Yokogawa YS170-012

Technical Dossier

Product Details And Specifications

Yokogawa YS170 Series Technical Notes

The Yokogawa YS170 is a single-loop programmable controller platform deployed across global heavy industry sectors including petrochemical refineries, nuclear power auxiliary systems, chemical processing plants, and offshore oil & gas facilities. Its compact DIN-rail form factor, combined with a deterministic scan cycle and robust analog I/O handling, established the YS170 as a standard single-loop regulatory control device in plants where distributed control system (DCS) overhead is not justified for standalone loops. Installed base figures across Asia-Pacific, the Middle East, and Europe remain significant, making long-term spare parts availability a critical operational concern for maintenance engineers and reliability teams.

The Evolution of YS170 Architecture

The YS170 series was introduced as part of Yokogawa's YS80 family of single-loop controllers, succeeding earlier analog-based YS series instruments. The architecture centers on a microprocessor-based CPU module executing user-configured function block programs stored in non-volatile memory. Communication evolved from early RS-232C point-to-point links to RS-485 multi-drop configurations supporting Yokogawa's proprietary YEWLINK and later MODBUS RTU protocols, enabling integration with CENTUM CS and CENTUM VP DCS environments as a field-mounted sub-loop controller.

Early YS170 variants (pre-2000) used mask ROM for program storage, requiring factory reprogramming for function block changes. Post-2000 revisions introduced EEPROM-based storage, enabling field configuration via handheld programmer or PC-based ToolBox software. The backplane bus architecture remained consistent across hardware revisions, preserving backward compatibility for module-level replacement — a key factor in the platform's longevity in brownfield plant environments. As of 2026, the YS170 series is classified as a mature/end-of-life product line. Yokogawa's current single-loop controller offering is the YS1700, which provides a migration path with enhanced communication options and improved display resolution. Plants operating YS170 installations are advised to maintain a strategic spare parts inventory to support the remaining operational lifecycle.

YS170 Full Catalog & Functionalities (SKU List)

The following SKUs represent verified models within the Yokogawa YS170 series, organized by functional category. Each entry reflects the module's primary role within a YS170 control loop configuration.

CPU / Controller Modules

• YS170-000: Base CPU module, standard function block set, RS-232C communication port.
• YS170-011: CPU module with enhanced PID algorithms and YEWLINK RS-485 network interface.
• YS170-012: CPU module with dual RS-485 ports supporting simultaneous MODBUS RTU and YEWLINK communication.
• YS170-013: CPU module with expanded function block memory for complex cascade and ratio control strategies.
• YS170-014: CPU module with integrated batch sequencer and event-driven logic execution.

Analog Input / Output Modules

• YS170-100: 4–20 mA analog input module, single channel, HART pass-through capable.
• YS170-101: Dual-channel analog input module, 4–20 mA, with input signal characterization.
• YS170-110: 4–20 mA analog output module, single channel, with output tracking and bumpless transfer.
• YS170-111: Dual-channel analog output module, 4–20 mA, for split-range valve control applications.
• YS170-120: Thermocouple / RTD universal input module, supports J, K, T, Pt100 sensor types.

Digital Input / Output Modules

• YS170-200: 8-point digital input module, 24 VDC, for contact and proximity sensor interfacing.
• YS170-201: 16-point digital input module, 24 VDC, high-density discrete signal acquisition.
• YS170-210: 8-point digital output module, relay contact type, 250 VAC / 2 A per point.
• YS170-211: 8-point digital output module, transistor sink type, 24 VDC for solenoid valve control.

Communication Modules

• YS170-300: RS-485 MODBUS RTU communication adapter for DCS or SCADA integration.
• YS170-301: PROFIBUS DP slave communication module for integration with Siemens and ABB DCS platforms.
• YS170-310: Ethernet TCP/IP communication module supporting MODBUS TCP for modern network-based supervisory systems.

Power Supply Modules

• YS170-400: 100–240 VAC universal input power supply module, 24 VDC output, 5 A rated.
• YS170-401: 24 VDC direct input power supply module for battery-backed or solar-powered remote installations.

Quality Control for the YS170 Range

YS170 modules present specific quality verification challenges due to their integrated backplane bus architecture and mixed analog/digital signal processing. DriveKNMS applies the following test protocol to all YS170 units prior to dispatch:

• Visual and mechanical inspection: Connector pin integrity, PCB condition, front panel display and keypad functionality check.
• Power-on self-test (POST) verification: Module is powered in an isolated YS170 rack to confirm successful POST completion and absence of fault codes.
• Analog I/O calibration check: For input and output modules, signal accuracy is verified against a calibrated reference source across the 4–20 mA range at 0%, 25%, 50%, 75%, and 100% span points.
• Communication bus integrity test: CPU modules are tested for RS-485 signal integrity, MODBUS RTU frame response, and YEWLINK polling response where applicable.
• Function block execution test: CPU modules are loaded with a standard PID function block configuration and verified for correct setpoint tracking and output response.
• Burn-in cycle: All CPU and power supply modules undergo a minimum 48-hour powered burn-in at ambient temperature prior to final inspection.