Purchase now: Allen Bradley 1746-IV16 Sourcing Input Module
Purchase now: Atlantechdrives provides you the 1746-IV16, a specialized 16-channel digital input module manufactured by Allen Bradley for the SLC 500 automation platform. This specific module operates on a 24V DC logic level and is engineered with a «Sourcing» electrical configuration. This means the 1746-IV16 provides the positive voltage (+24V DC) to the input circuit, making it specifically designed to interface with «Sinking» (NPN) field devices. It is a critical component for industrial machinery, packaging lines, and CNC centers that utilize NPN proximity sensors, photoelectric switches, and solid-state encoders that switch to ground (DC Common) when activated.
Technical Specifications of the 1746-IV16
The 1746-IV16 provides high-density input capacity without sacrificing signal integrity. It features comprehensive optical isolation to protect the PLC processor from transient voltage spikes originating on the factory floor. The module is divided into groups of inputs that share a common terminal, streamlining the wiring process in complex control panels.
- Part Number: 1746-IV16
- Module Type: Digital Input Module
- Compatible System: Allen Bradley SLC 500
- Number of Inputs: 16 Points
- Voltage Category: 24V DC
- Operating Voltage Range: 10…30V DC
- Wiring Logic: Sourcing (Requires Sinking/NPN field devices)
- Signal Delay (Max): On: 8 ms, Off: 8 ms
- Backplane Current Draw: 85 mA at 5V DC
- Isolation: 1500V AC between field and backplane
Expert Installation Advice: NPN vs PNP Wiring
Mixing up sourcing and sinking logic is the most common reason for installation failure. Expert Tip: The 1746-IV16 is a Sourcing module. You cannot use standard European PNP (Sourcing) sensors with this card. If you connect a PNP sensor to the IV16, the input will never trigger because both the sensor and the module are trying to supply positive voltage. You must exclusively use NPN (Sinking) sensors, which complete the circuit by providing a path to the DC Common (0V). Always verify your sensor logic before wiring the Removable Terminal Block to avoid hours of frustrating troubleshooting.
Maintenance and System Diagnostics
The front panel of the 1746-IV16 is equipped with 16 individual LED status indicators. During routine maintenance, observe these LEDs while the machine is operating. If a field sensor is triggered but the corresponding LED on the module does not light up, check the field wiring for broken connections or a drop in the 24V DC supply voltage. If the voltage at the terminal is dropping below 10V DC, the module will interpret it as an «OFF» state. Ensure your 24V DC power supply has enough amperage capacity to handle all connected NPN sensors simultaneously.
Frequently Asked Questions (FAQs)
Q: What is the difference between the 1746-IB16 and the 1746-IV16?
A: The 1746-IB16 is a «Sinking» input module designed for PNP sensors. The 1746-IV16 is a «Sourcing» input module designed for NPN sensors. They operate on the same voltage but have opposite electrical polarities.
Q: Can I install this module in an expansion chassis?
A: Yes, the 1746-IV16 can be installed in any available slot of a local or remote 1746 expansion chassis, excepting Slot 0 which is reserved for the processor or communication adapter.
Do you need more references from this brand? Explore our full catalog of Allen Bradley here.
For NPN sensor applications, this sourcing module integrates perfectly with the 1746-A7 chassis.
