Schneider TM2DMM8DRT Discrete Input/Output Module

Description

The Schneider Electric TM2DMM8DRT is a mixed Discrete I/O module engineered for reliable expansion of Modicon M238 control systems. It combines four digital inputs and four relay outputs in a compact form, giving machine builders a practical way to integrate sensors and actuators without adding multiple separate modules. Moreover, its robust isolation levels and proven relay durability make it a trusted choice in industrial environments that demand continuous operation. The module installs easily on a 35 mm DIN rail and integrates smoothly into existing architectures, allowing engineers to scale systems with confidence.

Functional Highlights

The TM2DMM8DRT supports both sink and source digital inputs, which simplifies wiring choices during retrofit or system expansion projects. In addition, each relay output delivers up to 2 A per channel, which allows direct control of small loads and contactor circuits. Its fast response time improves machine cycle performance, while the module’s broad compatibility with Twido and Advantys OTB systems offers flexibility in mixed-generation installations. Therefore, users benefit from stable performance and reduced engineering effort during commissioning.

Technical Specifications

General

• Manufacturer: Schneider Electric

• Series: TM2 Expansion Modules

• Product Type: Discrete Input/Output Module

• Part Number: TM2DMM8DRT

Inputs

• Quantity: 4 digital inputs

• Voltage: 24 VDC

• Input Voltage Range: 20.4…28.8 VDC

• Logic Type: Sink or Source

• Input Current: 7 mA per channel

• Input Impedance: 3.4 kΩ

• Response Time: 4 ms (state 0), 4 ms (state 1)

Outputs

• Quantity: 4 relay outputs (1 NO contact each)

• Max Output Current: 2 A per channel

• Max Current per Common: 7 A

• Minimum Switching Current: 0.1 mA at 0.1 VDC

• Contact Resistance: 45 mΩ

• Response Time: ≤10 ms (0→1), ≤5 ms (1→0)

Isolation

• Inputs to Logic: 500 V for 1 minute

• Outputs to Logic: 2300 V for 1 minute

• Between Input and Output Groups: 1500 V for 1 minute

• Between Output Groups: 1500 V for 1 minute

Durability

• Mechanical Life: 20 million cycles

• Electrical Life: 100,000 cycles at rated loads

Physical

• Mounting: DIN-rail (35 mm)

• Terminal Block: Removable screw terminal

• Dimensions: 84.6 × 27.3 × 90 mm

• Weight: 0.095 kg

Typical Applications

This module suits small and mid-sized machines where mixed I/O requirements must be addressed within limited panel space. For instance, OEMs use it in packaging equipment, material handling lines, compact conveyors, and small process skids. Moreover, system integrators deploy it in retrofit projects that require simple relay switching combined with 24 VDC sensing. Its compatibility across multiple Modicon platforms ensures long-term usability, even as newer PLC families like the Modicon TM3 replace older TM2 modules.

Support & Maintenance

Routine inspection of relay contact wear helps maintain long-term reliability, especially in applications with frequent switching. Additionally, the removable terminal block simplifies field replacement, which reduces downtime during maintenance activities. Schneider Electric provides full documentation, including datasheets, user guides, and wiring drawings, to support integrators throughout the product lifecycle.

FAQ

Q1: Is the TM2DMM8DRT still available for purchase?
The module is discontinued, but many distributors continue to offer stock. The recommended replacement series is the Modicon TM3 I/O modules.

Q2: Can the TM2DMM8DRT be used with Modicon M221 or M251 controllers?
It is primarily designed for M238, Twido, and Advantys OTB systems. For M221/M241/M251, Schneider recommends TM3 modules.

Q3: What loads can the relay outputs directly drive?
The outputs support up to 2 A resistive and are suitable for coils, solenoids, lamps, and small relays.

Q4: Does the module support both sourcing and sinking digital inputs?
Yes, the input circuitry accepts either sink or source wiring, improving integration flexibility.

Q5: What is the expected relay lifespan in typical applications?
The relays provide 20 million mechanical cycles and 100,000 electrical cycles at rated conditions.