905U-K Wireless I/O

Key Features:

The ELPRO 905U-K Wireless I/O is a small I/O transmitter that extends long-range, license-free communications to sensors in local, remote, or difficult-to-reach locations. Designed for low power consumption and easy plug-in of ELPRO BU-5 battery packs, the ELPRO 905U-K provides reliable continuity in environments typical of industrial applications with power constraints.
• 902–928 MHz frequency and up to 1W RF power
• Link process inputs to single or multiple outputs (peer to peer)
• Multiple power supply options, including battery-only supply with ultra-low power consumption
(reverts to sleep mode)
• Input-only transmitter unit (2 or 4 DI/PI, 1 AI) that can be connected to multiple I/O and/or gateway units,
with up to 3000 units in a system
• Peer-to-peer communications with exception reporting, reliable self-checking via update time.
and secure data encryption
• External inputs plus internally calculated values, including analog set point status, pulse rate and pulse total, power/battery supply voltage, and power supply alarm
• Can connect to up/down counter transducers, such as shaftencoders
• Configurable repeat transmissions to enhance message reliability
• Set point, pulse count, and rate available. Additional Internal I/O points provided for health monitoring
• Class I Div 2 hazardous areas approval (US/Canada)

Product Details

Transmitter and Receiver


902–928 MHz

915–928 MHz

Transmit power



Frequency hopping spread spectrum (FHSS)


Frequency shift keying

Channel spacing

50 x 250 kHz

Data rate

19.2 kbps with forward error correction

Range (LoS)

20 miles (32 km) @ 4W a c EIRP

9.3 miles (15+km) @ 1W EIRP (other countries)

Antenna connector Female SMA standard polarity

Input and Output

Digital inputs

TTL voltage 0–1.5 Vdc (on), 3.5–13 Vdc (off)

Surge protected, not isolated

Voltage-free/NPN contacts

2 DI (external, status)

Analog inputs

0–24 mA or 0–10V (selectable, over range indication 0–25 mA) Floating differential inputs,
common mode voltage 27V, Resolution 12-bit, accuracy <0.1% 24 Vdc @ 50 mA for external loops provided

Pulse inputs

As per digital input specifications Above.

Maximum pulse rate 10 kHz (50 kHz possible on PI1 using a configurable divider).

Pulse width minimum 0.2 ms, volt-free contacts 300 Hz.

2 PI (pulse total, count, rate).

Serial Port

RS-232 9-pin DB-9 female connector (used for programming only)

Data rate (bps) 9600 bps

Serial settings 8 data bits, 1 stop, no parity

Protocols and Configuration

System address Configurable system address

Protocols supported ELPRO WIBnet™ up to 4 retries, CRC error checking

User configuration E-series configuration utility

Configurable parameters

Individual I/O mappings, analog and digital debounce, update time, analog set points and sensitivities

Security 64-bit encryption on radio

LED Indication and Diagnostics

LED indication OK/active, TX/link (refer to product manual for further information)

Reported diagnostics I/O status

Power Supply

Nominal supply 6–30 Vdc, under/over voltage protection

9 Vdc battery supply

Average current draw

10 mA @ 12 Vdc (idle) + analog loop 2 (internally generated, 24 Vdc/50 mA)

Transmit current draw 300 mA @ 12 Vdc

Battery (optional ELPRO BU5-2)

6 x AA alkaline batteries 9V, up to 1.4 year service life depending on input configuration

Enclosure: specifications as per 905U-K enclosure

Temperature: dependant on battery type used


Temperature rating –40 to +140°F (–40 to +60°C)

Humidity rating 0–99% RH noncondensing


EMC FCC Part 15; AS 3548

RF (radio) FCC Part 15.247; RSS 210; AS 4268.2

Hazardous area CSA Class I, Division 2

Safety IEC 60950 (RoHS compliant)