Product Overview

The Yokogawa AAP135-S50 is a precision-engineered Pulse Input Module designed for the CENTUM VP Distributed Control System (DCS). This module is specialized for capturing and processing pulse train signals from field devices such as flowmeters, tachometers, and displacement sensors. By converting high-frequency pulse sequences into digital count values or frequency data, the AAP135-S50 enables accurate monitoring of cumulative totals and instantaneous rates in industrial processes.

While many standard modules focus on simple analog data, the AAP135-S50 is optimized for high-speed signal integrity. It provides robust electrical isolation between the field instrumentation and the system backplane, ensuring that transients or noise from the field do not interfere with the Field Control Station (FCS) logic. Its hardware architecture is built to withstand rigorous industrial conditions, offering long-term stability in power generation, chemical processing, and water treatment facilities.

Technical Specifications

• Manufacturer: Yokogawa Electric Corporation

• Model Code: AAP135-S50

• Module Type: Pulse Input Module

• Number of Channels: 8-channel (Isolated)

• Input Signal Type: Contact or voltage pulses (dry/wet)

• Frequency Range: Supports low to high-frequency pulse inputs (up to 10 kHz)

• Accuracy: ±0.1% or better depending on frequency range

• Redundancy: Supports dual-redundant configuration for high-availability systems

• Current Consumption: 450 mA or less (at 5V DC)

• Weight: 0.32 kg

• Dimensions: 32 x 106 x 130 mm

• Operating Temperature: -20 to 60°C

Key Functional Characteristics

High-Speed Signal Acquisition

The AAP135-S50 is capable of handling rapid pulse streams, making it ideal for turbine meters and high-speed rotary equipment. The module accurately counts pulses and calculates frequencies, which are then mapped to the I/O image area for immediate access by the DCS function blocks.

Superior Noise Immunity and Isolation

Each of the channels features dedicated isolation barriers. This prevents the formation of ground loops and ensures that electromagnetic interference (EMI) typical in motor-heavy industrial environments does not compromise the accuracy of the signal. This is critical for maintaining precise mass balance and flow measurements.

System Integration and Redundancy

Fully compatible with the CENTUM VP RIO (Remote I/O) bus, the AAP135-S50 can be deployed in a redundant pair. In this setup, if the primary module detects a hardware failure, the secondary module takes over signal processing without data loss, ensuring the continuity of safety-critical measurements.

Flexible Field Interfacing

The module supports various pulse types, including voltage pulses and contact closures. This versatility allows it to interface with a wide variety of third-party instruments. The hot-swappable design allows for module replacement without powering down the node unit, significantly reducing potential maintenance downtime.