Siemens PXC5.E003 Programmable Controller for Building Automation

The Siemens PXC5.E003 is a compact programmable controller from the Desigo PXC series, designed for building automation systems (BAS). It integrates seamlessly into BACnet/IP networks, providing control for HVAC, lighting, and other building services. The model includes a BPZ (building automation) label, indicating its application in Siemens' comprehensive automation ecosystem.

Processing and Memory

The controller features a 32-bit processor with 16 MB RAM and 64 MB flash memory. It runs the Desigo system software, supporting up to 250 data points and 50 control loops. Programming is accomplished using Siemens' ABT (Automation Builder Tool) software, which complies with IEC 61131-3 (ladder, function block, structured text).

Inputs and Outputs

The PXC5.E003 provides 10 built-in I/O points: 4 universal inputs (0-10V, 4-20mA, PT1000, Ni1000, or digital), 4 digital inputs (dry contact), and 2 relay outputs (24V AC/DC, 2A). All I/O are electrically isolated. Expansion via I/O modules is possible through the local bus, supporting up to 120 additional points.

Communication

Primary communication is BACnet/IP over a built-in Ethernet port (10/100 Mbps). A secondary RS-485 port supports BACnet MS/TP or Modbus RTU for connecting field devices. The controller also includes a USB port for local commissioning. It acts as a BACnet Building Controller (B-BC) per BACnet standard.

Power Supply

Operates on either 24V AC (±15%) or 24V DC (±20%). Power consumption is typically 10 VA (AC) or 7 W (DC). The controller includes a real-time clock with supercapacitor backup providing 72 hours of runtime during power loss. No external battery is required.

Environment and Mounting

Rated for operating temperatures 0°C to 50°C, humidity 10% to 90% non-condensing. It mounts on standard DIN rail or directly to a wall. Dimensions are 158 x 110 x 61 mm (W x H x D). The plastic housing is flame-retardant and meets UL 94 V-0.

Cyber Security

Siemens implements security features such as HTTPS, encrypted communication (TLS 1.2), user role-based access, and port lockdown. The controller supports digital certificates for secure BACnet connections. Firmware updates are digitally signed.

Applications

Typical building automation applications include air handling units (AHUs), variable air volume (VAV) boxes, chiller plant optimization, lighting control, and room automation. The compact size and built-in I/O make it suitable for standalone or networked operation.

Conclusion

The Siemens PXC5.E003 (BPZ) controller delivers powerful, BACnet-native programmability for building automation. Its 10 I/O points, Ethernet communication, and robust construction provide a cost-effective solution for modern smart buildings.