The Novus DigiRail Connect DMIX 8DI / 4 Relay (8811612440) adds 8 digital inputs and 4 relay outputs to almost any PLC, SCADA or data logging system, over Ethernet (Modbus TCP) or RS485 (Modbus RTU). The relays give volt-free contacts for switching contactor coils, alarms, valves and other AC or DC loads up to 250Vac, while the inputs accept PNP, NPN or dry contact signals and can be configured as pulse counters.
Every DigiRail Connect model has Ethernet, RS485 and Micro USB on board. It works as a Modbus RTU slave on an existing RS485 network or as a Modbus TCP server on Ethernet, and can act as a transparent Modbus TCP to RTU gateway, so an Ethernet PLC or SCADA system can read RS485 instruments wired to its terminals with no register mapping. Configuration and I/O testing use free Novus NXperience software over USB.
Lead time: made to order by Novus, typically 1–2 weeks to dispatch.
DigiRail Connect Range
All four DigiRail Connect models share the same Ethernet/RS485 hardware and software. Choose by the I/O mix you need:
- DMIX 8DI / 8DO (8811612420) — 8 digital inputs, 8 PNP transistor outputs
- DMIX 8DI / 4 Relay (8811612440) — this model: 8 digital inputs, 4 relay outputs
- RAMIX 2AI / 2AO / 4DI / 3DO (8811611420) — 2 universal analogue inputs, 2 analogue outputs, 4 digital inputs, 3 PNP outputs
- RAMIX 2AI / 2AO / 4DI / 2 Relay (8811611440) — as above with 2 relay outputs
Only need analogue inputs on RS485? The lower-cost Novus DigiRail-2A converts two thermocouple, Pt100, mV, V or mA signals to Modbus RTU.
✅ 3 Year Manufacturer Warranty — backed by our UK-based technical support
Novus DigiRail Connect Datasheet Download
Novus DigiRail Connect Manual Download
Technical Details
Order code: 8811612440 (DigiRail Connect DMIX 8DI / 4RL ETH)
Digital inputs: 8, PNP, NPN or dry contact, configurable counter function
Relay outputs: 4, switching voltage up to 250Vac, resistive loads (see manual for per-channel current rating)
Communication: Ethernet 10/100 Mb/s (IEEE 802.3u), RS485, Micro USB
Protocols: Modbus TCP server, Modbus RTU slave, transparent Modbus TCP to RTU gateway
Configuration software: Novus NXperience (free, via USB)
Power supply: 10-36 Vdc, 5W max (20mA typical)
Operating conditions: -20 to 60°C, 5-95% RH non-condensing
Enclosure: ABS+PC, 35mm DIN rail mounting
Frequently Asked Questions
Should I choose this relay model or the DMIX 8DI / 8DO?
Choose this model when you need volt-free contacts or want to switch AC loads directly. The 8DO model has more outputs and PNP transistor switching, which suits PLC-level DC signals and fast pulsing.
Can the relays switch a motor or heater directly?
The relays are rated for resistive loads at up to 250Vac. For motors, heaters or large inductive loads, use a relay to drive a contactor coil such as the EMAS HN0910NUE.
Can the digital inputs count pulses?
Yes. Each input can be configured as a counter in NXperience, which suits flow meter pulses, production counts and run-hour monitoring.
What happens if communication is lost?
A configurable watchdog drives the relays to a defined safe state if the Modbus master stops communicating.
Industry Applications
- Pump & fan control — switches contactor coils from SCADA or a PLC over Ethernet.
- Alarm & status signalling — drives beacons and sounders while reading alarm and run contacts.
- Remote plant room I/O — brings distant status and control points onto an existing Modbus network.