Digital I/O module romod 4DI2DO-R-3P

ModbusRS-485Modbus RTU

Product information
The rail-mounted module romod 4DIO-R (romod 4DI2DO-R-3P) provides two 3-position relay outputs for OPEN‑STOP‑CLOSE control and four digital inputs for signalling operating, error or status messages. It acts as a Local Override/Indication Device (LO/ID) with integrated switches allowing manual override of digital outputs normally controlled via Modbus RTU over RS485. Each 3‑position output is controlled by two switches: one selects Automatic / OFF / Manual override, the other selects OPEN‑STOP‑CLOSE (effective only when the first switch is in Manual).

Digital Outputs
The relay outputs are provided as normally-open (NO) contacts. Switched signals must have the same phase. For each channel, opening and closing run times and over‑/under‑steer times can be parameterized; configured run times apply when outputs are activated via bus commands. Inductive loads should be avoided or suppressed at source.

Digital Inputs
Inputs are driven with 24 V via external dry contacts; the COM terminal defines the reference potential (0 V or 24 V). Inputs can be configured as limit switches so that when an end position is reached the drive stops and the module corrects the calculated blind position to 0% (closed) or 100% (open). If no end position is reached within configured run times in automatic mode, the drive stops for safety; this safety stop does not apply in manual override. Inputs can alternatively be configured to directly control outputs (bypassing configured run times). For AC input control, set edge-detection delay in configuration registers (≥40 ms for 50 Hz) to avoid false detections.

Technical data

• Power supply: 24 V AC/DC, connection via terminals
• Current consumption: typ. 68 mA (DC), 152 mA (AC) with all relays activated
• Power dissipation max.: 1.7 W (DC), 3.7 W (AC) with all relays activated
• DOs: Relay outputs (NO), max. 250 VAC; resistive load characteristics: initial contact resistance 100 mΩ (at 1 A / 24 VDC); rated load 3 A at 250 VAC / 30 VDC; max switching voltage 277 VAC, 30 VDC; max switching capacity 830 VA (AC), 90 W (DC); endurance 100000 ops
• Bus interface: RS485; Protocol: Modbus RTU (8‑N‑1); supported baud rates (autobauding): 9600, 19200, 38400, 57600
• Configuration storage: internal EEPROM, up to 100,000 write cycles
• Environmental: Operating temperature 0…50 °C; Transport/storage 0…70 °C; Relative humidity 10…90% non‑condensing; Protection class IP20