PLCs, Power Supplies & Others

Central Processing Function

This processor module acts as the primary controller for Yokogawa distributed control systems. It executes regulatory control, logic sequencing, and data acquisition with deterministic precision. You can install this unit in central control rooms or remote equipment cabinets. The CPU handles multiple PID loops and advanced control strategies simultaneously. It coordinates all I/O scanning and communication activities across the network. This processing engine supports critical applications in refining and chemical production.

Physical Dimensions and Cabinet Mounting

The Yokogawa CP345 S1 measures 250.0 mm in height and 45.0 mm in width. Its depth reaches 180.0 mm from the front bezel to the backplane connector. This unit weighs approximately 1.65 kg, requiring careful two-handed installation. You can slide this module into any standard Yokogawa chassis slot. Two ejector levers lock the unit securely in its operational position. The extruded aluminum housing provides excellent thermal dissipation and EMI shielding.

Processor Specifications and Execution Performance

This module features a 32-bit RISC processor operating at 100 MHz clock speed. It executes 1,000 ladder logic steps within a 5-millisecond scan cycle. The Yokogawa CP345 S1 handles floating-point mathematics and trigonometric functions efficiently. It supports both ladder diagram and structured text programming languages. The processor includes a hardware watchdog for automatic system reset on faults. This performance level suits fast-acting process control and batch sequencing applications.

Memory Resources and Data Retention

The module contains 4 MB of flash memory for firmware and user program storage. It also provides 2 MB of battery-backed SRAM for process variables and alarms. The Yokogawa CP345 S1 includes 128 KB of EEPROM for hardware configuration settings. You can partition the SRAM into trend logs and event history buffers. The flash memory allows firmware upgrades without hardware modification. The battery maintains all critical data during extended power interruptions.

Communication Interfaces and Protocol Support

This processor offers two RS-485 ports for connecting remote I/O nodes. It also includes one 10/100Base-T Ethernet port for plant network integration. The Yokogawa CP345 S1 provides a dedicated RS-232 port for local programming access. You can connect human-machine interface panels through the second serial channel. The Ethernet port supports Modbus TCP and Yokogawa’s proprietary protocols. These interfaces ensure seamless interoperability with existing automation infrastructure.

Internal Component Architecture

The main PCB contains a high-performance memory controller and bus arbitration logic. You will find a precision voltage reference for analog-to-digital conversion stability. The Yokogawa CP345 S1 uses a temperature-compensated crystal oscillator for timing accuracy. A dedicated DMA controller handles high-speed data transfers without CPU intervention. The board includes over 200 individual components including resistors, capacitors, and ICs. This design prioritizes reliability for 24/7 continuous operation.

Power Consumption and Backup Provisions

This processor draws 650 mA from the 5 VDC backplane supply under full load. It also consumes 160 mA from the 24 VDC field power rail. An internal 3.6 V lithium battery provides backup for the SRAM and real-time clock. This battery delivers a service life exceeding 5 years in normal operation. The module also incorporates a 0.47 F supercapacitor for temporary data retention. This supercapacitor maintains memory contents for 72 hours during battery changes.

Environmental Ratings and Operational Limits

The Yokogawa CP345 S1 operates reliably between 0°C and 60°C ambient temperature. It withstands relative humidity from 10% to 90% without condensation effects. The enclosure meets IP20 protection standards for indoor control room use. Vibration tolerance reaches 2 G from 10 Hz to 150 Hz along each axis. Shock resistance measures 15 G for 11 milliseconds half-sine pulses. These specifications make it suitable for power generation and pharmaceutical facilities.

Technical Data Summary

Diagnostic Features and Operator Interface

This module includes a front-panel LCD display for real-time status monitoring. Four pushbuttons allow you to scroll through diagnostic menus easily. The display shows CPU utilization, memory usage, and error counts. Three LED indicators provide power, run, and fault status at a glance. The module also supports remote firmware updates via the Ethernet connection.

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