Industrial 4-Channel RS485 I/O Module (Modbus RTU)

The Valtoris 4-Channel RS485 I/O Module (4CH-IO-RS232/485) is engineered for legacy serial networks. This compact edge device consolidates 4 digital inputs, 2 analog inputs, and 4 relay outputs over a robust RS485 or RS232 connection. 

Part No. 4CH-IO-RS232/485
sku : IoT-RIC100
INSTANT QUOTE

Robust Serial Data Acquisition

This 4-Channel Serial I/O Node offers a simple solution for integrating field sensors and actuators into existing RS485 or RS232 networks. It monitors 4 digital inputs (DI) and 2 analog inputs (AI) at the same time and safely controls 4 relay outputs (DO) using standard Modbus RTU commands.

4-Channel Serial I/O Node Overview
Primary function of the Remote I/O Controller
Supports multiple DI/DO/AI channels

Advanced DI/DO Control Features

The module allows intelligent edge functions beyond just polling. Active DI reporting, 16-bit/32-bit DI counting and direct DI-to-DO control logic can be set up, greatly reducing the processing load on the central master PLC.

DI controls DO configuration
Special functions of multiple DI/DOs

Comprehensive Diagnostic Indicators

Front panel LEDs provide real-time visual feedback for Power, RS485 Link status, and Active data transmission, enabling quick on-site diagnostics.

Rich indicator light for diagnostics

Industrial Design & Mounting

The module is housed in a compact rugged enclosure and operates reliably in the wide temperature range of -40°C to +85°C. This includes the built-in DIN-rail buckle for easy mounting beside other control cabinet components.

Rail-Mount Support for easy installation
Product Show of the 4CH-IO-RS232/485
Outline dimensions of the controller

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Remote I/O Controller Selection Guide

ModelI/O DensityNetwork UplinkPower InputDimensions (mm)

4CH-IO-RS232/485
(CURRENT MODEL)

2 AI / 4 DI / 4 DOSerial (RS232/485)Terminal (DC 9~24V)121 × 72 × 34

4CH-IO-ETH

2 AI / 4 DI / 4 DOEthernet (TCP/IP)Terminal (DC 9~24V)121 × 72 × 34

8CH-IO-ETH

8 AI / 8 DI / 8 DOEthernet (TCP/IP)Terminal + DC Jack197 × 92 × 25

8CH-IO-WF

8 AI / 8 DI / 8 DOWi-Fi (Wireless)Terminal (DC 9~24V)197 × 92 × 25

8CH-IO-LTE

8 AI / 8 DI / 8 DO4G LTE (Cellular)Terminal + DC Jack197 × 92 × 25

Hardware & Interfaces
Serial PortRS485 interface (1200~115200 bps, default 9600 bps)
Power InputDC 9~24V (Terminal Block)
Power Consumption< 1.7W, < 70mA @ 24V DC
I/O Configuration
Digital Inputs (DI)4 Channels (Passive Dry Contact or Active Level 9V/24V)
Digital Outputs (DO)4 Channels (Relay Output: 5A@250VAC / 30VDC)
Analog Inputs (AI)2 Channels (10-bit accuracy)
AI Sub-modelsCurrent (4~20mA, 0~20mA), Voltage (0~5V, 0~10V), or Resistance (0~10K)
Software & Performance
ProtocolsModbus RTU
Response Time< 30ms
Mechanical & Environment
Dimensions12.2 cm × 7.2 cm × 3.4 cm (L x W x H)
Operating Temp.-40°C ~ +85°C
⚙️ Key Hardware & Edge Capabilities
✓ Consolidated I/O Density: Monitors 4 Digital Inputs (DI), 2 Analog Inputs (AI) and controls 4 Relay Outputs (DO) simultaneously over a single RS485 bus.
✓ Native Modbus RTU: The use of standard Modbus RTU protocol makes it easy to integrate with existing PLCs, HMIs and SCADA software.
✓ High-Speed Response: High-speed relay transmission speed (response time <30ms), achieves instant control action.
✓ Flexible AI Formats: Supports a number of analog input formats, such as 4~20mA, 0~5V, 0~10V, and resistive sensors (must be confirmed before factory shipping).
✓ Ultra-Low Power Design: Highly efficient with power consumption of less than 1.7W (<70mA @ 24VDC) for low-power enclosures.

Frequently Asked Questions

Can the built-in relay outputs (DO) directly drive heavy field motors?
No. The internal relays are rated for 5A@250VAC or 5A@30VDC. They are designed for control-level switching. To drive large inductive loads like motors, you must wire these relay outputs to external, appropriately sized AC contactors or SSRs.
Can I change the Analog Input (AI) type from 4-20mA to 0-10V via software?
No. The AI input format varies depending on the specific hardware sub-model you purchase (4CH-IO-RS232/485-V5 for 0-5V, 4CH-IO-RS232/485-120 for 4-20mA, etc). “You will have to sign off the AI input form before leaving the factory.
What is the default serial port parameter for the RS485 interface?
Default serial port parameters are 9600 bps baud rate, 8 data bits, NONE parity and 1 stop bit. The baud rate can be set from 1200 bps to 115200 bps.
How fast is the relay transmission speed?
The relay transmission speed, or response time, is less than 30ms.
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