IOMod 8DI4RO – industrial 8 digital inputs and 4 relay outputs module


IOMod 8DI4RO is a stand-alone Modbus-RTU, IEC 60870-5-101, and IEC 60870-5-103 digital input and digital output controller. Designed to achieve a high technological look and compact fit on DIN rail (EN 60715), IOMod 8DI4RO is used for industrial applications where digital signaling is used and robust communication is essential.

IOMod 8DI4RO is an ideal solution for such applications as data acquisition, observation, control, process monitoring, testing, and remote measurement. It is controlled over Modbus, IEC 60870-5-101 or IEC 60870-5-103 protocol, and can be connected in parallel with other Modbus, IEC 60870-5-101 or IEC 60870-5-103 equipment in a multi-drop installation scheme as in any SCADA system.

When using IOMod 8DI4RO with WCC Lite it is possible to monitor/control the I/O signals over Ethernet LANs or 3G/4G(LTE)/GSM/GPRS networks. It is a powerful solution for remote monitoring and control, alarm management, and data logging of I/O’s on cloud platform.


  • 8 digital inputs
  • Configurable input inversion and digital debounce filter
  • Configurable SPI, DPI, SCO, and DCO support
  • Configurable feedback for outputs with inputs
  • Configurable pulse outputs and permanent outputs
  • Input grouping
  • Output grouping
  • Feedback configurable time
  • 4 relay outputs
  • Galvanically isolated inputs and outputs
  • Configuration over USB console
  • Drag and Drop firmware upgrade over USB mass storage
  • Modbus, IEC 60870-5-101 and IEC-60870-5-103 communication over RS485
  • Software selectable termination resistor on RS485
  • LED indication for input/output and data transmission


  • Digital inputs: 8
  • Relay outputs: 4 (normal outputs contact)
  • PC USB connection: Mini USB
  • Input/output connectors: Screw terminal plug connector


  • Configuration: Over USB and RS485
  • Firmware upgrade: Over USB and RS485


  • Communication standard: RS485
  • Communication protocol: Modbus (RTU), IEC 60870-5-101, and IEC 60870-5-103
  • Speed: 600 – 115200 baud


Device data
Article numberIOMOD-8DI4RO
Product Description8 Digital inputs and 4 relay outputs module
Configuration softwareIOMOD Utility, Serial console (putty)*
Warranty2 years
Inputs and functions
Digital inputs8
Input voltage12-48 VDC
Input signal polarityConfigurable
Input inversionConfigurable
Input filterConfigurable (0..256000ms)
Input groupingUp to 4 groups of DPI
Relay outputs4 (normally open contact)
Output current <5A at 250VAC Resistive load
<2A at 250VAC Inductive load (cos φ = 0.4, L/R = 7 ms)
<5 A at 30 VDC Resistive load
<2 A at 30 VDC Inductive load (cos φ = 0.4, L/R = 7 ms)
(per each output)
Output max switching voltage277 VAC, 125 VDC (max switching current 5A)
Output functionsPermanent or Pulse output
Output pulseConfigurable in ms (0..60s)
Output feedback timeConfigurable in ms (0..60s)
Output groupingup to 2 groups DCO
Interface and communication
RS485 interfaceANSI/TIA/EIA-485-A-1998
Communication protocols– Modbus RTU Slave;
– IEC 60870-5-101 Slave;
– IEC 60870-5-103 Slave.
Baudrate600 – 115200 baud
ParityNone, Even, Odd
Terminating resistors120 Ohm (configurable)
USB interface
TypeMini USB
UseConfiguration/Firmware upgrade
Power supply
Auxiliary power supply9-33VDC (full range)
Power consumption120mA @ 12VDC, 60mA @ 24 VDC, 30mA @ 48 VDC
Insulation voltage3 kV
Operating conditions
Operating temperature-40°C … 85°C
Storage temperature-40°C … 85°C
Relative humiditymax. 95 % (non-condensing)
Protection classIP20
Dimensions and installation instructions
Case height x width x depth119 x 22.5 x 101 mm
Installation typeDIN Rail mounting
* IOMOD Utility is configuration tool for IOMOD devices with firmware v2.x, for devices with fw v1.x configuration can be done via USB port as Serial console interface like Putty.



IOMOD-8DI4RO – 8 Digital inputs and 4 relay outputs module with IEC 60870-5-103, IEC 60870-5-101, Modbus RTU Slave protocols

On request*:


* – IOMOD devices 8DI8DO, 8AI, 4RTD, 16DI, 8DI4RO, HT with firmware versions v1.x supports only 1 protocol. To change protocol is required to change the firmware. All types of firmware are accessible to all customers without any additional payment. For firmware, version v2.x is included all protocols and is configurable with IOMOD configuration tools.

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