AV251228A1 in DIN rail enclosure, front three-quarter view

16 resistance inputs to Modbus RTU (RS485), with line monitoring

Article number AV251228A1

The AV251228A1 measures the resistance of each input, from 0 Ω to 50 kΩ, and uses adjustable thresholds to determine the state of the connected circuit: open circuit, short circuit, button pressed, button released or a resistance outside the defined ranges. In addition, the exact resistance per channel can be read in ohms via Modbus RTU. This makes the module suitable both for status detection and for monitoring resistances.

Supply 12 to 24 V DC (±15 %)
Input 16 resistance inputs, 0 Ω to 50 kΩ
Output modbus RTU over RS485; per channel the resistance in ohms and the state (open circuit, short circuit, button pressed or released, undefined range)

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Specifications

Specifications
Supply	12 to 24 V DC (±15 %)
Input	16 resistance inputs, 0 Ω to 50 kΩ
Output	Modbus RTU over RS485; per channel the resistance in ohms and the state (open circuit, short circuit, button pressed or released, undefined range)
Setup	Modbus address with two rotary switches (x10 and x1)
Baud rate	9,600 to 921,600 bps, 19,200 bps as delivered
Dimensions	90 x 80 x 40 mm with DIN rail enclosure
Mounting	DIN rail

Connections

Connections
Terminal	Function
Terminal 1	Supply plus (IN)
Terminal 2	Earth, E (IN)
Terminal 3	Supply minus (IN)
Terminal 4	RS485 A (IN)
Terminal 5	RS485 B (IN)
Terminal 6	RS485 0 V (IN)
Terminal 7 – 22	Inputs IN1 to IN8, a minus and a plus terminal per input (IN1: terminal 7 minus, terminal 8 plus)
Terminal 23	Supply plus (OUT)
Terminal 24	Earth, E (OUT)
Terminal 25	Supply minus (OUT)
Terminal 26	RS485 A (OUT)
Terminal 27	RS485 B (OUT)
Terminal 28	RS485 0 V (OUT)
Terminal 29 – 44	Inputs IN9 to IN16, a plus and a minus terminal per input (IN9: terminal 29 plus, terminal 30 minus)

Datasheet (PDF)PDF, 128 kB

Application

Building management systems (BMS)
Industrial automation
Smart buildings
Monitoring many switches and sensors with a resistance output

16-channel measuring modules to Modbus RTU

These measuring modules measure 16 inputs and place the values in Modbus registers, to be read via Modbus RTU over RS485 by a PLC, controller or SCADA system. The baud rate is adjustable from 9,600 to 921,600 bps, 19,200 bps on delivery. Supply 12 to 24 V DC (±15 %); dimensions with DIN rail enclosure 90 x 80 x 40 mm. On request: Modbus TCP over Ethernet, an isolated RS485 port, a different measuring range or a different input type.

The voltage module measures the voltage per channel, up to 24 V, for analogue and digital signals. The AV251228A1 measures the resistance per channel (0 Ω to 50 kΩ) and reports open circuit, short circuit and whether a button is pressed or released.

More about the Modbus-16 series