Emerson AMS 6300 Sis vs Istec 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.
AMS 6300 Sis
Istec SpeedSys 300
Proven-in-use
The AMS 6300 SIS is designed for use in critical turbomachinery applications and has an established operational history in compressor and turbine protection systems. The system is typically applied where continuous operation, online testing, and long‑term maintainability are key requirements.
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 optional acceleration) protection is implemented within a single, rack‑based system architecture, combining sensing, internal voting, and trip functions at system level via a dedicated backplane.
Standalone protection concept
Integrated redundancy approach
Redundancy is implemented within the system using multiple single‑channel measurement cards and internal 2oo3 trip voting provided by the backplane.
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
Safety‑related shutdown and alarm outputs are provided at system level. Detailed relay specifications are not specified in the available datasheet.
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 installation
The AMS 6300 SIS is installed as a rack‑mounted system with multiple modules integrated into a shared backplane, allowing centralized system maintenance and configuration.
Compact and practical design
The compact footprint supports space‑constrained installations and retrofit projects, while maintaining full overspeed protection functionality within a single module.
Communication for diagnostics
Serial communication interfaces (RS‑232, RS‑422, RS‑485) using Modbus are available for diagnostics, monitoring, and system integration.
Communication for diagnostics
Modbus RTU over RS‑485 is provided for monitoring and diagnostics, without making communication part of the safety function.
System‑level protection architecture
Overspeed protection functionality is implemented at system level and depends on the combined operation of measurement cards and backplane; independent module‑level protection is not specified in the available documentation.
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.
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. The Istec SpeedSys® 300 supports 2oo3 by using multiple independent SpeedSys modules that are externally hardwired together to create the voting logic, allowing flexible implementation of redundant architectures. The Emerson AMS 6300 SIS also supports 2oo3 redundancy, but this is achieved through an internal voted backplane, which requires three separate speed monitor modules to enable 2oo3 voting within the system architecture.
Only the Emerson AMS 6300 SIS supports Profibus‑based DCS integration. Emerson offers Profibus DP (V0) as an optional communication interface on specific AMS 6300 SIS monitor variants, enabling direct integration with Profibus‑based control and safety systems. The Istec SpeedSys® 300 does not support Profibus; its digital communication is limited to Modbus RTU over RS‑485, as specified in the available documentation.
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.
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.
| Aspect | Emerson AMS 6300 Sis | Istec SpeedSys® 300 |
|---|---|---|
| Key features | Overspeed protection; TÜV‑certified SIL 3 system; integrated 2oo3 voting; integrated proof testing; API 670 compliant | Overspeed, underspeed and acceleration detection; modular redundancy; safety relays and safety analog output per module; Modbus diagnostics |
| Number of relays | Trip‑voted system: 2 × 2oo3 trip relays, 2 × function relays, 1 × Channel OK relay Trip‑not‑voted system: 3 trip relays, 2 function relays | 1 input per module (only one sensor input active at a time) |
| Frequency range | 0 – 20 kHz | 0.0025 Hz to 35,000 kHz |
| Hardware response time | ≤ 20 ms (depending on measurement mode) | < 8 ms |
| Number of inputs (active) | Up to 3 inputs per system (3 × single‑channel speed monitors) | • 1 × safety‑rated 4–20 mA analog output • 1 × binary output (open collector) • 1 × frequency output • Modbus RTU (RS‑485, diagnostics only) |
| Voting system | Internal 2oo3 voting via backplane using three speed monitors | 1oo1 (single module); 1oo2 or 2oo3 using multiple modules (external voting) |
| Outputs | Channel OK output • • 2 × analog current outputs (0–20 mA / 4–20 mA) per monitor • 6 × digital / function outputs per monitor • 3 × pulse outputs per monitor | 2 safety relays per module plus additional signal outputs |
| Input voltage | 24 VDC (19 – 31.2 VDC), redundant supply possible | 24 VDC (18 – 36 VDC), dual-redundant power supply |
| Functional safety | SIL 3 for overspeed protection; SIL 2 for protection against wrong rotational direction | SIL 2 / SIL 3 capable; functional safety embedded in system design |
| Stand‑alone protection | Not specified at module level; protection implemented at system level | Yes – each module performs a complete overspeed protection function independently |
| Relay information | SPDT relay contacts; max. 48 VAC / 4 A or 30 VDC / 4 A | 2 × safety relays (DPST); max. 30 VDC / 2 A (resistive load) |
| Rack / backplane mounting | Yes – rack‑mounted system with shared backplane | Optional 19‑inch rack for mechanical mounting only; no shared backplane or internal bus. |
| Reserve scalability | Scalability within rack‑based architecture using additional speed monitors | Scalable from single module (SIL 2) to redundant multi‑module SIL 3 configurations |