Description
Product Overview
Yokogawa YS1700-100/A06/A31 is a programmable single-loop process controller designed for industrial applications requiring accurate measurement display, PID regulation, alarm handling, and communication with supervisory systems. The unit belongs to Yokogawa’s YS1000 controller family and is designed as a replacement platform for earlier YS-series controllers while maintaining compatibility with many existing panel installations.
The Yokogawa YS1700-100/A06/A31 combines a programmable controller architecture with an isolated two-wire transmitter input and RS-485 communication interface. The /A06 input configuration allows direct connection of two-wire field transmitters commonly used for pressure, flow, level, and process measurement applications. The isolated input design helps reduce signal interference and improves measurement reliability in industrial environments.
The YS1700-100/A06/A31 is designed for both standalone operation and integration into larger automation systems. Through the /A31 RS-485 communication option, the controller can exchange data with host systems using Modbus or Yokogawa communication protocols. This makes it suitable for applications where individual process loops require local control while still being monitored from a supervisory system.
The controller provides a full-dot color LCD interface with multiple display formats including trend, bar graph, alarm, and meter views. Configuration can be performed from the front panel, while engineering tools are available for more advanced programming and parameter management.
For maintenance replacement, engineers should verify the complete model code rather than only the YS1700 base model. The suffix options determine critical functions such as input type, communication method, power configuration, and mechanical compatibility. A replacement with a different suffix may require wiring changes, parameter updates, or engineering modifications.
Technical Specifications
| Parameter | Specification |
|---|---|
| Manufacturer | Yokogawa Electric Corporation |
| Model | YS1700-100/A06/A31 |
| Product Type | Programmable Indicating Controller |
| Series | YS1700 / YS1000 Series |
| Control Type | Single-loop PID Controller |
| Power Supply | 100 VAC / 24 VDC common power |
| Input Option | /A06 Isolated two-wire transmitter input |
| Communication Option | /A31 RS-485 communication |
| Supported Protocols | PC-link, Modbus, YS protocol, Peer-to-Peer |
| Display Type | Full-dot color LCD |
| Programming Method | Function block programming / text programming |
| Mounting Type | Panel mount |
| Input Signal | 4-20 mA transmitter signals (application dependent) |
| Control Functions | PID, ON/OFF, programmable logic functions |
| Alarm Functions | Configurable process alarms |
| Communication Interface | RS-485 |
| Application Area | Process automation and industrial control |
The YS1700 ordering code defines /A06 as an isolated two-wire transmitter input and /A31 as RS-485 communication supporting PC-link, Modbus, YS protocol, and peer-to-peer communication.
YS1700-100
Main Features and Advantages
Programmable Single-Loop Control
The Yokogawa -100/A06/A31 provides a flexible platform for controlling individual process loops.
Typical control applications include:
- Temperature regulation
- Pressure control
- Flow management
- Level control
- Process equipment monitoring
The controller supports configurable PID control functions, allowing engineers to adapt operation according to process requirements.
Isolated Two-Wire Transmitter Input
The /A06 option is designed for direct connection of two-wire transmitters.
Common field devices include:
- Pressure transmitters
- Flow transmitters
- Level transmitters
- Temperature transmitters with current output
Isolation helps separate field signal circuits from internal electronics, reducing the effect of electrical noise.
RS-485 Communication Capability
The /A31 communication option allows integration with supervisory systems and control networks.
Supported communication methods include:
- Modbus RTU
- Yokogawa proprietary protocols
- PC-link communication
- Peer-to-peer communication
This allows the to operate as a local controller while providing process information to higher-level systems.
Advanced Display and Operator Interface
The color LCD provides operators with clear access to:
- Process values
- Setpoints
- Trends
- Alarm status
- Control parameters
This reduces dependence on external operator stations for routine monitoring.
Replacement Compatibility for Legacy Systems
The series was designed to support migration from previous Yokogawa controller families.
Common replacement considerations include:
- Panel cutout dimensions
- Terminal wiring
- Existing control logic
- Communication settings
- Input configuration
The base model name alone is not sufficient for replacement verification; suffix codes must match the original installation requirements.
Application Scenarios
Process Temperature Control
Used for:
- Furnaces
- Heat treatment equipment
- Ovens
- Process heaters
Pressure and Flow Regulation
Applications include:
- Pump systems
- Compressor control
- Utility systems
Chemical and Manufacturing Processes
Suitable for:
- Batch processes
- Skid systems
- Local process control panels
DCS Interface Applications
The RS-485 communication interface allows connection to supervisory systems where distributed single-loop controllers are required.
Related Components
| Model | Function |
|---|---|
| YS1500 Series | Indicating controller family |
| YS1700-100/A31 | RS-485 communication controller |
| Two-wire transmitter input with DCS-LCS communication | |
| YS020 | RS-485 termination resistor accessory |
| YS021 | 250Ω shunt resistor accessory |
Engineer’s Guide: Field Pitfalls
⚠️ Confirm the Complete Suffix Code
The family contains many variations.
Verify:
- Base model
- Power supply option
- Input option
- Communication option
- Certification option
A without /A06 may not accept the same transmitter wiring.
⚠️ Check RS-485 Network Parameters
Communication faults are often caused by:
- Incorrect baud rate
- Wrong station address
- Incorrect polarity
- Missing termination resistor
- Grounding issues
The controller hardware may be healthy even when communication fails.
⚠️ Verify Transmitter Loop Wiring
For /A06 applications inspect:
- 24V loop supply
- Current signal polarity
- Shield grounding
- Terminal connections
- Transmitter output condition
A faulty field transmitter can appear as a controller input failure.
⚠️ Preserve Existing Control Parameters
Before replacing the controller, record:
- PID tuning values
- Alarm settings
- Input scaling
- Communication parameters
- User program logic
The hardware replacement alone does not restore the original process behavior.
⚠️ Refurbished Unit Testing Requirements
A proper evaluation should include:
- Power supply test
- LCD display inspection
- Analog input simulation
- RS-485 communication test
- Output control verification
- Alarm function test
- Parameter backup verification
A simple display power-up test does not confirm controller functionality.
Frequently Asked Questions
What isawa /A06/A31?
It is a programmable indicating controller with isolated two-wire transmitter input and RS-485 communication capability.
Is /A06/A31 a PLC?
No. It is a single-loop process controller designed for local control applications.
What does /A06 mean?
/A06 indicates an isolated two-wire transmitter input option.
What does /A31 mean?
/A31 indicates RS-485 communication supporting PC-link, Modbus, YS protocol, and peer-to-peer communication.
Can it replace older Yokogawa controllers?
Yes, in many applications, but engineers must verify panel dimensions, wiring, configuration, and control program compatibility.
