Product Overview
The Allen-Bradley 1746-IV8 is a 24VDC input module from the SLC 500 series, manufactured by Rockwell Automation. This discrete input module features eight (8) 24 Volt DC sourcing input channels in a single group, making it ideal for interfacing limit switches, sensors, and auxiliary contacts with your control system. It occupies a single slot in any SLC 500 chassis and draws 0.050 Amperes at 5 Volts DC from the backplane, eliminating the need for an external power supply. With LED indicators on the front, it provides clear visual status for each channel.
Technical Specifications Breakdown
Key parameters for the 1746-IV8 are listed below for quick reference:
| Feature | Specification |
|---|---|
| Manufacturer | Rockwell Automation |
| Brand | Allen-Bradley |
| Series | SLC 500 |
| Module Type | 24VDC input module |
| Number of Inputs | 8 |
| Number of Groups | 1 |
| Input Voltage Range | 10-30 VDC |
| Input Current (nominal) | 8 mA @ 24V DC |
| Off-state Voltage (max) | 5.0V DC |
| Off-state Current (max) | 1 mA |
| Signal Delay (ON/OFF) | 8 ms each |
| Backplane Current (5V DC) | 50 milliamps |
| Operating Temperature | 0...+60 °C (+32...+140 °F) |
| Storage Temperature | -40°C to +85°C (-40°F to +185°F) |
| Relative Humidity | 5 to 95% without condensation |
Industry Applications
This module excels in discrete manufacturing environments where reliable 24VDC signal detection is critical. Typical applications include monitoring limit switches on conveyor systems, reading sensor outputs in packaging machinery, and interfacing with push-button panels. The 8 ms signal delay ensures consistent response for most industrial processes, while the 10-30 VDC range accommodates varying power conditions. For cost-conscious operations, the module's single-slot design minimizes chassis space usage, reducing overall system footprint.
Installation & Setup Guidance
Before installation, power must be removed from the rack power supply to prevent electrical arcing that could damage the module or adjacent components. Use 14 AWG (2 millimeter) cables for signal termination as specified. The module installs directly into any vacant slot of an SLC 500 chassis and requires no external power supply—it draws 0.050 Amperes at 5 Volts DC from the backplane. Always verify that the host processor supports the additional I/O load.
Maintenance & Reliability
Given the module's operating temperature range of 0...+60 °C and relative humidity tolerance of 5 to 95% without condensation, it is suitable for most industrial enclosures. Periodically inspect the LED indicators and verify signal integrity. Since the module is supplied as open type equipment intended for industrial environments, ensure proper enclosure protection against dust and contaminants. No internal adjustments are required.
Compatibility & Integration
The 1746-IV8 integrates seamlessly with any SLC 500 chassis and processor. It supports sourcing input circuit type, compatible with standard 24VDC sourcing sensors and switches. The number of modules per system is limited only by the host processor's I/O capacity and available chassis slots. Always consult the SLC 500 system manual for maximum configuration limits.
Selection Guide & Purchasing Advice
When selecting a 24VDC input module for your SLC 500 system, the 1746-IV8 offers a cost-effective solution with 8 channels and proven reliability. For applications requiring higher channel counts, consider the 1746-IV16. SpareTechPLC stocks genuine Allen-Bradley modules with full traceability. Please verify current lifecycle status and availability with SpareTechPLC before ordering.
Troubleshooting & Common Issues
If a channel fails to respond, first check the input voltage at the terminal—it must be within 10-30 VDC. Verify that the off-state voltage does not exceed 5.0V DC and off-state current stays below 1 mA. If the LED is off but the input signal is present, inspect wiring for shorts or opens using 14 AWG cables. For persistent issues, test the module in a different chassis slot to rule out backplane faults.
