Introduction to the Allen-Bradley 1746-IV8
When your SLC 500 control system needs reliable digital input sensing, the Allen-Bradley 1746-IV8 delivers proven performance. This 24VDC sourcing input module provides eight channels in a single group, directly interfacing field devices with your PLC. As part of the trusted SLC 500 series, it installs easily into any vacant chassis slot, drawing just 50 milliamps from the 5VDC backplane. Whether you are maintaining an existing line or upgrading legacy I/O, this module keeps your operation running smoothly.
Technical Specifications That Matter
The 1746-IV8 operates with an input voltage range of 10-30 VDC, giving you flexibility across common industrial power supplies. Each channel draws a nominal 8 milliamps at 24VDC, ensuring compatibility with standard sensors and switches. Signal response is consistent: both ON and OFF transitions feature an 8-millisecond delay, which suits most discrete manufacturing applications. In the off state, the module tolerates a maximum of 5.0VDC and 1 milliamp, preventing false triggers from leakage currents. The single-group design simplifies wiring and troubleshooting, while LED indicators on the front provide immediate channel status.
Key Parameters at a Glance
| Specification | Value |
|---|---|
| Number of Inputs | 8 |
| Input Voltage Range | 10-30 VDC |
| Backplane Current (5VDC) | 50 mA |
| Signal Delay (ON/OFF) | 8 ms |
| Off-State Voltage (max) | 5.0 VDC |
| Off-State Current (max) | 1 mA |
| Operating Temperature | 0 to +60°C |
| Storage Temperature | -40 to +85°C |
| Relative Humidity | 5 to 95% non-condensing |
| Module Type | 24VDC Sourcing Input |
| Series | SLC 500 |
| Slot Width | Single slot |
Why Choose the 1746-IV8 Over Similar Modules?
Compared to other SLC 500 input modules, the 1746-IV8 stands out for its sourcing configuration and wide voltage range. Many legacy 24VDC input modules require external power supplies or offer fewer channels. The 1746-IV8 draws all necessary power from the backplane, eliminating extra wiring. Its 10-30VDC range accommodates both 12V and 24V systems, while the 8ms delay balances noise immunity with responsiveness. For applications needing AC inputs, the 1746-IA8 is a common alternative, but the 1746-IV8 excels in DC environments where sourcing sensors are standard.
Applications and Integration
This module directly interfaces auxiliary contacts, limit switches, proximity sensors, and other signaling devices. In packaging lines, it captures end-of-travel signals from pneumatic actuators. In material handling, it monitors photoeyes and proximity switches on conveyors. The 1746-IV8 integrates seamlessly with any SLC 500 processor, and the number of modules you can use depends on your processor’s I/O capacity and available chassis slots. No external power supply is needed, simplifying panel design.
Installation and Maintenance Essentials
Always remove power from the rack power supply before inserting or removing the 1746-IV8. Hot-swapping can cause electrical arcing, damaging contacts and reducing reliability. Use 14 AWG (2 mm²) wire for signal terminations. The module is open-type equipment intended for industrial environments. For maintenance, inspect connections periodically and verify LED indications match field device states. Operating temperature ranges from 0 to +60°C, so ensure adequate panel ventilation. Store spare modules between -40 and +85°C in low-humidity conditions.
Frequently Asked Questions
Q: Can I use the 1746-IV8 with 12V DC sensors?
A: Yes, the input voltage range is 10-30 VDC, so 12V systems are compatible.
Q: How many 1746-IV8 modules can I install in one chassis?
A: The limit depends on your SLC 500 processor’s I/O capacity and available slots.
Q: What wire size should I use for field wiring?
A: The module requires 14 AWG (2 mm²) cables for signal termination.
Q: Does the 1746-IV8 need an external power supply?
A: No, it draws 50 mA from the 5VDC backplane.
Q: What is the signal delay for this module?
A: Both ON and OFF transitions have an 8 ms delay.
Order Your 1746-IV8 Today
SpareTechPLC stocks the Allen-Bradley 1746-IV8 and other SLC 500 components. Contact us for availability and pricing.
