Saia PCD2.H114 Fast Counting Module

The Saia PCD2.H114 is a comprehensive fast counting module designed for integration with Saia PCD2 and PCD3 programmable logic controllers. This high-speed counter module provides four independent counting channels, enabling precise measurement of rotational speed, linear displacement, material volume, and other parameters based on pulse counting methodologies. The PCD2.H114 serves as an essential peripheral component for industrial automation systems requiring accurate detection and quantification of high-frequency pulse sequences. Communication between the PCD controller and the fast counting module is established through the I/O bus, ensuring minimal signal latency and deterministic response times for time-critical measurement applications.

High-Speed Counting Performance

The PCD2.H114 achieves counting frequencies up to 150 kilohertz per channel, providing sufficient bandwidth for high-resolution incremental encoders commonly used in motion control and positioning systems. Each of the four counter channels independently processes incoming pulse signals without sharing processing resources, guaranteeing consistent measurement accuracy across all active channels. The counting range extends from 0 to 16,777,215 counts, representing a full 24-bit resolution capability that accommodates extended measurement intervals without overflow concerns.

Incremental Encoder Interface and Quadrature Decoding

Each counter channel on the PCD2.H114 incorporates two dedicated input terminals designated as Input A and Input B, specifically designed for connecting incremental shaft encoders. The module supports quadrature decoding modes including ×1, ×2, and ×4 configurations, allowing users to optimize resolution based on encoder specifications and application requirements. In ×4 decoding mode, the module detects position changes on both rising and falling edges of both A and B input channels, effectively quadrupling the effective resolution of standard quadrature encoders. Direction detection is automatically performed based on the phase relationship between A and B input signals, enabling the module to increment counts during forward rotation and decrement counts during reverse motion when configured for bidirectional counting operation.

Configurable Input Features

Beyond the standard A and B encoder inputs, each counter channel provides a third user-configurable input designated as Input C. This flexible input terminal can be programmed to serve various functions including start value loading, preset trigger activation, gate enabling, direction selection, or interrupt generation. The module supports start value loading, allowing the counter to be initialized from a user-defined preset value rather than starting from zero on each measurement cycle. This feature is valuable in applications such as cut-to-length systems and coordinated multi-axis positioning. A trigger signal input enables recording and reading of intermediate count values without interrupting ongoing counting operations, facilitating burst measurements and in-process data capture.

Counter Controlled Output and Digital Filtering

Each channel includes a dedicated Counter Controlled Output that can be programmed to activate when the count value reaches predefined target thresholds. This CCO output serves as a real-time trigger mechanism for precise external switch operations, positioning control, or interrupt generation, operating independently of the main processor for minimal signal latency. The PCD2.H114 further incorporates user-selectable digital filters applicable to all input channels, with cutoff frequencies adjustable across a range of 10 kilohertz to 150 kilohertz. These programmable filters attenuate high-frequency noise components commonly encountered in industrial environments, improving measurement stability and counting accuracy for signals originating from electrically noisy sources. The module is programmed through the PG5 software suite, requiring firmware version 1.22.10 or higher for full functionality with PCD2 and PCD3 controllers.