Yokogawa NFAF135-S00 ProSafe-RS Frequency Input Module

Product Overview

The Yokogawa NFAF135-S00 functions as a high-precision frequency acquisition interface for the ProSafe-RS safety instrumented system. This module captures and processes frequency signals from field devices such as turbine flowmeters, speed sensors, and pulse generators. We supply this unit as 100% Brand New and Original, ensuring absolute signal integrity and compliance with rigorous safety standards for critical process monitoring.

Technical Specifications

Engineering Advantages

• Superior Galvanic Isolation: The NFAF135-S00 provides 500 V AC isolation between individual channels and between the field inputs and the system bus. This architecture prevents ground loops and protects the internal safety logic from high-voltage transients common in industrial motor control centers.

• Rapid Response Monitoring: A 10 ms data refresh cycle ensures the safety station reacts instantly to speed fluctuations or flow surges. This high-speed processing allows for the implementation of precise overspeed protection and emergency shutdown (ESD) triggers.

• Flexible Input Signal Conditioning: The module accepts both dry contact and voltage pulse inputs. Internal selectable shunt (1000 $\Omega$) and pull-up (68 k$\Omega$) resistors allow engineers to interface directly with various sensor types without requiring external signal conditioning hardware.

• Robust Noise Rejection: By utilizing a 40 $\mu$s minimum input pulse width filter, the hardware effectively ignores high-frequency electromagnetic interference (EMI). This ensures the PLC counts only legitimate process pulses, maintaining accuracy even in proximity to high-power variable frequency drives (VFDs).

FAQs

• What type of field power supply does this module require?

  The NFAF135-S00 allows you to select between 12 V DC and 24 V DC for the field power supply. Ensure your configuration matches the voltage requirements of your connected transmitters to avoid signal clipping or hardware damage.

• Can I use this module for high-speed turbine speed sensing?

  Yes. The 10 kHz input limit and 0.1% accuracy make it ideal for monitoring turbine rotation speeds. For safety-critical overspeed protection, we recommend utilizing the module within a redundant ProSafe-RS architecture.

• Does the module support MIL-standard cabling?

  Yes. The module offers two connection options: pressure clamp terminals for direct field wiring and MIL connector cables for rapid, centralized marshalling cabinet integration.

• How does the module handle signal loss?

  The ProSafe-RS system diagnostics monitor the NFAF135-S00 continuously. If a signal falls outside the 0.1 Hz to 10 kHz range or the field power supply fails, the module immediately flags a diagnostic error to the safety controller for programmed fail-safe action.