Modbus RS-485 Voltage Input for PLC and Monitoring Systems
Connect voltage-output sensors and signals to PLCs and monitoring systems with the ROI-IOM Series. Four analog voltage inputs accept 0 to 30 V signals, with measurements available through an RS-485-connected embedded I/O platform.
Bring voltage signals onto an RS-485-connected I/O platform
The Robert Owen Inc. ROI-IOM Series provides four analog voltage inputs for measuring 0 to 30 V signals. It is suited to voltage-output sensors and other DC voltage signals that need to be brought into PLC, control, or monitoring applications.
- Four voltage inputs — AV1 through AV4
- 0 to 30 V range — on each analog voltage input
- High input impedance — greater than 450 kΩ
For power, environmental, mechanical, and all other I/O specifications, see the ROI-IOM Series technical specifications .
Voltage input capabilities
- 4 analog voltage inputs: AV1–AV4
- 0 to 30 V input range
- >450 kΩ input impedance
- 12-bit SAR ADC with 8.7 ENOB
- 500 kS/s maximum ADC sample rate with 48 MHz clock
- 15 m maximum specified cable length
Voltage input specifications
Four 0 to 30 V analog inputs
AV1 through AV4 each provide a 0 to 30 V input range with input impedance greater than 450 kΩ, allowing the ROI-IOM to accept common DC voltage signals without requiring separate factory-set voltage-range models.
On-board analog-to-digital conversion
The voltage inputs use a 12-bit SAR ADC specified at 8.7 effective number of bits (ENOB), with a maximum ADC sample rate of 500 kS/s when operated with a 48 MHz clock.
DIN-rail I/O for control and monitoring systems
The ROI-IOM uses a compact three-module DIN-rail enclosure. The voltage-input specification lists a maximum cable length of 15 meters; system wiring and installation should follow the complete ROI-IOM documentation.
RS-485 connectivity for embedded I/O
The ROI-IOM communications interface provides RS-485 half-duplex operation with manual or automatic transmit/receive management. Supported baud rates range from 1200 to 115200.
Voltage measurement path
- Connect the signal — wire the DC voltage source to one of AV1–AV4.
- Acquire the measurement — the on-board ADC converts the voltage input.
- Use the result — integrate the ROI-IOM measurement into the connected PLC, controller, or monitoring application.
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