Eletechsup industrial remote I/O modules, Modbus RTU relay boards, and OPMS buffers

Module identification and Eletechsup part number nomenclature (RS485 & I/O boards)

Eletechsup Technology (founded in 2013; operating R&D and manufacturing facilities in Guangzhou and Shenzhen, Guangdong Province, China) develops and manufactures remote I/O modules, Modbus RTU serial communication boards, optocoupler isolation amplifiers, and DC motor controllers for industrial

automation, HVAC systems, and PLC expansion.

The manufacturer part numbering system follows a systematic alphanumeric structure indicating physical interface, channel circuitry, and channel density. The R4 prefix designates onboard RS485 transceivers communicating via standard Modbus RTU protocol.

The channel code denotes output/input mechanics: D3B and D2C indicate Form-C mechanical relay outputs, IOI and IOJ represent discrete digital inputs (DI), the OPMS series covers high-speed optical isolation amplifiers and level translators, and N4 denotes sensor measurement interfaces such as 1-Wire

DS18B20 digital temperature boards. Suffix digits (04, 08, 16, 32) identify the exact count of independent hardware channels.

For accurate board identification and cross-referencing, review the silk-screened markings and component labels on the printed circuit board.

Key electrical parameters including nominal supply voltage (DC 5V, 12V, or 24V), relay contact ratings, and firmware revision are permanently silkscreened onto the top copper layer.

R4D3B16 16-channel relay boards: Modbus RTU command set and coil switching topologies

The R4D3B16 16-channel relay module provides distributed remote switching across automation networks via 2-wire RS485 communication. It allows host PLCs, industrial PCs, and SCADA packages to operate field actuators without dedicated parallel output wiring.

Each of the 16 channels features an electromechanical relay with SPDT (Form-C) contacts comprising Normally Open (NO), Normally Closed (NC), and Common (COM) screw terminals.

The internal microcontroller supports standard Modbus function codes: 01 (Read Coils), 03 (Read Holding Registers), 05 (Write Single Coil), 06 (Write Single Register), 15 (Write Multiple Coils), and 16 (Write Multiple Registers).

Operating modes include momentary jog, toggle self-locking, dual-channel interlock, and programmable turn-off delay timing from 1 to 9999 seconds.

The module is housed in an industrial plastic carrier designed for standard 35 mm DIN-rail mounting. Pluggable 5.08 mm pitch screw terminal blocks allow swift field servicing without disconnecting individual wire strands.

Power and communication lines are fortified with TVS surge diodes and auto-resetting thermal fuses.

R4IOI16 16-channel digital input boards: discrete sensor aggregation over Modbus RTU

The R4IOI16 digital input module aggregates discrete signals from industrial machine switches and transmits channel status bits over an RS485 serial bus, expanding digital input capacity for supervisory PLC systems economically.

All 16 input channels are electrically isolated through high-speed optocouplers, protecting low-voltage logic from ground loops, electrical transients, and drive switching interference.

The front-end circuitry reliably interfaces with voltage-free dry contacts, limit switches, and both NPN (sinking) and PNP (sourcing) proximity sensors.

Individual LED indicators provide real-time status monitoring for each input channel alongside dedicated power and serial activity LEDs (TX/RX). This enables technicians to troubleshoot sensor lines visually at the enclosure without external test equipment.

Modbus function code 02 (Read Discrete Inputs) reads all 16 channel states in a single query packet.

R4IOJ32 high-density 32-channel DI modules: DIP addressing and distributed acquisition

For complex material handling lines, automated storage systems, and multi-station packaging equipment, enclosure space is a critical engineering constraint.

The Eletechsup R4IOJ32 consolidates 32 digital inputs onto a single compact PCB, halving required DIN-rail footprint compared to modular 16-point slices.

An onboard 8-position DIP switch allows rapid manual assignment of Modbus slave address (IDs 1 through 63) and serial baud rate (1200, 2400, 4800, 9600, 19200, 38400, 57600, and 115200 bps) without software configuration tools, accelerating field commissioning.

The internal register map arranges the 32 input states into two consecutive 16-bit holding registers, allowing SCADA masters to poll all sensor points in a single transmission cycle with minimal serial bus overhead and rapid update latency.

OPMSA04 signal amplifiers: optical isolation and PLC logic level translation

Heterogeneous automation systems frequently require interfacing disparate voltage domains: embedded microcontroller boards operate at 3.3V or 5V logic, whereas factory PLCs and industrial sensors standardize on 12V or 24V DC.

The OPMSA04 serves as a 4-channel bidirectional optoisolator and power buffer.

Each channel features an optocoupler rated for 2500V RMS dielectric breakdown coupled to high-gain transistor output stages. The module reliably couples 3.3V/5V signals from microcontrollers or CNC motion cards to 24V inputs on industrial PLCs from Siemens, Omron, Delta, or Mitsubishi.

High-speed switching characteristics ensure distortion-free transmission of high-frequency pulses, making the OPMSA04 suitable for optoisolating stepper motor step/direction clock trains, rotary encoder quadrature channels, and pulse-width modulated (PWM) control signals.

OPMSB08 8-channel level converters and current buffers: circuit protection and PWM drive

The OPMSB08 provides 8 independent channels of level shifting and current amplification on a compact DIN carrier, designed to drive intermediate pilot relays, warning light stacks, and miniature pneumatic solenoid valves directly from low-power controller outputs.

Dual power-rail topology isolates the sensitive controller power supply from actuator switching currents. Integrated flyback diodes suppress reverse inductive voltage spikes, preventing driver transistor puncture and eliminating electrical noise injection across DC supply rails.

Low saturation voltage and minimal thermal dissipation allow continuous operation at full rated load without forced-air cooling, permitting high-density side-by-side DIN rail mounting inside sealed IP65 control enclosures.

OPMSD16 solid-state MOSFET switching boards: arc-free solenoid and valve actuation

High-cycle automated equipment, including pneumatic sorting valves, filling machines, and dust collector pulsing solenoids, quickly wears out electromechanical relay contacts. The 16-channel OPMSD16 module replaces mechanical relays with solid-state power MOSFETs.

With ultra-low on-state resistance Rds(on), each channel switches up to 5A continuous at voltages up to 30V DC without contact arcing, bouncing, or acoustic noise. Solid-state switching delivers an unlimited mechanical operational lifespan under continuous 24/7 industrial duty cycles.

All channels are optically isolated from input drive circuits, equipped with status LEDs, and wired via heavy-duty screw terminals accommodating industrial wires up to 2.5 mm² cross-section, ideal for upgrading legacy relay panels.

N4DSB03 temperature sensor acquisition adapters and reversible DC motor drive modules

Eletechsup manufactures specialized sensor acquisition hardware including the N4DSB03 digital temperature converter.

The device queries Dallas DS18B20 digital probes across a 1-Wire multi-drop bus, translating temperatures into standard 16-bit Modbus RTU holding registers over RS485 up to 1200 meters. The measurement range spans -55°C to +125°C with ±0.5°C factory calibrated accuracy.

For automated dampers and positioning stages, Eletechsup offers reversible DC motor controllers for 12V and 24V brushed motors.

These units integrate forward/reverse switching with programmable reversal deadtime delays and dedicated hardware limit switch inputs, cutting motor power immediately upon stroke completion while preserving reverse travel capability.

We supply authentic Eletechsup remote I/O modules, serial communication boards, and control hardware to industrial automation integrators and machine builders worldwide with comprehensive electrical documentation and global dispatch.