Square D BMXCPS3500 PLC Power Supply Module

The Square D BMXCPS3500 is a power supply module for the Modicon M340 programmable logic controller platform from Schneider Electric (formerly branded Square D). This module provides a regulated 3.5A output at 24V DC to power the backplane (CPU, I/O modules, communication modules) and external sensors. It is designed for high efficiency and reliability in industrial automation systems.

Technical Specifications

Input voltage: 24V DC (19.2 – 30 V DC), current consumption ≤ 4.5A at full load. Output: 24V DC (nominal) with a total capacity of 3.5A (84W). The output is divided into two isolated rails: 1.2A for the backplane logic (5V derived internally) and 2.3A for external field devices (sensors, relays). Efficiency > 88% at rated load. The module includes overvoltage, overcurrent, and short-circuit protection with automatic recovery. Hold-up time > 10 ms at 3.5A load. LEDs indicate power good, overload, and fault. Dimensions: 105 mm height x 36 mm width x 85 mm depth (occupies one slot in M340 rack). Weight 0.25 kg. Operating temperature 0°C to 60°C. Storage -25°C to 85°C. Protection rating IP20.

Key Features

• 24V DC input, 3.5A total output

• Dual isolated outputs: backplane + field power

• High efficiency, low heat dissipation

• Short-circuit and overload protection

• LED status indicators for diagnostics

• Hot-swappable (in M340 rack)

• CE, UL, CSA certified

• Rugged design for industrial environments

Compatibility

The BMXCPS3500 fits into the first slot (leftmost) of a Modicon M340 rack (BMX XBP 0800/0600/0400). It supplies power to the backplane for up to 8 I/O modules depending on current consumption. Compatible CPUs include BMX P34 1000, 2000, 3000 series. The field power output (external 24V) can be used to supply up to 8 analog modules or 16 digital modules via the field distribution bus. The module is also compatible with the Modicon X80 range of I/O.

Installation and Wiring

Slide the module into the rack’s guide rails until it clicks into place. Connect the external 24V DC power source to the removable screw terminal block (labeled +24V, 0V, and earth). The terminal accepts wire sizes 0.5 – 2.5 mm² (AWG 20-14). The earth terminal must be connected to the panel ground for EMI compliance. For the field power output, terminals are marked +24V OUT, 0V OUT. These can be used to power sensors or the front connectors of I/O modules. The maximum wire length for field power output is 30 m.

Protection and Diagnostics

The BMXCPS3500 includes a built-in electronic fuse on the field output: if the load exceeds 3.5A or a short circuit occurs, the output shuts down and the “OUT” LED flashes. After removing the fault, the output automatically recovers after 5 seconds. The backplane output has a separate protection circuit; if it fails, the CPU will lose power and the “ERR” LED will illuminate. The status can be read via the CPU’s diagnostic word.

Applications

This power supply is used in Modicon M340 control systems for machine control, packaging lines, material handling, and process automation. Its compact size and high output capacity allow it to power a full rack of I/O modules, eliminating the need for an external power distribution unit. It is also used in redundant power configurations (with two BMXCPS3500 modules and a redundancy kit).

Environmental and Compliance

The BMXCPS3500 meets CE, UL 61010-1, CSA C22.2 No. 61010-1, and ATEX (Zone 2) standards. It is RoHS compliant. The module is designed for pollution degree 2 and overvoltage category II. Vibration resistance: 2g (10-55 Hz). Relative humidity 5-95% non-condensing.

Conclusion

The Square D BMXCPS3500 power supply module delivers reliable, high-efficiency power for Modicon M340 PLC systems. Its dual isolated outputs, comprehensive protection features, and compact form factor make it a core component for industrial automation applications.