Description

• Model: YS1700-100/A31
• Brand: Yokogawa Electric
• Series: YS1000 / YS1700
• Core Function: Programmable single-loop process control
• Type: Programmable Indicating Controller
• Key Specs: 100 V AC / 24 V DC common power, RS-485, Modbus / YS protocol
• Configuration: Basic type with hard manual unit
• Mounting: Indoor panel mount
• Lifecycle: Current Yokogawa product family; availability depends on configuration

Product Introduction

Yokogawa YS1700-100/A31 is a programmable indicating controller configured as the basic type with a hard manual unit, 100 V AC / 24 V DC common power, and RS-485 communication. The /A31 option supports PC-link, Modbus, YS protocol, and peer-to-peer communication, making this configuration suitable for single-loop process control and integration with established plant control networks.

Its compact panel format is one of the practical strengths. The standard body measures 144 × 72 × 250 mm and weighs about 1.6 kg, with a 137 × 68 mm panel cutout. Yokogawa also provides replacement guidance for older YS170 controllers, and RS-485 communication can be used for direct communication with systems such as CENTUM CS3000/VP.

Key Technical Specifications

Yokogawa’s current general specification confirms the /A31 communication option and the 100 V AC / 24 V DC common-power configuration. The operating guide gives the corresponding supply ranges and RS-485 terminal arrangement.

Yokogawa YS1700-100/A31

Application and Selection Notes

This configuration fits plants where a compact controller needs to handle indication, regulation, alarms, and serial communication without replacing an established panel arrangement. Typical applications include temperature, pressure, flow, and level loops in process equipment.

The /A31 option is the important procurement detail. It is not simply a communications label. Yokogawa specifies RS-485 with PC-link, Modbus, YS protocol, and peer-to-peer functions, while /A32 serves a different DCS-LCS communication role. These options should not be treated as interchangeable.

For an installed YS170 or earlier controller, the replacement guide also documents YS170-to-YS1700 conversion examples using the corresponding RS-485 option. That makes this configuration particularly relevant when maintaining older control panels without redesigning the whole loop.

Quality Inspection and Pre-Shipment Checks

1. Incoming inspection: Check the Yokogawa nameplate, complete model code, serial number, terminal condition, display, keys, housing, and packaging. Traceability documents should be checked against the purchase record.
2. Live test: Use a suitable YS1700 test setup to verify power-up, display response, keypad operation, communication startup, alarm behavior, and controller functions. Record the results in a Test Report.
3. Electrical checks: Verify supply-path continuity, grounding continuity, terminal condition, and insulation resistance where appropriate to the test procedure.
4. Configuration verification: Record communication parameters, loop settings, input/output assignments, and any stored program or engineering configuration before shipment.
5. Final QC: Photograph the identification label, place the controller in protective packaging, secure it against mechanical shock, and attach the QC Passed record.

Test photographs and available Test Reports can be provided with the shipment on request.

Technical Replacement Risks

RS-485 settings are easy to overlook. Before removal, record station address, baud rate, parity, and other communication parameters used by the existing system.

Firmware or program mismatch can cause commissioning delays. The replacement should be checked against the installed application and YSS1000 engineering environment before field installation.

Terminal wiring must be verified. The operating guide identifies dedicated RS-485 terminals for SDA, SDB, RDA, and RDB. Do not copy wiring from memory.

Power supply selection matters. This exact configuration uses the 100 V AC / 24 V DC common-power version. A 220 V AC configuration belongs to a different suffix code.

And yes, take photos before pulling the old unit. It is still one of the cheapest forms of commissioning insurance.

Purchase and Logistics Notes

For international procurement, state the complete YS1700-100/A31 configuration, not just “YS1700.” The purchase description should identify the hard manual configuration, basic type, common 100 V AC / 24 V DC supply, and /A31 RS-485 interface.

Current Yokogawa documentation remains available, including general specifications, manuals, software, and replacement information. Yokogawa also provides a product quotation system with quality inspection certificate options, while commercial suppliers may quote different stock conditions and lead times.

For export packing, protect the front display and key assembly from impact, keep the controller dry, and make sure the commercial invoice, packing list, and product label show the same complete model number.

Quick Conclusion

• YS1700-100/A31 is a programmable single-loop controller with an RS-485 communication option.
• The exact configuration uses 100 V AC / 24 V DC common power and a hard manual unit.
• /A31 supports PC-link, Modbus, YS protocol, and peer-to-peer communication.
• The standard basic unit measures 144 × 72 × 250 mm and weighs approximately 1.6 kg.
• It is a sensible replacement candidate for established YS-series installations, provided the complete suffix configuration and control program are matched.

FAQ

What is the YS1700-100/A31?

It is a Yokogawa programmable indicating controller configured with a hard manual unit, basic type construction, common 100 V AC / 24 V DC power, and RS-485 communication.

What protocols does /A31 support?

The /A31 option supports PC-link, Modbus, Yokogawa YS protocol, and peer-to-peer communication over RS-485.

Can it communicate with CENTUM CS3000?

Yokogawa’s documentation specifically states that the /A31 communication option can be used to directly communicate with CENTUM CS3000/VP under the applicable configuration.

What is the panel cutout?

For the basic type, the specified panel cutout is 137 +2 / 0 × 68 +0.7 / 0 mm.

What should be checked before ordering?

Verify the full model code, power version, communication option, input specification, control program, terminal wiring, and existing panel cutout. Do not source the controller from the base YS1700 designation alone.

Is it suitable for replacing an older YS170?

Yokogawa provides a dedicated YS170-to-YS1700 replacement guide with specific conversion examples, including RS-485 configurations. Exact replacement suitability still depends on the original suffix and application configuration.