Monitor Equipment Status
Read switch, float and equipment status contacts from your controller. Choose a compact input model for a few points, or add relay control when the panel needs both.
Y301-200, Y301-220, Y301-440, Y301-880Compare these modelsSerial I/O Modules for Monitoring and Control
Connect field signals to your PLC or gateway over RS485 Modbus RTU. Choose Y301 for digital I/O, mixed signals and 10 A relay control on ControlLink models, or Y331 for channel-isolated millivolt, voltage, milliamp and ampere inputs.
View Serial I/O Module Documentation
- Digital I/O
- Modbus RTU
- Multi-range AI
Field applications
What Do You Need to Monitor or Control?
Describe your signals and load. Then compare the input and output combination that fits your panel.
Switch Alarms, Valves and Contactors
Use Modbus commands to operate relay contacts. Check the selected model’s contact rating and use an external contactor when the load requires it.
Y301-020, Y301-110, Y301-220, Y301-440Compare these models
Read Sensors and Control Outputs
Bring analog measurements, digital status and relay control into one module. Choose two or four analog inputs for supported voltage or current signals.
Y301-222, Y301-444Compare these models
Y301 Modbus RTU I/O Modules with 10 A Relay Outputs
Combine digital status monitoring and relay control over RS485 Modbus RTU. ControlLink relay contacts are rated at 277 VAC 10 A or 28 VDC 10 A. Y301-220, Y301-222, Y301-440 and Y301-444 have SPDT contacts; Y301-880 has normally-open contacts.
Y301-222 and Y301-444 also include analog inputs. Match contact voltage, load type, steady current and inrush current before selection. Inductive loads may need protection and an external contactor. MiniLink relay ratings differ.
Built for your control panel
One serial link, the I/O combination your panel needs
Connect over Modbus RTU
Read inputs and control relay outputs from a compatible RS485 Modbus RTU master.
Choose the I/O You Need
Pick one or two digital points, expand to eight inputs and eight relay outputs, or combine digital I/O with analog sensing.
Measure More Analog Signal Types
Y331 offers millivolt, voltage, milliamp and ampere input ranges, with input channels isolated from one another.
Add Local Control Rules
ControlLink models support local relay rules; Y301-222 and Y301-444 also support analog threshold rules.
Connect field I/O to a serial Modbus host
A Serial I/O module sits between field signals or loads and the PLC, SCADA system, or edge controller that reads and writes its registers.
Y301-222 shown as an example. Arrows show signal flow, not terminal wiring. I/O count and signal support depend on the model.
- 01
Signal and load sideConnect compatible inputs to DI or AI, and relay outputs to the selected load circuit.
- 02
Module roleThe module exposes field states and values to the host and receives relay commands; it does not replace the controller.
- 03
Host sideMatch the interface, protocol mode, baud rate, address, and register map.
Pick the I/O task, then compare channel count and electrical limits
MiniLink, ControlLink, and FlexPoint organize the Y301 range by I/O combination and project task.
MiniLink Family
Compact one- or two-channel digital I/O for status monitoring and relay control.
Best fit
- Space-constrained panels
- Simple DI or relay DO tasks
Y301-110, Y301-200, Y301-020
View MiniLink Models
ControlLink Family
Combined digital input and relay output, with analog input and local rules on selected models.
Best fit
- Monitoring and relay control in one module
- Mixed digital and analog input requirements
Y301-220, Y301-222, Y301-440, Y301-444, Y301-880
View ControlLink Models
FlexPoint Family
Dedicated DI, AI, or AO modules for higher channel counts and signal-specific expansion.
Best fit
- Six, eight, or sixteen input channels
- Four, six, or eight analog output channels
Y301-600, Y301-800, Y301-G00, Y301-006, Y301-008, Y301-00G, Y301-0004, Y301-0006, Y301-0008
View FlexPoint ModelsFeatured Y301 models
Choose Your I/O Combination
Compare eight MiniLink and ControlLink models for digital monitoring, relay control and analog sensing.
