Description

The Siemens 6EP1961-2BA21 is a SITOP PSE200U selectivity module (electronic circuit breaker) that distributes a 24V DC supply to four independently protected output channels, each adjustable from 3A to 10A . It is designed to act as a “smart fuse” in industrial control cabinets, replacing traditional thermal breakers with precise, resettable electronic protection.

As a core component of the SITOP Power Security portfolio, the Siemens 6EP1961-2BA21 ensures that a fault on one load (e.g., a short circuit in a sensor) does not cascade and shut down the entire system. By selectively disconnecting only the affected channel, it preserves the operation of all other critical loads connected to the same power supply.

 

Application Scenarios

In a large automotive stamping press, control engineers struggled with a recurring nightmare: a single faulty proximity switch would short-circuit, causing the entire 24V PLC rack to lose power and halt the multi-million dollar press line. The installation of the Siemens 6EP1961-2BA21 transformed this scenario . By connecting the main 24V supply to the module and distributing power to the PLC, HMI, field sensors, and actuators on four separate channels, a short on any one device now only trips its dedicated channel. The PLC and HMI remain powered, allowing operators to receive a clear diagnostic message (via the group signal contact) and continue production on other parts of the line while maintenance replaces the faulty sensor.

The Siemens 6EP1961-2BA21 directly addresses the critical industrial pain point of nuisance tripping and difficult fault localization. Its adjustable response threshold (3-10A) per channel allows fine-tuning to match the inrush currents of inductive loads, preventing unnecessary trips while providing reliable short-circuit protection. The clear per-channel LED status indicators (green for on, red for trip, flashing for overload) make troubleshooting instantaneous, slashing downtime from hours to minutes .

 

Parameters

Main Parameters	Value/Description
Product Model	6EP1961-2BA21
Manufacturer	Siemens
Product Category	Selectivity Module / Electronic Circuit Breaker
Input Voltage	24V DC
Number of Channels	4
Output Current per Channel	3…10A (independently adjustable)
Output Voltage	22…30V DC
Total Input Current	40A (max.)
Mounting	DIN rail (EN 60715)
Electrical Connection	Screw terminals (0.2-6 mm²)
Operating Temperature	0°C … +60°C
Storage Temperature	-40°C … +85°C
Dimensions	72mm x 80mm x 72mm (WxHxD)
Weight	~0.22 kg
Certifications	CE, cULus Listed (UL 508, CSA C22.2), CB, EAC

 

Technical Principles and Innovative Values

• Innovation Point 1: Selective Disconnection with Adjustable Thresholds. The Siemens 6EP1961-2BA21 goes beyond simple fusing. It features electronic current monitoring per channel that can be set between 3A and 10A via an intuitive dial . The module implements a precision shutdown characteristic: it allows 101-129% of the set current for up to 5 seconds (handling motor inrush) but shuts down within 50-100ms at >130% of the threshold (short-circuit protection) . This ensures only the faulty circuit is isolated, keeping the rest of the system operational—a critical advantage over single-point fuses.
• Innovation Point 2: Intelligent Status Signaling and Remote Reset. The Siemens 6EP1961-2BA21 provides comprehensive diagnostic intelligence. Each channel has a bi-color LED (green/red) . Additionally, a group signal contact (changeover relay) provides a remote indication if any channel has tripped . More importantly, it features a “Remote Reset” input (RST), allowing a PLC or SCADA system to acknowledge a fault and re-energize a channel remotely . This eliminates the need for physical intervention to reset a breaker, a major efficiency boost for unmanned or remote facilities.
• Innovation Point 3: Integrated Serial Status Output for PLC Integration. Unlike simpler distribution blocks, the Siemens 6EP1961-2BA21 provides a serial status output (S) that transmits the on/off status of all four channels in a data frame . Siemens provides a ready-to-use function block for SIMATIC controllers, enabling seamless integration into the plant’s diagnostic architecture. This “plug-and-play” intelligence transforms the module from a passive protector into an active component of the automation system.