1746-ITB16 Ser C (PU)

Allen Bradley Bulletin 1746 | DC Input Module

10..30VDC, DC Current sinking 16 Point input module

The Allen-Bradley 1746-ITB16 is an SLC 500 fast response discrete sinking input module featuring 16 channels that accept a nominal input voltage of 24VDC over a 10–30VDC operating range. It is designed specifically for input devices that operate at rapid or high switching frequencies, capturing fast signals as pulses so the controller can recognize and act on them as valid logic signals.

What sets the ITB16 apart from standard DC input modules is its dramatically faster response time. Signal delay is just 0.3ms at ON-state and 0.5ms at OFF-state — a significant improvement over the 8ms delay found on general-purpose modules like the 1746-IB16. When paired with an SLC 5/03 or SLC 5/04 processor using Discrete Input Interrupt (DII) instructions with 100µs polling, the module can read pulse frequencies up to 1kHz. When used with a gray code encoder such as the Allen-Bradley 845D Absolute Gray Code Encoder, pulse frequencies up to 2kHz can be achieved.

The module includes filter circuitry and optical coupling for signal noise reduction, and LED indicators provide at-a-glance input status for easier troubleshooting. Its removable terminal blocks eliminate the need to disconnect wires during module replacement, simplifying maintenance.

The 1746-ITB16 operates between 32–140°F (0–60°C) at 5–95% non-condensing relative humidity, with a maximum power dissipation of 3.6W.

Key Specifications:

• Inputs: 16 (sinking)
• Nominal Voltage: 24VDC (Range: 10–30VDC)
• Backplane Current: 85mA @ 5VDC
• Signal Delay: 0.3ms ON / 0.5ms OFF
• Max Pulse Frequency: Up to 1kHz (2kHz with gray code encoder)
• Platform: SLC 500 (1746 Chassis)
• Series: C