Modbus RTU N

Modbus RTU N is a family of industrial I/O modules for an RS-485 Modbus RTU bus: 8 digital inputs and 8 outputs, 8 analog inputs or 8 analog outputs in the same housing for a 35 mm DIN rail. DC 7…36 V supply with isolated power and RS-485; the address and baud rate are set by a Modbus command. The modules bring status and alarm signals and readings of 4–20 mA and 0–10 V sensors into a SCADA system or BMS and control valves, dampers and variable-frequency drives.

Features

Three module types in the same housing: 8 DI + 8 DO, 8 AI or 8 AO;
RS-485 Modbus RTU: address 1…255, up to 256,000 bit/s;
DC 7…36 V supply, isolated power and RS-485;
Resettable fuse, TVS and reverse-polarity protection;
AI: 12-bit, current or voltage selectable per channel;
DO up to 500 mA: DI linkage and pulse modes;
Applications: status and alarm signals in BMS, 4–20 mA and 0–10 V sensors, valves, dampers, VFD setpoints, I/O expansion over RS-485.

Specifications

General

Supply voltage, V	DC 7…36
Galvanic isolation	power supply and RS-485
Channel isolation: DI/DO · AI/AO	optical · magnetic
Fuse	resettable
Protection	TVS, reverse polarity
Indicators	RXD, TXD, STATUS; 16 channel LEDs on the DI/DO module

Communication

Interface, protocol	RS-485, Modbus RTU (slave)
Baud rate, bit/s	4800…256,000
Factory settings	9600 bit/s, 8N1, address 1
Parity	none, even, odd
Device address	1…255; 0 for broadcast
Function codes, hex: DI/DO · AI · AO	01 02 03 05 06 0F 10 · 03 04 06 10 · 03 06 10
Line termination, Ω	120, external

Construction

Dimensions with terminals, mm	72 × 121 × 34
Height without terminals, mm	102.5
Mounting	35 mm DIN rail, modules side by side with no gap
Wiring	power on the top terminal block, RS-485 on the bottom one; signal terminals on both
Address and baud rate setting	by Modbus command (registers 4000 and 2000); no switches on the housing

Supply

Scope of delivery	module, product passport, packaging
Warranty	12 months from commissioning, but no more than 18 months from the date of manufacture

Documentation

Datasheets

Datasheet PDF

Versions

Part number	Version
RTU-N-8DIO	8 DI 5…36 V: dry contact, NPN, PNP; 8 open-drain DO, 5…36 V, up to 500 mA per channel.
RTU-N-8AI	8 AI: 0–5 / 1–5 V and 0–20 / 4–20 mA, differential or single-ended; 12-bit, accuracy ≤ 3 %, 25 Hz; factory default: current, 0–20 mA.
RTU-N-8AI-10	8 AI: 0–10 / 2–10 V and 0–20 / 4–20 mA, differential or single-ended; 12-bit, accuracy ≤ 3 %, 25 Hz; factory default: voltage, 0–10 V.
RTU-N-8AO-I	8 AO, current 0–20 mA; 12-bit (1 µA), accuracy ±0.03 mA; 20 mA into a 500 Ω load at a supply of 14 V or more.
RTU-N-8AO-U	8 AO, voltage 0–10 V; 12-bit (1 mV), accuracy ±0.01 V; up to 100 mA per channel.