Modicon TM3AI8 Analog Input Module – Product Description

Overview

The Modicon TM3AI8 analog input module expands the measurement capability of Modicon M221, M241, M251, and M262 controllers. It captures up to eight analog signals with stable 12-bit resolution, which supports demanding machine-automation tasks. Each channel accepts either voltage or current inputs, allowing flexible integration with industrial sensors. Moreover, its compact design helps engineers build scalable systems without consuming additional cabinet space. The module installs quickly using the TM3 expansion bus, so system growth remains both predictable and cost-efficient.

Technical Specifications

Electrical & I/O

• Supply voltage: 24 VDC via TM3 expansion bus

• Number of analog inputs: 8 channels

• Resolution: 12 bits

• Accuracy: ±0.5% F.S. (typical)

• Input impedance: ≥100 kΩ (voltage), approx. 250 Ω (current)

• Isolation:

• 1500 V AC (input to supply)

• 500 V AC (input to internal logic)

Performance

• Conversion time: 1 ms per channel

• Sampling rate: up to 1 kHz (PLC dependent)

• Diagnostics: module status LEDs

Mechanical

• Dimensions: 23.6 × 90 × 70 mm

• Weight: 0.11 kg

• Mounting: DIN-rail

• Protection rating: IP20

• Connections: removable screw terminals

Environmental & Compliance

• Operating temperature: 0 °C to +55 °C

• Storage temperature: –20 °C to +70 °C

• Humidity: 5–95% non-condensing

• Certifications: CE, UKCA, EAC, RCM, cULus, cULus HazLoc

• Standards: IEC 61131-2, IEC 61010-2-201

• ESD protection: 8 kV air, 4 kV contact 

• Magnetic field immunity: 30 A/m

FAQ

Q1: Which PLCs support the TM3AI8 module?
It works with Modicon M221, M241, M251, and M262 controllers through the TM3 expansion bus.

Q2: Can voltage and current inputs be mixed across channels?
Yes. Each channel can be configured independently for voltage or current measurement.

Q3: Does the module require an external 24 VDC power supply?
No external supply is required for logic; power is taken from the TM3 bus. However, field devices still require their own supply.

Q4: What software is used to configure the module?
Configuration is completed using EcoStruxure Machine Expert – Basic or EcoStruxure Machine Expert.

Q5: Is the module suitable for high-noise industrial environments?
Yes. It includes isolation, EMC-tested immunity, and stable input circuitry that enhance noise resistance.