, while the analog inputs monitor temperature or pressure signals. OEM machine builders embedding a cost-effective PLC with a compact footprint and network connectivity — without requiring the higher I/O density of larger platforms — consistently appear in this model's natural application scope.

Application Typical Deployment
Bottling or packaging line Relay outputs control fill valves, reject gates, and conveyor drives; discrete inputs read photoelectric and proximity sensors
Water treatment subsystem Pump sequencing via relay outputs; tank level and pressure monitoring via 0–10V analog inputs
Facility HVAC control Relay outputs switch heating zone valves, fan starters, and dampers; analog inputs monitor temperature signals
OEM embedded machine controller Compact DIN-rail controller managing sensor voting logic, safety interlocks, and relay-switched actuators within a machine enclosure
Process skid batch controller Timed relay switching for mixing, filling, and curing sequences; analog input monitors temperature or pressure transmitter

Key Specifications: What Matters for the Purchase Decision

Parameter Value
Discrete Inputs 14 total — 4 fast inputs (I0, I1, I6, I7) at 5 µs response; 10 standard inputs at 35–100 µs
Discrete Outputs 10 relay contacts, normally open; 2A per relay; 7A per COM 0/COM 1; 4A per COM 2
Analog Inputs 2 channels, 0–10V, 10-bit resolution (0–1023 counts); 1 ms conversion time per channel + 1 controller cycle
Relay Output Voltage Rating 5–250V AC (AC-12) or 5–125V DC (DC-12)
Supply Voltage 100–240V AC rated; 85–264V AC operating range; 50/60 Hz
Relay Output Switching Time 10 ms turn-on / 10 ms turn-off
Relay Mechanical Durability More than 20,000,000 contact cycles (no load)
Relay Electrical Durability 100,000 to 300,000 cycles depending on load type and voltage
Physical Dimensions 110 x 70 x 70 mm; DIN-rail mount IEC 60715 TH35-7.5 or TH35-15
Power Consumption 35 VA base unit; 58 VA maximum with full I/O expansion

Full technical specifications are available on the product page at LeadTime.ca.

TM221CE24R vs. TM221FE24 vs. M241: Which One Do You Actually Need?

Feature TM221CE24R TM221FE24 Modicon M241
Output Type Relay (10 normally open) Transistor (solid-state) Transistor or relay variants available
Output Switching Speed 10 ms mechanical relay Faster solid-state switching Faster solid-state switching
Analog Outputs Not available Not available on base unit Available on select variants
Supply Voltage 100–240V AC 24V DC 24V DC
Base I/O Count 24 (14 in / 10 out) 24 Higher I/O density
I/O Expansion Modules Up to 7 Up to 7 More extensive expansion ecosystem
Ethernet Built-in Built-in Built-in
Best Fit AC-powered panels, relay-switched loads, cost-effective networked control DC-powered systems needing fast switching or PWM Higher I/O density, analog output, motion control

If your application requires transistor outputs for PWM, rapid on/off cycling, or is powered from a 24V DC panel supply, the TM221CE24R is not the correct selection — check current availability for TM221CE24R and compare variants at LeadTime.ca.

Expert Verdict: Is the TM221CE24R Right for Your Application?

The TM221CE24R earns its place as a go-to choice for small-to-medium automation tasks where relay output switching is exactly what the application calls for. Its integrated relay contacts eliminate the need for a separate relay module bank in basic control tasks — a real cost and panel space advantage for OEM machine builders and retrofit integrators working within tight enclosure budgets. With mechanical relay durability exceeding 20,000,000 contact cycles and electrical contact life ranging from 100,000 to 300,000 switching cycles depending on load conditions, this unit is built for the repetitive duty cycles common in packaging, water treatment, and facility HVAC applications. The built-in Ethernet removes the common integration friction of adding a separate communications card, and the 110 x 70 x 70 mm form factor fits the panel spaces where larger PLCs simply don't. For facility managers, OEM builders, and integrators whose applications stay within 14 discrete inputs, 10 relay outputs, and 2 analog inputs, this model delivers a clean, cost-effective solution.

The limits are equally clear. The TM221CE24R has no transistor outputs — any application needing PWM control, high-frequency switching, or solid-state output response must move to the TM221FE24 instead. There are no analog outputs on this model at all; applications requiring analog signal control over a VFD speed reference or proportional valve should step up to the Modicon M241 family. The 10 ms relay switching time and the 10-100 ms range on standard inputs are the hard speed floor — real-time motion coordination or microsecond-level response on most inputs is not achievable here. And it bears stating directly: this model's relay contacts are rated Category AC-12/DC-12 only and are not safety-rated for SIL-required control loops. Safety functions must be handled by dedicated safety relays or a safety-rated controller.

From a procurement standpoint, the TM221CE24R is a well-supported catalog item in the Modicon M221 family from Schneider Electric — a family with broad distributor coverage globally. Sourcing through an authorized industrial distributor rather than a generic electronics channel matters here: authorized channels maintain stock depth for both the base unit and compatible expansion modules, provide technical guidance on integration requirements, and support warranty compliance if issues arise post-installation. View current pricing and availability for the TM221CE24R at LeadTime.ca — the team ships worldwide and can advise on expansion module pairing and lead time before you commit to a build.

