Product Introduction
With 16 isolated digital inputs and a wide input voltage range of 120/230 V UC, the Siemens 6ES7421-1FH20-0AA0 delivers robust performance for demanding industrial automation environments. This SIMATIC S7-400 SM 421 module conforms to IEC 61131 Type 2, making it ideal for direct connection to AC/DC sensors. Its low power loss of 12 W typ. reduces heat generation and operational costs.
Technical Specifications Breakdown
Key parameters of the Siemens 6ES7421-1FH20-0AA0 include:
- 16 digital inputs, isolated in groups of 4
- Input voltage: 120/230 V UC (47–63 Hz); signal "0" 0–40 V AC / -40 to +40 V DC; signal "1" 74–264 V AC / 80–264 V DC
- Input current for signal "1" typ. 10 mA at 120 V (AC) and 1.8 mA (DC)
- Input delay max. 20 ms (0→1) and 30 ms (1→0) for AC
- Power loss typ. 12 W
- Diagnostics function: No
- Isolation tested with 1500 V AC
Industry Applications
The Siemens 6ES7421-1FH20-0AA0 excels in applications requiring high-voltage AC sensing, such as power distribution monitoring, motor control centers, and conveyor systems. Its ability to handle both AC and DC inputs simplifies wiring in mixed-signal environments. For example, in a packaging plant, this module can directly interface with 120 V AC proximity sensors without external converters, reducing component count and system complexity.
Installation & Setup Guidance
Mount the Siemens 6ES7421-1FH20-0AA0 on a standard S7-400 rack. Connect via the backplane bus; the module draws a maximum of 80 mA from the 5 V DC bus. Ensure shielded cables (max. 1000 m) for noise-sensitive environments, or unshielded (max. 600 m) for general use. Each input group of four channels is isolated, allowing mixing of different voltage sources within the same module.
Selection Guide & Purchasing Advice
When selecting the Siemens 6ES7421-1FH20-0AA0, verify compatibility with your S7-400 CPU and backplane version. Confirm that the input voltage range matches your field devices. For reliable supply, consider purchasing from PLC Source PRO (available through ubest101.myshopify.com) to ensure genuine Siemens parts and prompt delivery.