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Rectangular green circuit board with terminal blocks and DB9 port

UOTEK

UOTEK UT-5518 8-Channel Opto-Isolated I/O Module RS-232/485 Modbus-RTU

SKU CH-R009-1413F

Eight opto-isolated channels accept wet or dry contact inputs up to 24 V, communicate via RS-232 or RS-485 using Modbus-RTU at up to 115200 bps, and operate from 9–30 V DC across a −40 to 85 °C range

  • 8 optically isolated inputs protect host equipment from 2500V DC transients
  • Wide 9–30V DC supply suits industrial and vehicle power systems
  • Modbus-RTU over RS-232/485 enables simple SCADA and PLC integration
  • Software-selectable baud rates up to 115200bps match legacy and modern networks
  • Operates reliably from -40°C to 85°C in harsh environments

8-Channel Opto-Isolated I/O Module

The UOTEK UT-5518 provides eight optically isolated digital input channels that accept both wet and dry contact signals up to 24 V. It communicates with a host system over RS-232 or RS-485 using the Modbus-RTU protocol, making it suitable for industrial automation, remote monitoring and data-acquisition tasks where electrical isolation is required.

Sustained Operation Across Wide Temperature Range

The module operates continuously from -40 °C to 85 °C with up to 95 % relative humidity, non-condensing, and draws a maximum of 300 mA at 9 V from a 9–30 V DC supply. A 2500 V DC isolation barrier protects the communication interface from field-side transients, so signal integrity is maintained during long-term deployment in harsh environments.

DIN-Rail Mounted Enclosure With Terminal Blocks

A compact DIN-rail housing uses screw-terminal blocks for the eight input channels, power input and the RS-232/RS-485 bus, allowing secure wiring without soldering. The address range of 1–247 and software-selectable baud rates from 1200 to 115200 bps let integrators configure multiple units on a single serial bus for scalable I/O expansion.

How it compares

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Price $41.99
Pricier than about 71% of the 121 comparable items (median $19.99).

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Specifications

No published specifications for this item yet.

Questions about this item

How much heat does the UT-5518 generate when running continuously at the maximum 300 mA draw from a 9 V DC supply?

The module draws up to 300 mA at 9 V DC, and its operating temperature range is -40 to 85 °C, so it is rated for continuous use within that envelope.

What cabling and power source must I already have to connect the UT-5518 to a Modbus-RTU network?

You need an RS-232 or RS-485 serial link, a 9–30 V DC power supply, and wiring for up to eight 0–24 V opto-isolated wet or dry contact inputs.

Will the UT-5518 communicate with an older PLC that only supports 9600 baud and Modbus addresses up to 247?

Yes, the module supports 9600 baud among its selectable rates and an address range of 1–247, matching the PLC's capabilities.

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