Product Description:

The Allen-Bradley 1746-IV16 is a discrete (digital) input module designed for use in SLC 500 PLC systems. It provides 16 input points that interface with field devices supplying 24V DC signals. This module is commonly used to detect the on/off status of sensors, switches, and other discrete devices in industrial automation applications. As the SLC 500 is a mature product line, these modules are typically found in existing installations or acquired through surplus/refurbished channels.

Key Features:

• 16 DC Input Channels: Provides 16 discrete input points.
• 24V DC Sourcing Inputs: Accepts 24V DC input signals. "Sourcing" means the module provides the current when the input is active.
• Non-Isolated Inputs: Inputs are not galvanically isolated from each other or the backplane.
• Removable Terminal Block: Simplifies wiring and maintenance.
• SLC 500 Compatibility: Designed for use in SLC 500 chassis.

Technical Specifications:

• Number of Inputs: 16
• Input Voltage: 24V DC nominal (10-30V DC operating range)
• Input Current: 85 mA maximum per input
• Input Type: Sourcing (PNP)
• Isolation: Non-isolated
• Backplane Current Load: 5V DC @ 150 mA
• Module Location: Any I/O slot in an SLC 500 chassis
• Wiring: Removable terminal block

Applications:

• General Purpose Digital Input Applications: Detecting on/off states of various field devices.
• Machine Control: Monitoring limit switches, push buttons, and other machine status indicators.
• Process Automation: Interfacing with discrete sensors in process control systems.

Why Was the 1746-IV16 Used?

The 1746-IV16 was a popular choice due to its:

• Simplicity: Easy to understand and implement in SLC 500 systems.
• Reliability: Proven track record in industrial environments.
• Cost-Effectiveness (at the time): Provided a cost-effective solution for basic digital input needs.