NEED-24DC- /T2UK Programmable Relay

The NEED-24DC- /T2UK is a compact programmable relay (also known as a logic module or smart relay) designed for small automation tasks. It combines a programmable logic controller function with an integrated display and keyboard, allowing users to create simple control programs without a PC. Operating on 24 V DC, this device features 16 digital inputs and 8 relay outputs, making it suitable for controlling small machinery, lighting, gates, pumps, and fans. The built‑in LCD screen shows status, variables, and program steps. The keyboard enables on‑the‑fly adjustments and manual override. The "T2UK" suffix may indicate specific firmware or language pack (e.g., English). Programmable relays are an economical alternative to PLCs for applications with fewer than 30 I/O points.

Technical Specifications

Power supply: 24 V DC (19.2‑28.8 V). Consumption: approx. 4 W. Digital inputs: 16 channels, 24 V DC, sink/source configurable (typically common ground or common positive). Input current: 5 mA typical. Response time: adjustable from 1 ms to 50 ms. Outputs: 8 relay outputs (form A, normally open). Contact rating: 8 A at 250 V AC / 30 V DC resistive, 2 A inductive. Output protection: external fuse required. Program memory: 128 KB typical, storing up to 200 function blocks. Execution time: approx. 10 ms for typical program. Display: monochrome LCD, 4 lines × 16 characters or graphical (128 × 64). Keypad: 8‑12 membrane keys for programming and operation. Communication: optional RS‑485 (Modbus RTU) via expansion module. Operating temperature: -10°C to +55°C. Storage: -25°C to +70°C. Dimensions: 110 mm × 90 mm × 60 mm. Protection rating: IP20 (front panel often IP40). Mounting: DIN rail (35 mm).

Key Features

• 16 digital inputs (24 V DC) with adjustable filter

• 8 relay outputs (8 A each) for direct control of loads

• Integrated LCD display for status and programming

• On‑board keypad for parameter editing and manual control

• Programmable using ladder diagram or function blocks (no PC required)

• Real‑time clock for time‑based switching

• Weather data compensation (optional)

• Expandable with communication modules

• Password protection for program security

• DIN rail mounting, compact footprint

Programming and Operation

The device can be programmed either using the built‑in keypad and LCD (no PC needed) or via PC software (if available). On‑device programming involves selecting function blocks (AND, OR, timer, counter, etc.) from a menu and connecting them. Up to 200 function blocks are supported. The LCD shows the circuit diagram in a simplified symbolic form. The real‑time clock allows time‑based events (e.g., switch on at 8:00, off at 17:00) and astronomical clock functions (sunrise/sunset). The program is stored in non‑volatile EEPROM. The front panel also allows manual override of outputs for testing.

Applications

Typical applications include: lighting control (time‑switched and occupancy), small conveyor start/stop, gate and door control, pump alternation (lead‑lag), irrigation controllers, fan control in HVAC, and small industrial machines (drills, grinders). The 16 inputs are sufficient to interface with pushbuttons, limit switches, sensors, and selector switches. The 8 relay outputs can directly drive contactors, solenoid valves, and indicator lights up to 8 A.

Installation and Wiring

Mount the device on a 35 mm DIN rail. Connect 24 V DC power to the + and - terminals. For inputs, connect sensors between the input terminal and the common terminal (common can be 0V or +24V depending on sink/source configuration). For outputs, connect the load between the output terminal and the load supply (separate 24 V DC or 230 V AC). Always fuse each output individually. The device includes removable terminal blocks for easy wiring. After wiring, power up and enter programming mode using the keypad. Configure the inputs as sink or source via a software setting (or DIP switch).

Maintenance and Troubleshooting

No routine maintenance is required. The front LCD may dim over time (backlight life > 50,000 hours). To troubleshoot, check the power LED and the input status LEDs (if present). The program can be read on the LCD to verify logic. If the device fails to start, check supply voltage and external fuses. The device can be reset to factory defaults via the menu. Replace the unit if damaged.

Environmental and Compliance

The NEED-24DC- /T2UK is CE and RoHS compliant. Operating temperature: -10°C to +55°C. Humidity: 10-95% non‑condensing. Vibration: 2g (10‑55 Hz). The device is IP20 and must be installed in a control cabinet.

Conclusion

The NEED-24DC- /T2UK programmable relay offers a cost‑effective, user‑friendly solution for small automation tasks. With 16 inputs, 8 outputs, integrated display, and on‑device programming, it is ideal for machine builders and maintenance personnel who need simple logic control without a full PLC.