Siemens 6ES5928-3UB12 CPU928B Central Controller | CPU928B Module

Siemens 6ES5928-3UB12 CPU928B Central Controller

The 6ES5928-3UB12 CPU928B runs fast tasks and supports large programs.
It fits S5-135U and S5-155U units and works well in single or multi-CPU systems.
Author: Powergear X Automation

Main Highlights

• The controller supports up to four CPUs inside one S5 rack.
• It runs bit and word tasks with very fast speed.
• The module supports cyclic, timer, real-time, interrupt and delay modes.
• It works with STEP 5 programming for fast logic work.
• Two PCBs form the full module and stay fixed together.

System Use & Structure

• The device links to the S5 backplane through two connectors.
• The front width equals 2 2/3 plug-in stations.
• The module needs RAM or EPROM submodules for program storage.
• It offers up to 64 × 2¹⁰ bytes user memory and 46 × 2¹⁰ bytes DB RAM.
• The **CPU928B** supports optional serial modules such as V.24, RS422A/485 and TTY.

Interface & Operation

• The PG interface SI1 stays fixed on the front panel.
• You may access SI1 from the CPU front or the 923C module.
• The mode switch has RUN and STOP positions for simple control.
• Overall Reset clears all RAM and restarts fully.
• Reset clears flags, timers and counters and runs OB20.
• Restart continues the program from the last break point.

Electrical Data

• Supply: 5 V ±5% and 24 V +25% / -17%.
• 5 V current draw: 5 A typical.
• 24 V current draw: 760 mA max.
• Backup voltage: 3.4 V, backup current: 20 µA at 25°C.
• PG serial rate: 9600 bps.

Internal Capacity

• Flags: 2048 units.
• S Flags: 8192 units.
• Timers: 256 units.
• Counters: 256 units.
• PB, SB, FB, FX: Each supports 256 blocks.
• DB and DX: 256 blocks each, 253 free for user work.
• OB: OB1 to OB39 supported.

Environmental & Mechanical

• Degree of protection: IP00.
• The controller follows S5-135U/155U ambient rules.
• Strong EMC immunity based on S5 system specs.
• Size: 40.64 × 233.4 × 160 mm.
• Net weight: 0.991 kg.
• Outer pack size: 25.9 × 20.8 × 5.5 cm.

Why Choose the 6ES5928-3UB12 CPU928B

• It supports stable long-term industrial use.
• It handles large logic and high I/O counts.
• It gives clear LED states for quick checks.
• It offers simple reset modes for fast recovery.
• It works with many S5 modules for flexible system design.

Warranty & Shipping

• We offer a full 12-month warranty on every unit.
• We ship worldwide by FedEx, UPS and DHL.
• Each unit comes in safe industrial packing.

FAQ

• Q: How do I choose the right memory submodule?

  A: Use RAM for changes and EPROM when you want a fixed stable program.

• Q: What helps keep the CPU stable in multi-CPU mode?

  A: Keep short bus paths and match firmware versions across CPUs.

• Q: How do I avoid faults when switching modes?

  A: Stop the CPU, check LEDs, then move the switch to RUN slowly.

• Q: What improves long-term contact reliability at SI1?

  A: Clean the connector lightly and avoid strong cable bends.

• Q: How should I test after a cold start?

  A: Run short logic cycles, check timers and counters, and verify I/O updates.

Contact Information

• Email us at sales@powergearx.com
• WhatsApp: +86 18030005825

Copyright © 2025 Powergear X Automation Limited. All rights reserved.
Original Source:
https://www.powergearx.com/