Y301-110
1 DI + 1 relay DOY301-200
2 DI
Y301-020
2 relay DO
Y301-220
2 DI + 2 relay DO
Y301-222
2 DI + 2 relay DO + 2 AIY301-440
4 DI + 4 relay DOY301-444
4 DI + 4 relay DO + 4 AI
Y301-880
8 DI + 8 relay DONeed another I/O combination? Compare all 17 Y301 models.
Wiring patterns
Match the module to the signal and load
Use these three wiring patterns to identify the right product family. Final selection still depends on signal range, load, interface, supply, and installation conditions.
MiniLink or FlexPoint DI models
Monitor switches and equipment status
- Signal
- Dry-contact or compatible wet-contact DI
- Device or load
- Switches, buttons, level contacts, and equipment status contacts
- Check before selection
- Input voltage, common wiring, isolation, and debounce by model
More Y301 I/O combinations
Need dedicated digital input, analog input or analog output? Open the complete range and compare all 17 models by I/O, power, interface and signal limits.
Compare All 17 Y301 Models
Includes 9 additional dedicated digital input, analog input and analog output models. Compare the I/O combination, then contact us to confirm model-specific limits before ordering.
3 models
MiniLink
Compact one- or two-channel digital I/O for status monitoring and relay control.
5 models
ControlLink
Combined digital input and relay output, with analog input and local rules on selected models.
9 models
FlexPoint
Dedicated DI, AI, or AO modules for higher channel counts and signal-specific expansion.
Open detailed comparison
| Model | I/O | Power | Interface / protocol | Signal or load boundary | Best for | Action |
|---|---|---|---|---|---|---|
| Y301-110 | 1 DI + 1 relay DO | 5–36 VDC | RS485; optional RS232 / TTL, Modbus RTU | Normally-open relay, 125 VAC 0.5 A / 30 VDC 2 A | One status input and one relay-control point | |
| Y301-200 | 2 DI | 5–36 VDC | RS485; optional RS232 / TTL, Modbus RTU | Dry / wet contact, 5–36 V wet-contact, opto-isolated | Two-channel status monitoring | |
| Y301-020 | 2 relay DO | 5–36 VDC | RS485; optional RS232 / TTL, Modbus RTU | Normally-open relays, 125 VAC 0.5 A / 30 VDC 2 A | Two relay-control points | |
| Y301-220 | 2 DI + 2 relay DO | 5–36 VDC | RS485; optional RS232 / TTL, Modbus RTU | 277 VAC 10 A / 28 VDC 10 A relays, up to 4 local rules | Compact monitoring and relay control | |
| Y301-222 | 2 DI + 2 relay DO + 2 AI | 5–36 VDC | RS485; optional RS232 / TTL, Modbus RTU | 277 VAC 10 A / 28 VDC 10 A relays, 0–10 V / 4–20 mA AI selected when ordering, up to 4 rules | Mixed digital and sensor monitoring | |
| Y301-440 | 4 DI + 4 relay DO | 5–36 VDC | RS485; optional RS232 / TTL, Modbus RTU | 277 VAC 10 A / 28 VDC 10 A relays, up to 8 local rules | Four-point monitoring and control | |
| Y301-444 | 4 DI + 4 relay DO + 4 AI | 5–36 VDC | RS485; optional RS232 / TTL, Modbus RTU | 277 VAC 10 A / 28 VDC 10 A relays, 0–10 V / 4–20 mA AI selected when ordering, up to 8 rules | Mixed four-channel monitoring and control | |
| Y301-880 | 8 DI + 8 relay DO | 5–36 VDC | RS485; optional RS232 / TTL, Modbus RTU | 277 VAC 10 A / 28 VDC 10 A relays, up to 16 local rules | Higher-density digital monitoring and control | |
| Y301-600 | 6 DI | 7–30 VDC | RS485 / RS232, Modbus RTU / ASCII | Opto-isolated DI, 3.3–24 VDC active input | Six digital status points | |
