HIMA HIMax X-MIO 7/6 01 vs Istec SpeedSys® 300
In turbomachinery, overspeed protection is critical to preventing failure and ensuring compliance. To help you come to the best decision in choosing the right system, we’ve put out a comparison. In this comparison, we’ll be looking at the HIMA HIMax X‑MIO 7/6 and the SpeedSys 300.
Why forward-thinking OEMs, integrators, and end users choose SpeedSys® 300
Established brands often continue to build on existing architectures for many years, leaving limited room to incorporate user feedback or modern application requirements. Istec, however, has developed its latest systems from the ground up, with a clear focus on today’s needs in machine protection and monitoring.
As a result, SpeedSys® 300 not only covers the core overspeed protection functions traditionally expected from established solutions, but also extends them with a compact modular design, support for multiple sensor types, configurable outputs, modern communication options, and clearly specified response characteristics. This allows users to implement proven protection concepts while benefiting from additional flexibility and transparency that are increasingly important in both new installations and retrofit projects.
HIMax X‑MIO 7/6
Istec SpeedSys 300
Proven in use
The HIMax X‑MIO 7/6 01 is designed for use in critical turbomachinery applications and is widely applied within HIMA HIMax safety systems for turbine overspeed protection, including API 670‑based installations.
Certified by design
SpeedSys® 300 is designed with functional safety embedded directly into the system architecture. SIL 2 and SIL 3 capability are integral to the product design and depend on the applied redundancy configuration, rather than being added as an external system layer.
(Background on this approach: Het verschil tussen SIL-certificering door ontwerp en proven in use)
System‑integrated protection concept
Overspeed and acceleration protection are implemented within the HIMax system architecture. The X‑MIO 7/6 01 operates as an overspeed trip module within a HIMax PES, using the system bus and baseplate infrastructure.
Standalone protection concept
Each SpeedSys® 300 module performs a complete overspeed protection function independently, clearly separating protection functionality from control and monitoring systems.
Integrated redundancy approach
The module uses three safety‑related measuring inputs and performs an internal 2oo3 evaluation for speed and acceleration. Redundancy is further supported through dual or triple connector boards within the HIMax system.
Modular redundancy approach
Redundancy is achieved by combining multiple SpeedSys® 300 modules, supporting flexible 1oo1, 1oo2, or 2oo3 voting architectures at system level.
Integrated safety outputs
The X‑MIO 7/6 01 provides five safety‑related digital outputs for actuator control. In addition, one non‑safety‑related auxiliary relay is available for signaling and alarms.
Integrated safety I/O
Safety relays and a safety‑related 4–20 mA analog output are available directly on each module, reducing the need for additional external safety hardware.
Backplane‑based system design
The module is installed on a HIMax baseplate using dedicated connector boards and operates as part of the HIMax rack‑based system architecture.
Standalone and distributed installation
SpeedSys® 300 is installed as an individual DIN‑rail mounted device. Multiple units can be mounted side‑by‑side to implement redundancy concepts without requiring a shared rack, backplane, or central baseplate.
Communication for diagnostics
Diagnostics and status information are available via the HIMax system bus and are configured and monitored using the SILworX engineering tool.
Communication for diagnostics
Modbus RTU over RS‑485 is provided for monitoring and diagnostics only and is not part of the safety function.
System‑level protection architecture
Although the trip logic runs within the module itself, the X‑MIO 7/6 01 functions as part of the overall HIMax safety system and depends on the HIMax infrastructure for configuration, communication, and redundancy management.
Compact and practical design
The compact footprint supports space‑constrained installations and retrofit projects, while maintaining full overspeed protection functionality within a single module.
Lifetime Support
SpeedSys 300 delivers a clean architectural separation between control and trip logic ensuring uncompromised protection compared to integrated systems.
SIL3 by Design
Adapt as needed: from single-channel setups to fully redundant 2oo3 architectures, SpeedSys 300 supports stepwise scalability at every stage.
