Ensure safe lifting with confidence
Tamtron’s Overload Protection Unit (OPU) keeps lifting operations safe, controlled and predictable by actively preventing equipment overloads and structural stress. It stops the lifting motion the moment a load exceeds the safe limit or gets stuck, protecting both machinery and operators. OPU can be installed easily, thanks to its compact, DIN-rail compatible design, and you can integrate it smoothly into cranes, hoists, elevators, lifters and other machinery through its versatile input and output connections.
In demanding industrial conditions, OPU delivers precise, real-time supervision. It maintains reliable performance through a rugged build that withstands heavy daily use. The system continuously checks sensors, cables and operational status with automatic diagnostics, keeping the operator aware of any issue as it arises. When OPU detects overload or unexpected resistance, it stops the lift immediately to prevent equipment damage and unsafe situations.
Key benefits
- Prevent damage with automatic lifting stop
- Install easily on both new and existing equipment
- Calibrate and configure effortlessly
- Monitor lifting operations with continuous automatic diagnostics
- Store the highest overload score for clear reporting and traceability
- Track load stress to optimize lifecycle maintenance

The Overload Protection Unit also gives you detailed insights into every overload event. It records event data, including date, time and load information, so you can review incidents, report them clearly and track long-term patterns. With built-in load tracking, you can follow cumulative stress levels and schedule maintenance based on real data, reducing downtime and avoiding premature wear.
When you need additional stability, OPU supports stability control to prevent unbalanced lifting or tipping risks. You can connect the system to PLC automation through the optional 4–20 mA signal amplifier, enabling seamless use in both modern and existing equipment setups. With these capabilities, Tamtron’s Overload Protection Unit helps to improve safety, extend equipment lifecycle and strengthen operational efficiency across all lifting environments.
| SCALE SPECIFICATIONS | |
|---|---|
| Dimensions | 104 mm × 90 mm × 62 mm (W × H × D) |
| Operating voltage | AC input: 100–240 VAC, 50/60 Hz, 15 W DC input: 10–30 VDC, 12 W |
| Relay outputs | 3 pcs of SPDT, 250 VAC, 16 A |
| Load cell inputs | 2 pcs of strain gauge inputs 4/6-wire Excitation voltage: 5 VDC, 90 mA max Signal level: ±10 mV max |
| AD-converter | 24-bit delta-sigma |
| Analog outputs | 4–20 mA, user-programmable level or 0–10 V, user-programmable level |
| Digital inputs | 2 pcs of optically isolated 4–30 VDC inputs |
| Real time clock | Real-time clock and calendar with battery backup |
| Load tracking | Non-volatile memory for 250 time counters Maximum load capture with time stamp |
| Connectivity | USB-A: Flash memory stick, parameters, load tracking USB-B: Firmware update RS-485: Isolated data link for external OPU RS-232: Isolated external display data output |
| Local display | 20 characters per row, 2 rows, backlight |
| Keyboard | 5 push buttons |
| External display | 6-digit 7-segment red, 125 mm segment height |
| IP classification | IP20 (IP66 enclosure available) |
| Operating temperature | -30 °C … +60 °C |
| OPTIONS | |
|---|---|
| External display | Option |
| Plastic protective case | Option |



Load cells – standard delivery or tailor-made
Load cells are used as a part of the weighing system and to prevent overloading. The high security factor ensures the load cells withstand demanding conditions. We produce both standard load cells as well as customer-specific tailored load cells. Application-specific, tailored products include for example tension load cells, axle load cells, chain load cells, bending load cells and compression load cells.
Download brochure
Discover how the Tamtron Overload Protection Unit (OPU) improves lifting safety and operational reliability by actively preventing overloads and structural stress. Download the brochure to explore features, modes and integration options in detail.
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