Product Overview
Yokogawa AAP135-S50/K4A00 Pulse Input Module
AAP135-S50/K4A00
The Yokogawa AAP135-S50/K4A00 is an 8-channel channel-isolated pulse input module engineered for high-precision pulse counting and flow signal processing in CENTUM DCS systems. Supporting pulse input frequencies up to 10 kHz, built-in channel-to-channel isolation, and dual-redundant options, it ensures dependable data collection across critical automated operations.
High-Precision Pulse Signal Processing for Field Flow Instrumentation
The Yokogawa AAP135-S50/K4A00 Pulse Input Module is a specialized field I/O (FIO) module designed to process high-speed pulse inputs within distributed control system (DCS) architectures. Featuring 8 channel-isolated pulse input channels, the module converts raw pulse counts and frequency signals—originating from turbine flow meters, positive displacement meters, optical encoders, and rotating speed sensors—into precise digital totalization and flow rate values. Capable of handling pulse frequencies from 0 to 10 kHz with a minimum pulse width requirement of 40 µs, it ensures complete accuracy in dynamic fluid metering and motion control loops.
Comprehensive Channel Isolation & Field Compatibility
Electrical interference and ground potential variations in industrial environments can corrupt measurement data or damage sensitive control processors. The AAP135-S50/K4A00 provides 500V AC galvanic isolation both between input channels and between field wiring and system electronics. Each channel is individually configurable to support multiple pulse signal types, including dry contact switches, transistor open-collector inputs, voltage pulses (3 to 24 V DC), and current pulses. Additionally, the module can supply loop power to 2-wire field transmitters, eliminating the need for external auxiliary power supplies in distant field junctions.
System Availability & Redundant Deployment Support
Continuous process infrastructure demands continuous module operation without measurement interruption during maintenance. The AAP135-S50/K4A00 is designed to support dual-redundant module pairing. When installed in redundant slots, two modules execute high-availability synchronization, ensuring automatic failover without missing pulse counts during a hardware fault. Paired with the /K4A00 connection specification for seamless field terminal integration, this module delivers robust performance across chemical processing, refining, utility management, and power generation environments.
Key Applications
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Flow Measurement & Totalization: Accurate pulse counting from turbine, vortex, and positive displacement flowmeters in custody transfer and fluid processing.
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Rotating Machinery Monitoring: Real-time pulse frequency acquisition from tachometers and proximity sensors on pumps, turbines, and compressors.
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Chemical & Dosing Control: Precision batching totalization and liquid metering across continuous chemical dosing lines.
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Water & Utilities Infrastructure: Multi-channel flow metering and volume tracking across municipal water distribution and treatment facilities.
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Energy Management Systems: High-density pulse collection from electric meters and utility flow transmitters across industrial facilities.
Technical Specifications
| Parameter | Specification Details |
| Model Code | AAP135-S50/K4A00 |
| Module Type | Pulse Input Module (for FIO) |
| Number of Channels | 8 channels, isolated between channels and system |
| Input Signal Types | Dry contact ON/OFF, Voltage pulse, Current pulse |
| Input Frequency Range | 0 to 10 kHz |
| Minimum Pulse Width | 40 µs |
| Isolation Voltage | 500 V AC for 1 minute (channel-to-system and channel-to-channel) |
| High Input Level (VH) | 3.0 to 24.0 V DC |
| Low Input Level (VL) | -1.0 to 8.0 V DC |
| Contact Capacity | 12 V DC / 15 mA or higher; 24 V DC / 30 mA or higher |
| Transmitter Power Supply | Integrated power supply capability for 2-wire field devices |
| Redundancy Support | Supports dual-redundant configuration |
| Power Consumption | Approx. 350 mA (5 V DC), 450 mA (24 V DC) |
| Weight | Approx. 0.3 kg |
FAQ
Q1: What type of field pulse signals does the Yokogawa AAP135-S50 module accept?
A: The module accepts dry contact ON/OFF signals, voltage pulses (3 to 24 V DC), and current pulses from 2-wire or 3-wire pulse transmitters.
Q2: Does the AAP135-S50/K4A00 provide channel-to-channel isolation?
A: Yes, it features full 500V AC isolation between individual input channels as well as between the field inputs and system logic.
Q3: What is the maximum pulse input frequency supported by this module?
A: The AAP135 pulse input module supports frequencies from 0 to 10 kHz with a minimum pulse width requirement of 40 µs.
Q4: Can this module be installed in a dual-redundant configuration?
A: Yes, two AAP135 modules can be configured as a dual-redundant pair in the DCS rack to ensure continuous signal counting without data loss.
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