YOKOGAWA YS1700-100/A06/A31 Programmable Logic Controller

The Yokogawa YS1700-100/A06/A31 is a high-performance Programmable Indicating Controller from the YS1000 series. 

It is a versatile, single-loop controller used to monitor and control process variables (like temperature, pressure, or flow) with the added capability of custom user programming for complex control logic.

1. Introduction

The YS1700 is the flagship of Yokogawa's single-loop controller line. The specific configuration -100/A06/A31 identifies it as a basic type unit equipped with a "Hard Manual" station (allowing manual control even if the CPU fails), 

an isolated two-wire transmitter input, and RS-485 communication capabilities. It features a high-visibility color TFT LCD and a dual-CPU architecture for maximum reliability.

2. Technical Parameter Table

3. Product Advantages and Features

Dual-CPU High Reliability: Uses independent CPUs for control and display. If the main control CPU fails, the display CPU allows the operator to maintain manual control of the process.

Hard Manual Override: A physical hardware circuit is built-in so that the output can be adjusted manually even if both CPUs experience a total failure.

Superior Legibility: The TFT LCD provides clear visibility even in direct sunlight, with customizable trend, bar graph, and meter displays.

Flexible Programming: Supports both text-based programming (backward compatible with YS170) and modern GUI-based Function Block programming via the YSS1000 software.

Non-volatile Memory: Uses memory that requires no battery backup, significantly reducing long-term maintenance requirements.

4. Application Cases

Boiler Control: Managing fuel-to-air ratios and water levels where a controller failure could lead to dangerous conditions.

Chemical Batching: Using custom programs to calculate complex temperature/pressure compensations in real-time.

Remote Stations: Utilizing the RS-485 (/A31) communication to send data back to a central DCS (like CENTUM VP) or a SCADA system.

Critical Pump Control: Providing a dedicated, redundant interface for high-value machinery where manual fallback is a safety requirement.

5. Other Models in the Same Series

YS1500: An indicating controller without the programmable function (multi-function mode only).

YS1310 / YS1360: Dedicated indicators with alarms or manual stations for MV setting.

YS1700-110: The version with Expandable I/O (additional digital and analog points).

YS1700-101: The 220 V AC power supply version.

Optional Codes: * /A34: Ethernet communication (Modbus/TCP) instead of RS-485.

/A02: Thermocouple direct input instead of two-wire transmitter.