For volume pricing or to confirm lead time before committing to a build, contact the LeadTime.ca team directly — we ship worldwide.

What Engineers Need to Know Before Ordering the TM221CE24R

Community discussion on the TM221CE24R is sparse in public forums — searches across r/PLC, r/automation, PLCTalk, PLCS.net, MrPLC, and distributor Q&A sections returned no threads specific to this model or the broader Modicon M221 family. This is not unusual for a well-specified catalog PLC in an application niche where engineers source and deploy the hardware through direct distributor channels rather than crowdsourced troubleshooting. What it does mean is that the authoritative guidance for this part comes from the manufacturer datasheet, authorized distributors with hands-on application experience, and the common-sense engineering checks that prevent the most costly ordering mistakes.

The most consequential mistake engineers make with this model is selecting it expecting transistor outputs. The TM221CE24R uses mechanical relay contacts exclusively — 10 ms switching latency, rated for a maximum of 20 operations per minute at full load under electrical durability testing conditions. For any application where PWM control, soft-start logic, or rapid cycling is required, this model will immediately fall short, and the downstream cost of replacement is significant. The second most common trap is connecting a 4–20 mA current-loop transmitter directly to the analog input. The TM221CE24R analog inputs are voltage inputs (0–10V); connecting a current-loop sensor without an external 510 Ohm precision resistor to convert the signal to a 2–10V range will result in input circuit damage. Distributor technical teams familiar with this model know this immediately — it is the kind of application-specific guidance that does not surface in public forums but prevents real field failures.

When community data is absent and application details matter at the component level, a distributor who actively sells and supports this product family is the right resource to consult before finalizing the order. The LeadTime.ca team handles exactly this kind of pre-order technical verification — confirming I/O count match, relay rating alignment, and expansion module compatibility before the part ships. That conversation costs nothing and can prevent a costly commissioning surprise.

Wiring and Installation Overview

The following points summarize key installation requirements. Engineers requiring full wiring diagrams and step-by-step commissioning procedures should refer to the Schneider Electric TM221CE24R hardware guide available through the official Schneider Electric support portal.

  • DIN-rail mounting requires IEC 60715 TH35-7.5 or TH35-15 rail; the rail must be grounded before the controller is mounted and latched into position
  • Supply connection requires single-phase 100–240V AC at the L and N terminals with protective earth at the ground symbol terminal; the operating range accepts 85–264V AC
  • Discrete input wiring uses 24V DC signals (sink/source capable); fast inputs I0, I1, I6, I7 respond at 5 µs; standard inputs respond at 35–100 µs; software-selectable input filtering of 0, 3, or 12 ms is available per input for noise immunity
  • Relay output wiring requires verification of COM terminal group current limits (7A at COM 0/COM 1; 4A at COM 2) and per-relay current limit of 2A; inductive loads require external surge suppression to protect relay contacts
  • Analog input wiring accepts 0–10V signals only; 4–20 mA sensors require an external 510 Ohm precision resistor (±1% tolerance) to convert current signal to 2–10V before connection to the analog input terminal

I/O Expansion and Scalability

The TM221CE24R supports connection of up to 7 additional I/O expansion modules, allowing the base 24-point I/O configuration to grow as application requirements increase. Expansion modules may be transistor output or relay output types depending on the specific loads being controlled in the expanded system. Engineers should note that adding expansion modules increases total power consumption — the base unit draws 35 VA and the fully expanded configuration can reach 58 VA maximum. COM terminal current sharing between the base unit relay outputs and expansion modules must be factored into load calculations before commissioning to avoid overloading terminal groups.

Wrong-Part Prevention Checklist

Before placing your order for the TM221CE24R, verify each of the following points against your application requirements:

  1. Confirm this model provides exactly 10 relay outputs, not transistor outputs; verify relay load requirements match (2A per relay, 7A per COM terminal)
  2. Verify that 14 discrete inputs + 2 analog inputs (0–10V) match application sensor count
  3. Check that relay output voltage rating (5–250V AC / 5–125V DC) matches all controlled devices
  4. Confirm supply voltage source is 100–240V AC (not single-phase DC)
  5. Confirm DIN-rail mounting (TH35-7.5 or TH35-15) is available and appropriate for panel
  6. Verify Ethernet connectivity requirement; if serial-only or standalone is acceptable, confirm no unnecessary cost
  7. Check that response time tolerances meet application speed requirements (10ms output switching, 5–100µs input detection depending on input type)
  8. Verify no safety-rated switching required; relay contacts are Category AC-12/DC-12, not safety-rated

If any item on this checklist reveals a mismatch, contact the LeadTime.ca team before ordering — we can confirm the correct alternative model and check availability worldwide.

Frequently Asked Questions

Can I expand the TM221CE24R beyond 24 I/O points, and what module types are supported?