| Y301-800 | 8 DI | 7–30 VDC | RS485 / RS232, Modbus RTU / ASCII | Opto-isolated DI, 3.3–24 VDC active input | Eight digital status points | |
| Y301-G00 | 16 DI | 7–30 VDC | RS485 / RS232, Modbus RTU / ASCII | Opto-isolated DI, 3.3–24 VDC active input | Sixteen digital status points | |
| Y301-006 | 6 AI | 7–30 VDC | RS485 / RS232, Modbus RTU / ASCII | 0–10 V / 4–20 mA, 12-bit, ±0.5% FS | Six analog measurement points | |
| Y301-008 | 8 AI | 7–30 VDC | RS485 / RS232, Modbus RTU / ASCII | 0–10 V / 4–20 mA, 12-bit, ±0.5% FS | Eight analog measurement points | |
| Y301-00G | 16 AI | 7–30 VDC | RS485 / RS232, Modbus RTU / ASCII | 0–10 V / 4–20 mA, 12-bit, ±0.5% FS | Sixteen analog measurement points | |
| Y301-0004 | 4 AO | 12–30 VDC | Isolated RS485; optional RS232, RTU / ASCII | 0–10 V / 4–20 mA, 14-bit, ±0.1% FS | Four analog setpoint outputs | |
| Y301-0006 | 6 AO | 12–30 VDC | Isolated RS485; optional RS232, RTU / ASCII | 0–10 V / 4–20 mA, 14-bit, ±0.1% FS | Six analog setpoint outputs | |
| Y301-0008 | 8 AO | 12–30 VDC | Isolated RS485; optional RS232, RTU / ASCII | 0–10 V / 4–20 mA, 14-bit, ±0.1% FS | Eight analog setpoint outputs |
Need help choosing? Tell us your application.
Look beyond the channel count
The correct model depends on the signal, electrical load, host connection, power, environment, and local-control requirement.
- 01
Signal direction and type
Identify each DI, relay DO, AI, or AO point and whether the signal is digital, voltage, or current.
- 02
Channel count
Count the required channels and allow for planned expansion.
- 03
Range or load
Verify analog range or relay operating voltage, steady current, inrush current, and load type.
- 04
Host interface and protocol
Check RS485, RS232, or TTL availability and the required Modbus mode for the selected model.
- 05
Power and environment
Note supply voltage, temperature, humidity, enclosure, wiring, and installation clearance.
- 06
Local rules and accessories
Confirm whether local rules, retention, converters, termination, protection, or external contactors are required.
Configure and Check I/O with YenGear Toolbox
Connect a compatible I/O module to your Windows computer through a serial adapter. Use Configuration Tool to change device settings, read inputs, operate supported outputs and set local rules.
Available settings and rule modes depend on the model and firmware. Read changes back and check the connected equipment when testing an output.
Explore YenGear Toolbox
Wiring, Setup and Documentation
Check signal limits, terminal wiring and Modbus registers for the selected model before final design or ordering.
FAQ
Questions that change model selection. Check the product family, signal type, communication option, load, and required documents before final selection.
Which Modbus RTU I/O modules have 10 A relay outputs?
Y301-220, Y301-222, Y301-440, Y301-444 and Y301-880 provide RS485 Modbus RTU and relay contacts rated at 277 VAC 10 A or 28 VDC 10 A. Y301-880 has normally-open contacts; the other four models have SPDT contacts. The rating does not apply to every Y301 model. Verify load type, inrush current and protection requirements; an external contactor may be needed.
Can Y331 measure different analog signal types on isolated channels?
