Purchase now: Allen Bradley 1746-IC16 SLC 500 Input Module
Purchase now: Atlantechdrives provides you the 1746-IC16, a highly reliable and robust digital input module engineered by Allen Bradley for the legacy SLC 500 programmable logic controller system. This specific module provides 16 input points and operates on a 48V DC sinking configuration. It is specifically designed to interface with 48V DC sourcing (PNP) field devices, making it an essential component for industrial environments that standardize on 48V DC control circuits, such as telecommunications facilities, heavy utilities, and specialized manufacturing plants. By seamlessly translating high-level 48V DC signals from limit switches, proximity sensors, and pushbuttons into the 5V DC logic required by the SLC 500 processor, the 1746-IC16 ensures accurate and real-time machine control.
Technical Specifications of the 1746-IC16
The 1746-IC16 is built to Rockwell Automation’s exacting industrial standards, providing excellent electrical isolation and signal filtering to prevent false triggering from electrical noise. The module requires a removable terminal block (RTB) for field wiring, allowing for quick replacement without disturbing existing connections within the control panel.
- Part Number: 1746-IC16
- Module Type: Digital Input Module
- Platform: SLC 500 (1746 Series)
- Number of Inputs: 16 Points (1 set of 16)
- Voltage Category: 48V DC
- Operating Voltage Range: 30…60V DC
- Signal Delay (Max): On: 8 ms, Off: 8 ms
- Backplane Current Draw: 85 mA at 5V DC
- Wiring Logic: Sinking (Requires Sourcing/PNP field devices)
- Isolation: 1500V AC between field and backplane
Expert Tips: Understanding Sinking vs. Sourcing
One of the most common issues during installation is mismatched wiring logic. Expert Tip: The 1746-IC16 is a «Sinking» input module. This means the module itself provides the path to ground (DC Common) for the input circuit. Therefore, your field devices (sensors, switches) must be «Sourcing» devices—meaning they supply the positive voltage (+48V DC) to the module’s input terminals. Wiring a sinking sensor (NPN) to this sinking module will result in the input never registering a true signal. Always verify the polarity of your field devices before integrating them into the SLC chassis.
Maintenance and Troubleshooting
Although the SLC 500 is a legacy system, keeping it operational is highly cost-effective for modern plants. Regularly inspect the removable terminal block for loose wires or oxidation, especially in environments with high vibration or humidity. If an input fails to register, use a digital multimeter to verify that a full 48V DC is reaching the terminal when the field device is activated. If the voltage is present but the LED indicator on the module does not illuminate, the internal optocoupler may be damaged, necessitating a module replacement.
Frequently Asked Questions (FAQs)
Q: Is the 1746-IC16 module compatible with all SLC 500 processors?
A: Yes, this module can be placed in any available slot of an 1746 chassis, except for Slot 0, which is strictly reserved for the SLC 500 processor or communication adapter.
Q: Does this module require an external power supply?
A: The module draws its internal logic power (85 mA at 5V DC) directly from the chassis backplane. However, you must provide an external 48V DC power supply for the field devices and the input circuitry.
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