1791-24B8 Allen-Bradley Block I/O Module

Product parameters

Module type: Discrete I/O Block Module

Series: Allen-Bradley 1791 Block I/O Series

Input/output points:

Input: 24 DC inputs (divided into 3 groups, with 8 inputs in each group

Output: 8 DC outputs (1 group of 8 outputs)

Working voltage:

Input voltage range: 10-30V DC

Output voltage range: 10-30V DC

Nominal voltage: 24V DC

Input voltage in open state: 10-30V DC

Off-state input voltage: Maximum 5V DC (1.5mA)

Input current:

Minimum current in open state: 2.5 mA (11V DC)

Maximum current in open state: 11 mA (30V DC)

Input impedance: 3.4k Ohms

Output current:

Maximum output current:

Vertical installation: 500 mA (60°C), 1 A (30°C)

Horizontal installation: 250 mA (60°C), 500 mA (30°C)

Surge current: 3 A (lasting for 50 ms, repeating every 2 seconds)

Leakage current in off state: 1 mA

Voltage drop: 1V (0.5mA leakage current)

Input signal delay

Fast mode: 1 ms (on), 5 ms (off)

Slow mode: 1 ms (on), 18 ms (off)

Power supply:

External power supply (with internal protection, no fuse required) : 19.2-30V DC, 300 mA

Power dissipation

Maximum power dissipation: 17.1W

Maximum heat dissipation: 58.1 BTU/ hour

Isolation

Power supply to RIO: 500V AC

Group to group: 500V AC

Group to logic: 500V AC

Environmental conditions:

Operating temperature: 0 to 60°C (32 to 140°F)

Storage temperature: -40 to 85°C (-40 to 185°F)

Relative humidity: 5-95% (non-condensing)

Protection grade: IEC IP20 (needs to be installed in an appropriate protection cabinet)

Installation method: Supports horizontal or vertical installation. It can be installed using DIN rails or panels

Terminal type: Detachable screw terminal. The recommended cable is 14 AWG (2 mm²) twisted wire, with a maximum insulation thickness of 3/64 inches

Communication protocol: Supports Remote I/O (RIO) protocol

Baud rate: 57.6K, 115.2K or 230.4K

Maximum cable length: 10,000 feet at 57.6K; It is 5,000 feet at 115.2K. It is 2,500 feet at 230.4K

Recommended RIO cable: Belden 9463

Function

Input/output processing

It provides 24 24V DC input channels, divided into 3 groups, with 8 in each group, supporting the connection of discrete devices such as proximity switches, limit switches, selector switches, float switches and push-button switches.

It provides 8 24V DC output channels (1 group), which can drive actuators such as indicator lights, relay coils, buzzers, solenoid valves, etc.

Inter-group isolation (500V AC) enhances system security.

Built-in power supply and communication interface:

The module has an internal power supply (19.2-30V DC), and no external fuse is required (protection is already included inside).

Supports the Remote I/O (RIO) protocol and is connected to the main controller in a Daisy chain topology via the Belden 9463 cable. Compatible with controllers such as Allen-Bradley's PLC-2, PLC-3, PLC-5, and SLC 500 (requiring a 1747-SN remote I/O scanner).

Configuration flexibility:

The switch components inside the module are used to set the I/O rack number, final status and final rack configuration, facilitating users to customize according to application requirements.

It can be monitored and controlled through the user interface of the PLC.

Fault Diagnosis:

It is equipped with status indicator lights to display the communication status and channel operation conditions, facilitating quick fault diagnosis.

Built-in hardware watchdog function to monitor the operating status of the microprocessor.

Convenience of wiring:

The detachable terminal block design simplifies wiring and module replacement, reducing maintenance time.

It is recommended that users add external fuses to the output channel as needed to enhance protection (the module output does not have built-in fuses).

Compact design: The module integrates rack, adapter, power supply and I/O functions, reducing system complexity and making it suitable for space-constrained distributed control applications.

Application scenarios

Machine control

It is used to monitor and control discrete signals in mechanical equipment, such as proximity switches to detect the position of parts, limit switches to monitor the travel of machinery, or push-button switches to trigger operations.

It is commonly found in packaging machines, conveyor belt systems, assembly lines and other equipment.

Process control: Applied in process automation systems, it monitors the status of liquid level switches (such as float switches), valves or sensor signals.

It is suitable for industries such as chemical engineering, petroleum and natural gas, and water treatment.

Building automation: It is used in building management systems to monitor the status of switches or sensors, such as status detection in access control systems and HVAC systems.

Distributed Control System (DCS)

As a remote I/O module, it communicates with PLC or SLC controllers via the RIO protocol and is suitable for scenarios in large factories or production lines that require decentralized control.

Supports Daisy chain topology, simplifies wiring, and is suitable for long-distance I/O expansion.

Highly compatible automation system: Compatible with multiple Allen-Bradley controllers (such as PLC-2, PLC-3, PLC-5, SLC 500), it is particularly suitable for expanding the input/output points of existing automation systems.

Advantage Products:

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