Modicon Twido TWDDI16DT

The Modicon Twido TWDDI16DT is a 16-point Digital Input Expansion Module specifically for the legacy Twido PLC series (now under Schneider Electric).

While it looks very similar to the TM2 series, it is part of the original Twido-specific expansion line. It is used to add discrete 24V DC inputs (such as sensors, switches, or encoders) to a Twido base controller.

1. Input Configuration

The “DT” designation identifies this as the standard model with Screw Terminal Blocks, which are generally preferred for ease of field wiring without specialized cables.

• Number of Inputs: 16.

• Input Voltage: 24V DC.

• Input Type: Sink/Source (Logic is defined by the user’s wiring of the “Common” terminal).

• Connection Type: Non-removable screw terminals (on most older versions) or removable terminals (on late-stage production units).

2. Technical Specifications

3. Wiring: Sink vs. Source

The flexibility of the TWDDI16DT allows it to work with NPN or PNP sensors depending on how you wire the COM terminal:

• Source Logic (Positive Logic): Connect 0V to the COM terminal. When a sensor sends +24V to an input, the PLC registers it as “1”.

• Sink Logic (Negative Logic): Connect +24V to the COM terminal. When a sensor pulls an input to 0V (GND), the PLC registers it as “1”.

4. Key Features

• Direct Wiring: Unlike the “TK” or “DK” versions, this module allows you to land wires directly from your sensors onto the screw terminals.

• Individual Status LEDs: Each of the 16 inputs has its own green LED indicator on the front panel, allowing for fast physical troubleshooting of sensor signals.

• High Isolation: With 1500Vrms isolation, this module provides significant protection to the PLC CPU against external electrical noise or surges.

5. Legacy & Compatibility Note

The TWDDI16DT is a Legacy product.

• Twido vs. TM2: Most Twido PLCs can also accept the newer TM2DDI16DT modules. However, the TWD series was the original matching hardware for the TWD Compact and TWD Modular bases.