Low Voltage Automatic Transfer Switch: TW581 Series Guide
In modern power distribution systems, ensuring uninterrupted power supply is critical. The TW581 series low voltage automatic transfer switch (also known as an automatic transfer switch controller or backup power switching device) is designed to handle main and backup power source switching for systems up to 690V. With an integrated 32-bit PLC and a 4-inch color display, it provides real-time monitoring, voltage measurement, digital I/O, and network communication in one compact unit.
Key Features of the TW581 Series ATS Controller
- ▶ Compact Design for Various Switchgear: The ultra-small form factor fits GCK, GCS, GGD, MNS withdrawable (including 1/4 drawer), fixed, and hybrid cabinets. This makes installation easy in tight spaces while saving wiring and improving safety.
- ▶ 4-Inch Color LCD Display: The intuitive human-machine interface shows the primary system diagram, analog values, and switch statuses. Parameters and settings can be adjusted directly on the screen.
- ▶ Advanced Embedded Technology: Built on a System-on-Chip (SOC) design with DSP and redundant fieldbus. AC sampling uses optimized full-wave FFT algorithms for accurate measurements. The modular software is highly resistant to interference.
- ▶ Built-in PLC with Flexible Logic: Multiple automatic transfer logic schemes are pre-programmed. Users can set various timing parameters (e.g., transfer delay, restore delay) to match specific application needs. Options for power-on auto-transfer and charging process selection are available.
- ▶ Manual Mode with Safety Logic: In manual operation, the device performs logic checks to prevent dangerous paralleling of sources due to operator error (supported on select models).
- ▶ LED Status Indicators: Power, communication, operating condition, and alarm LEDs provide quick visual diagnostics for maintenance.
- ▶ Extensive I/O Capacity: Supports up to 4 voltage acquisition channels, 14 digital inputs, and up to 10 digital outputs for comprehensive control.
- ▶ Open Communication: Standard RS-485 interface with Modbus protocol allows integration with PLCs from major brands (Siemens, Schneider, GE, AB) and SCADA software (KingView, FIX, WinCC, InTouch). Remote monitoring and data management are easily achieved.
Hardware Configuration
The TW581 system consists of three main components:
- Main ATS Controller Unit – designed for DIN rail mounting (35mm) or flat surface mounting with screws.
- 4-inch Color LCD Display Panel – mounts on the cabinet door for local monitoring and configuration.
- Communication Cable – connects the display panel to the main unit via DB9 and MID8 connectors.
Installation Guidelines
Surface Mounting
Drill two 4mm holes according to the mounting dimensions. Secure the main unit with screws directly onto the panel.
DIN Rail Mounting
Install a standard 35mm DIN rail on the panel. Snap the main unit onto the rail for quick and secure mounting.
Display Panel Mounting
Cut two 3mm holes and one 18mm hole on the cabinet door as per the template. Fix the display with the supplied stainless steel screws. Connect the communication cable from the main unit’s DB9 to the display’s MID8 port.
Typical Applications
The TW581 series is widely used in low voltage distribution systems where reliable backup power is essential:
- Power plants and substations
- Industrial plants and mining operations
- Public utilities and water treatment facilities
- Commercial buildings and intelligent skyscrapers
- Railway signaling and infrastructure
For sites without UPS or DC panel supply, a single-phase dual power transfer module (model TW58A) can be paired with the TW581 to provide a cost-effective complete solution.
Technical Specifications at a Glance
| Parameter | Specification |
|---|---|
| Rated Voltage | Up to 690V AC |
| Control Core | 32-bit PLC with DSP |
| Display | 4-inch color LCD |
| Voltage Inputs | Up to 4 channels |
| Digital Inputs | 14 channels |
| Digital Outputs | Up to 10 channels (configurable) |
| Communication | RS-485, Modbus RTU |
| Mounting | DIN rail (35mm) or screw fixing |
| Compatible Cabinets | GCK, GCS, GGD, MNS, etc. |
Why Choose a PLC-Based Automatic Transfer Switch?
Traditional relay-based ATS controllers often lack flexibility and diagnostic capabilities. A PLC-based design like the TW581 offers programmable logic, allowing customization of transfer sequences, time delays, and alarm settings. The integrated power metering and communication enable predictive maintenance and energy management. This reduces downtime and improves overall system reliability.
The TW581’s ability to network with SCADA systems means operators can monitor source status, voltage levels, and switch position from a central control room. In critical facilities such as hospitals or data centers, this visibility is invaluable.
Note:
Always refer to the manufacturer’s installation manual for detailed wiring diagrams and safety precautions. Proper coordination with upstream circuit breakers and downstream loads is essential for safe operation.