Compact Footprint and Seamless Integration
Engineered for space-limited panels and demanding environments, it’s ideal for both retrofits and new installations.
FAQ
Yes, it’s an independent overspeed protection system, aligned with the requirement that overspeed protection be separate from the control system.
Yes, both systems support 2oo3 redundant architectures, but they implement this redundancy in different ways. SpeedSys® 300 supports up to 2oo3 architectures through external hardwired voting, where multiple independent SpeedSys units are combined to form the required voting logic without relying on a central backplane or CPU. This allows flexible deployment of redundancy tailored to the application. HIMA HIMax X‑MIO 7/6 also supports 2oo3 evaluation, but this is implemented internally within the HIMax safety platform by using three independent speed sensors and performing 2oo3 evaluation inside the module and the associated safety processor system, as part of a rack‑based safety architecture.
Only the HIMA HIMax X‑MIO 7/6 supports Profibus‑based DCS integration, as it operates within the HIMax safety platform, which provides Profibus DP communication for integration with distributed control systems. SpeedSys® 300 does not support Profibus; its communication interface is limited to Modbus RTU over RS‑485, as specified in the available documentation.
Istec ensures the availability and safety of your rotating machinery by providing the most convenient and accessible hardware solutions, delivered by the world’s leading vibration and speed sensing experts.
Accuracy disclaimer
All of our comparison pages have been filled in to the best of our knowledge, using publicly available sources. However, we cannot guarantee that they are fully up-to-date or completely correct.
| Aspect | HIMax X‑MIO 7/6 | Istec SpeedSys 300 |
|---|---|---|
| Key features | Overspeed and acceleration monitoring; internal 2oo3 evaluation; SIL 3 certified; designed for API 670 turbine applications [a929d3 | PDF], [X-MIO 76 01 | PDF] | Overspeed, underspeed and acceleration detection; compact standalone design; modular redundancy; Modbus diagnostics |
| Number of relays | 5 safety‑related digital outputs + 1 auxiliary relay output | 2 safety relays per module plus additional signal outputs |
| Frequency range | 0 – 35 kHz | 0.0025 Hz – 35 kHz |
| Hardware response time | < 20 ms | < 8 ms |
| Number of inputs (active) | 3 safety‑related measuring inputs (2oo3 evaluation) | 1 input per module (one active sensor input at a time) |
| Voting system | Internal 2oo3 evaluation using three measuring inputs | 1oo1 (single module); 1oo2 or 2oo3 using multiple modules (external voting) |
| Outputs | 5 × safety‑related digital outputs (up to 2 A per channel, 12 A total) • 1 × non‑safety relay output (alarm) | • 1 × safety‑rated 4–20 mA analog output • 1 × binary output • 1 × frequency output • Modbus RTU (RS‑485, diagnostics only) |
| Input voltage | 24 VDC (‑15 % / +20 %, SELV/PELV) | 24 VDC (18 – 36 VDC), dual-redundant power supply |
| Functional safety | Certified up to SIL 3 according to IEC 61508 / IEC 61511 | SIL 2 / SIL 3 capable depending on redundancy configuration |
| Stand‑alone protection | Trip logic is independent of the HIMax CPU, but module operates within the HIMax PES system | Yes – each module performs a complete overspeed protection function independently |
| Relay information | 1 auxiliary relay (changeover, non‑safety‑related); 5…30 V, 1…180 mA | 2 × safety relays (DPST); max. 30 VDC / 2 A (resistive) |
| Rack / backplane mounting | Yes – mounted on HIMax baseplate with connector boards [X-MIO 76 01 | PDF] | Optional 19‑inch rack for mechanical mounting only; no shared backplane or internal bus. |
| Reserve scalability | Redundancy achieved using dual or triple connector boards within HIMax system | Scales from single module (SIL 2) to redundant multi‑module SIL 3 architectures |