6ES7313-5BE00-0AB0 24V DC CPU 313C Compact PLC

Introduction: The 6ES7313-5BE00-0AB0 Compact CPU for Space-Constrained Automation

When control cabinets run out of space and wiring complexity drives up costs, the 6ES7313-5BE00-0AB0 from Siemens offers a practical solution. This SIMATIC S7-300 CPU 313C compact CPU packs digital and analog I/O, high-speed counting, and a power supply into a single 120 mm wide module. Consequently, engineers can reduce panel footprint and simplify installation while maintaining robust control performance.

For applications that demand fast response and integrated I/O, this CPU delivers a balanced mix of processing power and onboard functionality. With 32 kbyte of integrated work memory and a real-time clock, it suits small to medium machines that require reliable logic, timing, and data handling.

Key Features and Technical Specifications of the 6ES7313-5BE00-0AB0

The 6ES7313-5BE00-0AB0 is designed to handle a wide range of control tasks without the need for separate I/O modules. Its integrated digital and analog channels reduce hardware costs and simplify commissioning. Below are the core specifications extracted from the official datasheet:

• Supply voltage: Rated 24 V DC, permissible range 20.4 V to 28.8 V DC.
• Digital inputs: 24 inputs, rated voltage 24 V DC, signal "1" at +15 to +30 V, signal "0" at -3 to +5 V.
• Digital outputs: 16 outputs, short-circuit protected, signal "1" min. L+ (-0.8 V), max. output current 500 mA per output.
• Analog inputs: 4 channels for voltage/current, 1 for resistance thermometer (Pt100).
• Analog outputs: 2 channels, voltage or current ranges.
• Fast counters: 3 counters with max. counting frequency 30 kHz.
• Working memory: 32 kbyte integrated, not expandable.
• Load memory: Expandable via Micro Memory Card (MMC) up to 4 Mbyte.
• Power loss: Typical 14 W.
• Dimensions: 120 mm x 125 mm x 130 mm; weight approx. 660 g.

One distinctive feature is the integrated 24 V DC power supply, which simplifies the system design by eliminating an external power module. Additionally, the 3 fast counters (30 kHz) enable precise speed or position monitoring without extra high-speed modules.

Real-World Applications for the 6ES7313-5BE00-0AB0

This compact CPU is well suited for small packaging machines, material handling systems, and specialized test rigs where space is at a premium. The integrated analog I/O allows direct connection of sensors and actuators, reducing the need for additional signal conditioners.

Because the CPU supports MPI communication with up to 8 connections, it can act as a server for S7 communication, enabling data exchange with HMIs or other controllers.

In retrofit projects, the 6ES7313-5BE00-0AB0 can replace older, less capable CPUs while reusing existing field wiring, provided voltage and signal levels match.

Installation and Setup: Getting the 6ES7313-5BE00-0AB0 Running

Mounting the CPU on a standard S7-300 rail is straightforward. The module fits into a rack with up to 31 modules, and you can add up to 3 expansion units via the backplane bus. Ensure the 24 V DC supply is within the permissible range of 20.4 V to 28.8 V to avoid operational issues.

For digital inputs, use shielded cables up to 1000 m (or 100 m for technological functions) and unshielded up to 600 m. Outputs have the same cable length limits. Remember that the CPU requires a Micro Memory Card (MMC) for program storage; without it, the CPU cannot operate.

Configuration is performed with STEP 7 software (V5.1 SP2 or later). The CPU supports LAD, FBD, STL, SCL, GRAPH, and HiGraph® programming languages, giving engineers flexibility in developing control logic.

Maintenance and Reliability: Keeping the CPU 313C in Service

The 6ES7313-5BE00-0AB0 is designed for long-term industrial use, but periodic checks help prevent unexpected downtime. Verify that the supply voltage remains within the specified range and that ambient temperature does not exceed the module's rating (refer to the datasheet for exact limits).

Because the CPU has no battery for backup, the MMC provides maintenance-free retention of program and data. This eliminates battery replacement tasks and reduces maintenance cost. Still, it is wise to keep a backup of the project file on a separate storage medium.

Inspect connectors and wiring annually for signs of corrosion or loose terminations. Clean the module enclosure with a dry cloth only; do not use solvents or compressed air that could damage components.

Compatibility and Integration of the 6ES7313-5BE00-0AB0

This CPU communicates via MPI with a maximum transmission rate of 187.5 kbit/s. It supports PG/OP communication, global data communication, and S7 communication (as server). Up to 8 connections are available, with 7 usable for PG and 7 for OP communication.

For fieldbus connectivity, you can add a CP (communications processor) to act as a PROFIBUS DP master, but the CPU itself does not have a built-in DP interface. The module also supports S7 basic communication with up to 4 connections.

When integrating with existing S7-300 systems, ensure that the MMC type and STEP 7 version are compatible. The CPU can be used in a multi-rack configuration with up to 3 expansion units, providing scalability for larger applications.

Troubleshooting Common Issues with the 6ES7313-5BE00-0AB0

If the CPU fails to start, check that the MMC is inserted correctly and that the supply voltage is present. A missing or corrupted MMC will prevent operation. Also, verify that the 24 V DC supply is not below 20.4 V, which can cause erratic behavior.

For digital input problems, confirm that the signal levels meet the specified thresholds: signal "1" requires +15 to +30 V, while signal "0" is -3 to +5 V. If inputs are floating, they may read incorrectly; use appropriate pull-up or pull-down resistors as per Siemens guidelines.

Output short circuits are protected electronically, but repeated trips may indicate a wiring fault. Check the output group's total current limit: up to 8 A at 40 °C and 4 A at 60 °C. Exceeding these values can damage the module.

For analog input accuracy, ensure that the integration time is set appropriately (2.5, 16.6, or 20 ms) to reject noise. The basic error limit is ±0.7% for voltage and current, and ±3% for resistance measurements.

Availability and Support

The Siemens 6ES7313-5BE00-0AB0 is available from AutoDCSTech. Contact our team to check current stock and lead times.