520M - RS-485 Modbus RTU to 8 Isolated Digital Input/8 High Current Form C Relay Output Adapter (SeaI/O-520M)

Lifetime Warranty

This product has a lifetime warranty against product failure (excludes user or enviromental damage).


This product fully adheres to the Restriction of Hazardous Substances Directive 2002/95/EC, RoHS for short.  The directive covers the restriction of use of certain hazardous substances in electrical and electronic equipment and was adopted in February 2003 by the European Union.


CE is a mandatory standard for products on the market in the European Economic Area. By CE marking a product, the manufacturer ensures that the item meets the essential safety requirements set out in the applicable CE directive.

FCC Approved

The Federal Communications Commission (FCC) is an independent agency of the United States government that sets standards and governs the testing of conducted and radiated emissions such as EMI.

520M Output Adapter
Featured in:SeaI/O RS-485 AdaptersSealevel Serial I/O Adapters
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Expansion and Strap Kit - for SeaI/O, Relio R1100 Systems
2 in stock
SeaI/O 100-240V AC to 24V DC @ 1A, International Wall Mount Power Supply
RS-485 Interconnect Cable, 5" in Length - for SeaI/O, Relio R1100 Systems
Terminal Block Kit - RJ45 to 9 Screw Terminals
Universal Mounting Bracket (VESA) - for SeaI/O, Relio R1000 Systems
Flush Mount Bracket Kit - for SeaI/O, Relio R1000 Systems
All prices exclude VAT at current rate.
Minimum order value - £30 (exc. VAT and delivery).
Free delivery of the 520M to UK Mainland on orders over £150 (exc. VAT and delivery) when purchasing online - excludes Northern Ireland, Isle of Man, Isle of Wight, Scottish Islands and the Channel Islands.

* Lead time is indicative and is subject to change at time of ordering. Next business day delivery on in-stock products only (when ordered before 3pm).
** Contact us for quantity or project pricing.
† Additional delivery charge may be incurred for certain postcodes (calculated at checkout)
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520M overview

  • Manufacturer : Sealevel Systems
  • Interface : RS-485 Modbus RTU
  • Total Channels : 16
  • Inputs : 8 x Optically Isolated Digital Inputs
  • Input Range : 5V to 30V DC
  • Input Isolation : 300V
  • Outputs : 8 x High Current Form C Relay (SPDT) Outputs
  • Max. Contact Voltage : 60V DC, 250V AC Max
  • Max. Contact Current (AC) : 6A max
  • Max. Contact Current (DC) : 30V DC @ 5A max., >30V DC @ 500mA max.
  • Switching Capacity : 5V DC @ 100mA min.
  • Enclosure : Housed in rugged, attractive steel enclosure
  • I/O Connector : Removable screw terminals simplify field wiring
  • RS-485 Connector : Use twisted-pair wiring connected to RS-485 signals via screw terminals on left side of SeaI/O module
  • Other Features : Input power via terminal block or modular connector
  • DIN rail or table mount
  • Dimensions : W7.5" x H1.3" x D5.1"
  • Power Requirement : 9V to 30V DC @ 3.5W (TR108 24V DC PSU available)
  • Operating Temperature : 0C to +70C (extended temperature options available)
  • Software Support : SeaMAX supports Linux, Windows 2000, XP, Vista and Windows 7
  • Warranty : Lifetime Warranty
Control and monitor 8 optically isolated inputs and 8 (SPDT) high-current Form C relay outputs via a RS-485 Modbus RTU port with the SeaI/O-520M.

Inputs can range from 5-30V DC and optical isolation protects the computer and other sensitive equipment from voltage transients and ground loops that are common in industrial environments.

The high-current Form C relays can switch up to 6A loads at 250V AC and up to 5A at 60V DC. Form C relays can be wired for either normally open or normally closed operation. The SeaI/O-520M is powered from your 9-30V DC source, or select from a variety of Sealevel power supply options.

Communicate with the SeaI/O-520M using the Sealevel SeaMAX API software libraries or use any Modbus RTU compliant device. Sealevel's SeaMAX software drivers and utilities make installation and operation easy using Windows and Linux operating systems.

Expand your I/O network with SeaI/O "N" series products. SeaI/O modules are available with Reed and Form C relays, optically isolated inputs, TTL interfaces, A/D and D/A functionality. Up to 246 additional expansion modules can be added using convenient pass-through connectors.
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T: +44 (0)1782 337 800 • E: sales@impulse-embedded.co.uk
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+44(0)1782 337 800