8 Channel 4x 20mA + 4x 10V Modbus Input Module UIO-8IN-VI

The Veawe UIO-8IN-VI is a high-density 8-channel Modbus RTU remote analog input module designed for versatile data acquisition in industrial automation, process control, and SCADA systems. It features a hybrid input architecture combining four 0–20mA / 4–20mA current loop inputs (Channels 1 to 4) and four 0–10V voltage inputs (Channels 5 to 8) in a single compact 35mm DIN-rail mountable enclosure.

With 16-bit analog resolution and factory-calibrated accuracy of ±0.1% of upper range, the module delivers high-precision measurement from diverse transmitters, sensors, and field devices across an isolated RS-485 serial bus.

Input Channel Architecture & Register Specifications

The module delivers digital representations of measured signals through dedicated Modbus registers in both raw integer format and scaled floating-point engineering units:

• Channels 1 to 4 — Current Inputs (0–20mA / 4–20mA):
• Input Registers 30001–30004 report raw current as a 16-bit integer with a resolution of 0.001 mA (1 µA).
• Value mapping: 0 = 0.000 mA, 4000 = 4.000 mA, 12000 = 12.000 mA, and 20000 = 20.000 mA.

• Compatible with standard 2-wire and 3-wire 4–20mA transmitters for pressure, level, temperature, and flow.

• Channels 5 to 8 — Voltage Inputs (0–10V):

• Input Registers 30005–30008 report raw voltage as a 16-bit integer with a resolution of 0.001 V (1 mV).
• Value mapping: 0 = 0.000 V, 1000 = 1.000 V, 5000 = 5.000 V, and 10000 = 10.000 V.
• Compatible with 0–10V, 0–5V, 1–5V, and 2–10V signals, potentiometer feedback, valve positioners, and HVAC controllers.

Signal Scaling & Engineering Values

Each input channel features dedicated non-volatile Offset (40601–40608) and Gain (40621–40636, IEEE754 float) calibration registers. The module automatically converts raw inputs into real-world physical values using the scaling formula:

$$text{Engineering Value} = (text{Raw Value} + text{Offset}) times text{Gain}$$

Scaled results are published directly into IEEE754 32-bit floating-point Input Registers (30021–30036). This enables PLCs, SCADA software, and HMIs to directly read process variables in Bar, PSI, °C, %, m³/h, or RPM without requiring mathematical scaling routines in the host PLC program.

Intelligent Alarms & Diagnostics

The UIO-8IN-VI includes comprehensive on-board monitoring and diagnostic features:
– Configurable Alarm Limits: Each channel provides independent alarm threshold configuration (40661–40708) supporting 4 operating modes: disabled, outside window, inside window, min-only, or max-only.
– Live Alarm Status: Discrete Inputs 10601–10608 reflect instantaneous alarm condition states.
– Latched Alarms: Discrete Inputs 10641–10648 capture transient alarms and remain set until explicitly read by the Modbus master, ensuring no intermittent alarm goes unnoticed.
– Sensor Open / Broken Wire Detection: Discrete Inputs 10621–10628 flag disconnected sensors or open loop circuits, alerting operators to field wiring faults.
– Retentive Alarm Counters: Input Registers 30601–30608 count the number of alarm occurrences per channel and retain values through power interruptions. Coils 00601–00608 allow remote counter resetting.

Modbus RTU Communication & Autonomous Master Mode

• Isolated RS-485 Interface: Up to 3000 Vrms bus isolation and 15kV ESD protection ensure reliable communication in harsh industrial electrical environments.
• Rotary Address Switches: Two rotary switches on the top panel provide direct hardware address selection from 01 to 99. Setting address 00 enters Default Mode (19200 baud, 8N1, Slave ID 1) for hassle-free field commissioning.
• Flexible Baud Rates: Supports baud rates from 300 to 115200 with configurable parity (8N1, 8E1, 8O1, 8N2, 8E2, 8O2).
• Modbus Master Mode: When configured in Master Mode (40104 = 1), the module can autonomously write process data from AI1–AI8 to a remote Modbus slave device at a programmable poll interval, serving as a standalone signal retransmitter or gateway without an external PLC.

Mixed Industrial Applications

Housed in a rugged 110mm × 50mm × 55mm industrial enclosure suitable for 35mm DIN rail or wall mounting, the module is powered by a wide 15–24V DC power supply. It is ideal for:
– Factory automation and machine builder panels requiring both current and voltage sensor inputs.
– Water, wastewater, and chemical dosing systems combining 4–20mA flow/pressure sensors with 0–10V dosing valve actuators.
– HVAC and Building Management Systems (BMS) measuring 0–10V air quality/damper position alongside 4–20mA chilled water flow meters.
– Distributed remote telemetry and IoT edge data logging.

Configuration Software

👉 Download ModViz Configuration Tool