Product Overview

The Schneider Electric TM2DRA16RT is a 16-channel relay output module for the Modicon M238 logic controller. It provides relay-based switching for connecting PLC control outputs to external electrical loads, including contactors, indicator devices, solenoid valves, and other industrial actuators.

Unlike transistor output modules, the TM2DRA16RT uses electromechanical relay contacts. Each output provides one normally open (NO) contact, allowing the controller to switch compatible AC or DC loads. The module has two common terminal groups, with eight output channels assigned to each group.

Each relay channel supports a maximum switching current of 2 A, while the maximum current per common group is 8 A. This arrangement allows the module to control different loads while maintaining separate common connections.

The removable screw terminal block simplifies field wiring and makes it easier to disconnect the output wiring during maintenance or module replacement. Individual output states can be monitored through the module’s local indication.

The TM2DRA16RT is suitable for Modicon M238 installations requiring relay-based output switching, particularly where the connected equipment operates at different voltage levels or requires electrically isolated switching contacts.

Technical Specifications

Product Features

• 16 Relay Output Channels: Provides 16 independent normally open relay contacts for controlling external electrical loads.
• AC and DC Switching: Supports compatible AC and DC output applications within the specified voltage and current limits.
• Two Common Groups: Divides the 16 outputs into two groups of eight, allowing separate common connections.
• 2 A Per-Channel Rating: Each relay output supports a maximum current of 2 A.
• Electrical Isolation: Provides isolation between output channels and internal logic to separate field-side switching circuits from controller electronics.
• Removable Screw Terminal: Allows convenient field wiring and simplifies maintenance operations.
• DIN Rail Installation: Supports mounting on a standard 35 mm symmetrical DIN rail.
• Relay Status Indication: Includes local indication for checking output operation.
• Long Mechanical Service Life: Relay contacts have a specified mechanical durability of 20 million cycles.

Product Working Principle

The TM2DRA16RT converts digital control commands from the Modicon M238 controller into electrical switching actions through its 16 electromechanical relay channels.

Its operation involves several stages.

1. Controller Output Command

The Modicon M238 executes its control program and determines which relay outputs need to be activated according to the machine or process conditions.

2. Internal Relay Activation

When an output command is issued, the corresponding internal relay coil is energized through the module’s control circuitry.

3. Contact Switching

The relay’s normally open contact changes to its closed state, allowing current to flow through the connected external circuit.

4. Load Operation

The switched circuit supplies the connected load, such as a contactor coil, solenoid valve, or indicator device. When the controller removes the output command, the relay returns to its normally open state.

5. Independent Output Groups

The 16 outputs are arranged into two common groups. Each group contains eight channels, and the two common groups are not internally connected to each other.

6. Output Monitoring

The module provides local indication for monitoring output conditions. Maintenance personnel can use these indicators alongside controller diagnostics to identify switching or wiring problems.

A simplified control arrangement is:

Modicon M238 Controller → TM2DRA16RT → Relay Contacts → External Electrical Loads

Because the module uses electromechanical relays, its switching characteristics and electrical durability must be considered when selecting loads and determining switching frequency.

Role in Schneider Modicon M238 Control Architecture

Within a Modicon M238 automation system, the TM2DRA16RT serves as the relay-based output interface between the PLC and external electrical equipment.

The controller processes input signals and executes application logic, while the TM2DRA16RT performs the physical switching required to operate connected loads.

Its two common groups allow different output circuits to be wired separately, which is useful when a machine contains several groups of actuators or equipment operating on different supply circuits.

Industrial Applications

The TM2DRA16RT is used in machine automation systems where PLC-controlled relay switching is required.

Installation and Maintenance

1. Verify the Model Number: Confirm that TM2DRA16RT is the required 16-channel relay output module for the Modicon M238 system.
2. Check Load Requirements: Verify that each connected load operates within the module’s voltage and current ratings.
3. Disconnect Power: Switch off the controller and external load supplies before installing or removing the module.
4. Inspect the Module: Examine the terminal block, relay contacts, housing, and connection points for visible damage.
5. Prepare the DIN Rail: Ensure that the 35 mm symmetrical DIN rail is securely installed and suitable for the module assembly.
6. Install the Module: Mount the TM2DRA16RT according to the controller and expansion system installation instructions.
7. Connect Output Wiring: Wire the external loads to the appropriate relay output terminals, observing the two common groups.
8. Install Protective Fuses: Provide appropriate overcurrent protection for the external load circuits.
9. Protect Inductive Loads: Use suitable external suppression circuits when switching inductive AC loads to reduce relay contact damage.
10. Check Terminal Connections: Verify wiring polarity where applicable, terminal tightness, conductor ratings, and electrical separation between circuits.
11. Configure the Controller: Assign the output channels in the application program and verify that the controller configuration matches the installed hardware.
12. Perform Functional Testing: Restore power and test each output channel individually, checking relay operation, load response, and local status indication.

Compatible System Components

Recommended Related Models

Key Advantages

• Provides 16 relay output channels in one module.
• Supports compatible AC and DC switching applications.
• Offers two electrically separate common groups.
• Supports a maximum switching current of 2 A per channel.
• Provides isolation between output circuits and internal logic.
• Uses removable screw terminals for field wiring.
• Supports standard 35 mm DIN rail mounting.
• Integrates with Modicon M238 control systems.

Technical FAQs

1. Are all 16 outputs on the TM2DRA16RT independent?

The module has 16 relay output contacts divided into two common groups. Each group contains eight channels. The two common groups are not internally connected, allowing separate external circuit connections.

2. Can the TM2DRA16RT switch both AC and DC loads?

Yes. Its relay contacts support compatible AC and DC applications. The rated voltage is 24 V DC or 230–240 V AC, with a maximum current of 2 A per channel. The load type and switching frequency must also remain within the specified electrical durability limits.

3. Can the TM2DRA16RT directly control inductive loads?

It can switch suitable inductive loads within its electrical ratings, but external protective circuits are required for inductive AC loads to reduce contact damage. Capacitive loads are not supported.

4. What is the difference between TM2DRA16RT and a transistor output module?

The TM2DRA16RT uses electromechanical relay contacts, allowing it to switch compatible AC and DC circuits. Transistor output modules use semiconductor switching and are generally more suitable for applications requiring higher switching frequencies. The choice depends on load type, voltage, switching speed, and service-life requirements.