Y331-0020/0040/0060/0080 offers millivolt, voltage, milliamp and ampere input range options. Each input channel is isolated from the other input channels. Choose the range when ordering and use the corresponding voltage or current terminals. Mixed ranges and switching between ranges require confirmation for the ordered configuration. The 0–10 A range measures DC current; these models have no relay outputs.
How do I choose between Y301 and Y331 Serial I/O modules?
Choose Y301 for digital inputs, relay control, mixed I/O or dedicated DI, AI and AO expansion. Choose Y331-0020/0040/0060/0080 for 2, 4, 6 or 8 isolated analog inputs with millivolt, voltage, milliamp or ampere range options. Compare the signal range and electrical limits before choosing the channel count.
How do I choose between DI, DO, AI, and AO models?
Use DI for discrete status signals, relay DO for on/off load control, AI for supported voltage or current measurements, and AO for supported voltage or current setpoints. Verify signal range, common wiring, isolation, accuracy, and load requirements in the selected model specification.
Which serial interfaces and Modbus modes are available?
RS485 Modbus RTU is available across the documented Y301 family and is the default interface for these Y331 analog input models. Y331 also offers RS232 or isolated CAN interface options; specify the interface when ordering. RS232, TTL, and Modbus ASCII are available only on selected models. Set the host interface, protocol mode, baud rate, address, and register map for the selected model.
Can relay outputs switch pumps, motors, or other inductive loads directly?
Do not select a relay from steady current alone. Check operating voltage, inrush current, switching frequency, and load type. Y301-110 and Y301-020 are rated at 125 VAC 0.5 A or 30 VDC 2 A. The featured ControlLink models are rated at 277 VAC 10 A or 28 VDC 10 A. Inductive loads may require protection and an external contactor.
Can I program my own control logic?
Selected Y301 models provide configurable local rules, such as input-to-relay actions or analog threshold control. Available rule modes and counts depend on the model and firmware. Configuring these rules does not mean the module supports arbitrary user programs or replaces a PLC. Send the required sequence and fault behavior so we can check standard rules or review customization.
Can I count sensor pulses and keep the count after power loss?
DI models can count compatible pulses, subject to their input requirements, pulse timing and debounce settings. Y301-200 retains accumulated counts after power loss. Do not assume Y301-110 has the same retention behavior; check the supplied firmware and any customization requirements. Converting a rain-gauge count to rainfall also requires its resolution in mm per pulse.
Can you customize registers or data calculations?
We can review firmware changes such as an additional counter or a calculated measurement. Send the current model and firmware, required registers, calculation, reset and power-loss behavior, and expected order quantity. Feasibility, minimum order quantity, development cost and validation are confirmed for the requested scope before ordering.
Can I connect these modules directly to Ethernet or Modbus TCP?
These serial I/O modules need a compatible external gateway to reach an Ethernet or Modbus TCP host. Select the gateway for the module’s serial interface and protocol, then confirm register mapping, polling timing and required control behavior. For a cloud connection, also confirm the gateway uplink and application data format.
What information is needed for a model recommendation?
Share the I/O type and channel count, signal range or load, host interface and protocol, supply voltage, installation environment, and any local rule requirement. Submit the conditions you know; missing details can be filled in later.
Where can I find wiring diagrams, register maps, and manuals?
Open the detailed comparison above and follow the selected model specification for electrical and mechanical limits. Use the linked technical reference for wiring, configuration, communication settings, and register information.
Do you offer analog output or higher input-count models?
Yes. Open the full model comparison for dedicated 6-, 8-, or 16-channel digital input modules, 6-, 8-, or 16-channel analog input modules, and 4-, 6-, or 8-channel analog output modules. Their supply ranges and signal specifications differ from the featured models.
Tell Us Your Application
What do you need to monitor or control? Tell us about your signals and controller. We’ll help you choose a suitable Y301 or Y331 model — no model number needed.
- I/O type and channel count
- Signal range or controlled load
- Host interface and protocol
- Supply voltage and installation environment