Purchase now: Allen-Bradley 1756-IC16 Digital Input Module
Purchase now: Atlantechdrives provides you the 1756-IC16, a highly robust, industrial-grade 16-point 48V DC digital input module meticulously engineered by Rockwell Automation for the ControlLogix 1756 programmable automation controller (PAC) platform. While 24V DC is the standard in most modern factories, highly specialized industries—such as heavy rail transportation, electrical power substations, legacy telecommunications facilities, and heavy mining operations—frequently standardize their control voltages at 48V DC. This higher voltage provides significantly greater immunity to electromagnetic noise and allows for much longer physical wire runs across vast plant floors without suffering from crippling voltage drops. The 1756-IC16 serves as the perfect interface to bridge these 48V DC field devices—like heavy-duty switchgear auxiliary contacts, substation relays, and rugged proximity sensors—directly into the high-speed ControlLogix backplane, digitizing their ON/OFF states for rapid, deterministic logic execution by the main processor.
Technical Specifications of the 1756-IC16
The 1756-IC16 is designed as a Sinking input module with robust internal opto-isolation to protect the sensitive 5V DC silicon logic of the PLC backplane from harsh external transients and field-induced voltage spikes.
- Part Number: 1756-IC16
- Platform: ControlLogix 1756 System
- Input Type: Digital DC Input (Sinking)
- Number of Inputs: 16 Points
- Operating Voltage Range: 30…60V DC
- Nominal Input Voltage: 48V DC
- Maximum Input Current: 6 mA at 60V DC per channel
- Required Terminal Block (RTB): 1756-TBCH or 1756-TBS6H (Sold separately)
- Backplane Current Draw: 105 mA at 5.1V DC; 2 mA at 24V DC
Expert Tips: The 48V DC Advantage and Cable Distances
When engineering a sprawling industrial facility, selecting the correct control voltage is a critical design decision. Expert Tip: A major advantage of utilizing the 1756-IC16 with a 48V DC control architecture instead of a standard 24V DC system relates directly to Ohm’s Law and voltage drop. Because the voltage is doubled, the electrical current required to drive the input opto-isolator is halved. This means you can run your sensor field wires twice as far across the factory floor before the natural resistance of the copper wire degrades the signal below the module’s «ON» state threshold. If you have limit switches located hundreds of meters away from your main control cabinet, upgrading those specific circuits to 48V DC and using the 1756-IC16 is often more reliable than running sensitive 24V DC signals over massive distances.
Installation Advice: Sinking Architecture and Sensor Polarity
Because the 1756-IC16 is a Sinking module, its internal circuitry provides the path to the DC negative (Common). For the module to successfully register an input as «ON», the physical field device must supply the positive +48V DC voltage to the terminal. Therefore, if you are connecting solid-state proximity or photoelectric sensors to this module, they must absolutely be Sourcing (PNP) type sensors rated for 48V DC operation. Attempting to connect a Sinking (NPN) sensor will result in a failure to read, as both the sensor and the input channel will be searching for a path to ground with no positive voltage flowing between them.
Frequently Asked Questions (FAQs)
Q: Can the 1756-IC16 operate on a 24V DC circuit?
A: No. The minimum guaranteed «ON» state voltage for the 1756-IC16 is 30V DC. If you apply 24V DC to the input terminal, the module will likely not register the signal or will act highly erratic. You must use the 1756-IB16 for 24V DC applications.
Q: Does this module require an external power supply?
A: The module’s internal logic is powered by the ControlLogix backplane. However, you must provide a dedicated, external 48V DC bulk power supply to your field devices and route the 48V DC common to the module’s Removable Terminal Block (RTB) to complete the circuit.
Do you need more references from this brand? Explore our full catalog of Allen-Bradley here.
This 48V DC input card is a specialized choice for industrial networks requiring a deterministic link via the 1756-CN2 bridge module.
