RHEINTACHO FA-120354 – Rotational Speed Surveillance Module | FA Series Platform
Engineering Background
RHEINTACHO Messtechnik GmbH is a German precision instrumentation manufacturer with decades of specialization in rotational speed measurement and monitoring. The FA Series represents their industrial-grade line of speed monitors engineered for continuous process environments where overspeed or underspeed events carry significant safety and operational consequences. The FA-120354 is a compact, relay-output speed monitor designed to interface directly with inductive proximity sensors or magnetic pickups, delivering deterministic switching behavior without the latency of software-based monitoring loops.
Product Positioning
The FA-120354 is positioned as a standalone hardware safety layer for rotating machinery — motors, turbines, fans, conveyors, and centrifuges — where independent speed surveillance is required by machine safety standards (ISO 13849, IEC 62061) or process integrity requirements. It operates independently of the PLC/DCS control layer, ensuring that speed limit violations trigger protective relay action even during controller faults or communication loss.
Complete Technical Specifications
| Parameter | Value |
|---|---|
| Manufacturer | RHEINTACHO Messtechnik GmbH |
| Part Number | FA-120354 |
| Series | FA Series Speed Monitor |
| Function | Overspeed / Underspeed / Standstill Detection |
| Input Signal | Inductive proximity sensor / Magnetic pickup (NPN/PNP compatible) |
| Frequency Input Range | 0.1 Hz – 10 kHz (model-dependent) |
| Supply Voltage | 24 V DC (±20%) / 115–230 V AC (version-dependent) |
| Power Consumption | ≤ 5 W |
| Output Relay | 1 × SPDT relay, 250 V AC / 5 A |
| Response Time | ≤ 1 speed cycle + relay switching time |
| Setpoint Adjustment | Potentiometer (front panel) or teach-in function |
| Hysteresis | Adjustable (typically 5–15%) |
| Enclosure / Mounting | DIN rail mount, IP20 housing |
| Operating Temperature | -10 °C to +55 °C |
| Storage Temperature | -25 °C to +70 °C |
| Weight | Approx. 160 g |
| Certifications | CE marked; compliant with EN 60947-5-1 |
| Country of Origin | Germany |
Proven Application Environments
- Motor Protection: Overspeed shutdown for AC/DC drive systems where VFD feedback is insufficient as a sole safety measure.
- Conveyor Systems: Underspeed / belt-slip detection to prevent material spillage and mechanical damage.
- Turbine & Compressor Monitoring: Standstill verification before maintenance access; overspeed trip in steam/gas turbine auxiliary systems.
- Fan & Blower Control: Airflow-critical processes requiring confirmation of minimum rotational speed before process interlocks release.
- Centrifuge Operations: Lid-lock interlock release only after confirmed standstill — a common safety requirement in pharmaceutical and chemical plants.
- Pump Monitoring: Dry-run protection via underspeed detection when pump load drops below threshold.
Engineering Advantages
- Hardware-Independent Safety Layer: Relay output operates independently of PLC/DCS — protective action is not contingent on controller availability or software execution.
- Fast Response: Detection within one sensor pulse cycle; no averaging delay that could mask transient overspeed events.
- Universal Sensor Compatibility: Accepts NPN, PNP, and passive magnetic pickup signals — integrates with existing sensor infrastructure without additional signal conditioning.
- DIN Rail Form Factor: Compact footprint minimizes panel space; standard 35 mm DIN rail mounting simplifies installation and replacement.
- Adjustable Hysteresis: Prevents relay chatter at threshold boundaries — critical for stable operation in variable-load applications.
- Teach-In Setpoint: Eliminates manual frequency calculation; operator sets reference speed directly from running machinery.
System Architecture & Signal Flow
The FA-120354 monitors the pulse train generated by an inductive proximity sensor or magnetic pickup mounted adjacent to a toothed wheel, gear, or shaft-mounted magnet on the rotating machine. The module continuously computes instantaneous frequency from the incoming pulse stream and compares it against the configured setpoint threshold(s).
- Overspeed mode: Relay de-energizes (fail-safe) when measured frequency exceeds setpoint → triggers upstream contactor or safety relay to remove drive power.
- Underspeed / Standstill mode: Relay de-energizes when frequency drops below setpoint → signals process interlock or alarm system.
- Hysteresis band: Re-engagement requires frequency to return to setpoint ± hysteresis before relay re-energizes — prevents oscillation at threshold.
The relay output connects directly to the machine’s safety circuit, motor contactor coil, or PLC digital input — no intermediate signal conversion required.
Sourcing & Quality Verification
- Units sourced from authorized RHEINTACHO distributors and verified industrial surplus channels with documented provenance.
- Each unit undergoes incoming inspection: visual examination, label/marking verification, and functional power-on test prior to listing.
- Original manufacturer packaging preserved where available; repackaged units are clearly identified.
- Batch traceability records maintained for all stock — available upon request for regulated-industry procurement.
- Counterfeit-risk assessment performed: RHEINTACHO FA-series modules carry identifiable manufacturing markings and PCB characteristics that are verified during inspection.
Procurement Process
- Stock Status: Confirm real-time availability via product page or contact [email protected] before placing large-quantity orders.
- Lead Time: In-stock units ship within 1–3 business days. Out-of-stock sourcing lead time: 2–6 weeks depending on supply channel.
- Minimum Order: 1 unit. Volume pricing available for orders of 5+ units — request a quote.
- Documentation: Datasheet, wiring diagram, and CE declaration of conformity available upon request.
- Export Compliance: Standard industrial automation component; no ECCN/EAR99 restrictions anticipated. Buyer responsible for import compliance in destination country.
- Payment: T/T bank transfer, PayPal, and major credit cards accepted. Net-30 terms available for qualified corporate accounts.
Technical FAQ
Q: Can the FA-120354 be used with an encoder instead of a proximity sensor?
A: Yes, provided the encoder output is compatible with the module’s input voltage and frequency range. Open-collector or push-pull encoder outputs are typically compatible; verify signal levels against the datasheet before wiring.
Q: What happens if the sensor signal is lost (wire break)?
A: Loss of input signal is interpreted as zero frequency (standstill). In overspeed monitor mode, the relay remains energized (no trip). In underspeed/standstill mode, the relay de-energizes — triggering the protective action. This fail-safe behavior should be factored into the safety function design.
Q: Is the FA-120354 suitable for SIL-rated safety functions?
A: The FA-120354 is a standard industrial speed monitor, not a certified SIL/PLd safety device. For SIL 2 / PLd applications, a certified safety relay module (e.g., PILZ, Sick, or RHEINTACHO’s certified variants) must be used. The FA-120354 is appropriate for operational monitoring and non-safety-rated protective functions.
Q: Can I set both overspeed and underspeed thresholds simultaneously?
A: This depends on the specific firmware/hardware variant of the FA-120354. Some variants support a single threshold with selectable mode (over/under); dual-window variants support both simultaneously. Confirm with the datasheet for your specific unit revision.
Q: What is the maximum cable length from sensor to module?
A: Typically up to 100 m with shielded cable for inductive proximity sensors operating at low frequencies. At higher frequencies (>1 kHz), cable capacitance may attenuate the signal — keep runs under 30 m or use a signal amplifier/repeater.
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