Yes. The TM221CE24R supports up to 7 additional expansion I/O modules attached directly to the base unit on the DIN rail. Supported expansion module types include transistor output and relay output modules. Adding expansion modules will increase total system power consumption from the 35 VA base unit draw toward a maximum of 58 VA with all modules installed. If your application requires more than 7 expansion modules or a significantly higher I/O count at the base level, the Modicon M241 family offers a more scalable platform.

Does the TM221CE24R support analog outputs, and can it control a variable frequency drive?

The TM221CE24R has no analog outputs. Its 2 analog channels are inputs only, accepting 0–10V signals at 10-bit resolution. Controlling a VFD via an analog speed reference signal (typically 0–10V or 4–20 mA) requires an analog output — which this model cannot provide from the base unit. For VFD analog control from this controller, an appropriate analog output expansion module would need to be evaluated, or the Modicon M241 with native analog output capability would be a more direct fit.

What is the fastest input response time, and which terminals support it?

The four fast input terminals — I0, I1, I6, and I7 — achieve 5 µs turn-on and 5 µs turn-off response time. The remaining standard inputs respond in 35 µs (I2–I5) to 100 µs turn-on depending on the terminal, with 100 µs turn-off across standard inputs. Input filtering is software-selectable at 0, 3, or 12 ms per input channel and will add to the effective response time if enabled. For applications where most inputs need microsecond-level response across the board, this model's standard input response is a hard limitation.

Are the relay outputs rated for safety control applications?

No. The TM221CE24R relay contacts are rated Category AC-12 (AC loads) and DC-12 (DC loads) under IEC standards. These ratings apply to standard resistive and inductive switching duty and do not constitute safety-rated contacts for SIL-classified control loops or functional safety applications. Safety interlock functions requiring IEC 62061 or ISO 13849 compliance must be implemented using dedicated safety relay modules or a safety-rated controller platform. Do not rely on TM221CE24R relay contacts to fulfill Category 3 or Category 4 safety functions.

Can I connect a 4–20 mA pressure or temperature transmitter directly to the analog input?

Not directly. The TM221CE24R analog inputs are voltage inputs with a 0–10V range and 100 kOhm input impedance. Connecting a 4–20 mA current-loop transmitter without signal conditioning will produce inaccurate readings and risks damaging the analog input circuit if the voltage across the input terminal exceeds rated limits. To use a 4–20 mA transmitter, install an external 510 Ohm precision resistor (±1% tolerance) in the signal path to convert the 4–20 mA current to a 2–10V voltage signal before the analog input terminal.

What happens to the relay contacts at the end of their electrical service life?

Relay electrical durability ranges from 100,000 switching cycles (inductive DC loads at 24V/24W) to 300,000 cycles (resistive AC at 240V/160 VA or light resistive DC loads). As contacts approach end of electrical life, contact resistance increases, leading to voltage drop across the contact and potential unreliable load switching. The mechanical contact life without load exceeds 20,000,000 cycles, meaning electrical wear from load switching will dominate contact replacement intervals long before mechanical fatigue. In high-cycle applications, monitoring load activation reliability and scheduling periodic contact inspection is advisable.

Why Order the TM221CE24R Through LeadTime.ca

  • LeadTime.ca ships worldwide — whether your project is in North America, Europe, Asia, or elsewhere, sourcing the TM221CE24R through an authorized industrial distributor ensures genuine product and warranty coverage
  • Pre-order technical support is available to verify I/O count, relay rating, and expansion module compatibility before the part ships — preventing costly field surprises
  • Hard-to-find expansion modules and accessories for the Modicon M221 family can be sourced alongside the base unit to complete the build in a single order
  • Volume pricing is available for OEM and project quantities — contact the team directly to discuss pricing before committing to a build schedule
  • Fast response on stock status and lead time confirmation, reducing the uncertainty that stalls procurement decisions

At-a-Glance Summary

  • Model: TM221CE24R — Modicon M221 logic controller, 24 I/O, relay outputs, Ethernet
  • 14 discrete inputs (4 fast at 5 µs, 10 standard at 35–100 µs) plus 2 analog inputs (0–10V, 10-bit resolution)
  • 10 relay outputs (normally open), 2A per relay; 7A per COM 0/COM 1; 4A per COM 2; 5–250V AC or 5–125V DC rated
  • Relay output switching time: 10 ms turn-on and turn-off; maximum 20 operations per minute at full rated load
  • Mechanical relay durability: more than 20,000,000 contact cycles (no load); electrical life 100,000–300,000 cycles depending on load
  • Supply: 100–240V AC rated, 85–264V AC operating range, single-phase only, 50/60 Hz
  • Power consumption: 35 VA base unit; 58 VA maximum with 7 expansion modules
  • Dimensions: 110 x 70 x 70 mm; DIN-rail IEC 60715 TH35-7.5 or TH35-15
  • Expandable: up to 7 additional I/O modules (transistor or relay output types)
  • No analog outputs, no transistor outputs, no safety-rated contacts on this base model
  • Compliance: EN/IEC 60664-1, EN/IEC 61131-2, EN/IEC 61010-2-201

You may also be interested in: