Product Overview

The Yokogawa NFAF135-S00 functions as a high-precision frequency input interface for the CENTUM VP and ProSafe-RS Distributed Control Systems. This module captures pulse-train signals from field devices such as flow meters, tachometers, and speed sensors. By converting frequency-based signals (ranging from 0.1 Hz to 10 kHz) into digital data, the NFAF135-S00 enables accurate monitoring of rotational speeds and volumetric flow rates. Each of its 8 channels features independent isolation, ensuring that high-frequency electrical noise from the field does not compromise the integrity of the system backplane.

Condition: 100% Brand New Original.

Part Number Breakdown: NFAF Series

Yokogawa employs a specific coding structure to define the signal type and environmental specifications for the NFAF series.

• NFAF135: Frequency Input Module (8-channel, isolated).

• -S: Standard type for general industrial applications.

• 0: Basic configuration without specialized display/explosion protection.

• 0: Standard hardware revision for FIO system compatibility.

Technical Specifications

The NFAF135-S00 provides high-resolution frequency measurement with robust voltage protection.

Engineering Advantages

• High-Noise Environment Immunity: The module utilizes individual channel-to-channel isolation. This barrier prevents ground loops and electromagnetic interference (EMI) from distorting the frequency measurement, which is critical when monitoring high-speed turbines or pumps located near large motor drives.

• Wide Dynamic Range: Measuring from 0.1 Hz up to 10 kHz, this module handles both low-flow volumetric pulses and high-speed rotational tachometers. This versatility allows engineers to standardize on a single module type for diverse speed and flow applications.

• Configurable Field Power: The NFAF135-S00 provides internal field power (12V or 24V DC). This eliminates the need for external bulk power supplies for your sensors, simplifying the cabinet layout and reducing the total number of failure points in the loop.

• Millisecond Refresh Precision: A 10 ms data update cycle ensures that the DCS captures rapid changes in frequency instantly. This low-latency performance allows for tighter PID control in speed-critical processes and improves the accuracy of totalized flow calculations.

FAQs

Q: Can the NFAF135-S00 monitor low-speed rotation?

A: Yes. The module supports frequencies as low as 0.1 Hz. This makes it ideal for monitoring slow-moving equipment or low-flow meters where pulse intervals are significantly longer.

Q: Does this module support sinusoidal (sine wave) signals?

A: The NFAF135-S00 specifically targets rectangular voltage pulses and contact inputs. For low-level sine wave signals from magnetic pickups, you typically require a signal conditioner to square the wave before it reaches the NFAF135-S00 terminals.

Q: Is it possible to use this module for Sequence of Events (SOE) recording?

A: While the NFAF135-S00 captures pulses very quickly, it is primarily a frequency-to-data converter. For high-resolution SOE time-stamping of discrete events, Yokogawa recommends dedicated digital input modules with SOE support.

Q: How does the module handle signal bouncing from mechanical switches?

A: The module requires a minimum pulse width of 40 μs. This hardware filter, combined with digital processing, ensures that the module ignores high-frequency mechanical "chatter" and only counts valid signal transitions.