Why the 1746-IA16 Remains a Workhorse in SLC 500 Systems
Downtime in a PLC-controlled line often traces back to a single failed I/O card. The Allen-Bradley 1746-IA16 digital AC input module keeps SLC 500 systems running by providing sixteen reliable input channels in a single chassis slot. As a genuine Allen-Bradley component from Rockwell Automation, it delivers the dependable field interface that plant engineers count on for immediate replacement.
Technical Specifications That Matter
The 1746-IA16 is built for 100-120V AC signal environments, with an operating voltage range of 85-132V AC at 47-63 Hz. Each of its sixteen input channels draws 12 mA nominal at 120V AC, while the module consumes 85 milliamps from the 5V DC backplane. These ratings let you match the module directly to standard AC pilot devices without adding interface relays.
Signal timing is equally practical. The ON delay reaches a maximum of 35 milliseconds, and the OFF delay maxes out at 45 milliseconds. The module tolerates a maximum OFF-state voltage of 30V AC and an OFF-state current of 2 milliamps, which helps prevent false triggering from leakage in long field wiring runs. Inrush current duration peaks at 500 microseconds with a maximum inrush of 0.8 mA, so the input circuit handles the initial surge from AC sensors and switches without nuisance trips.
Installation and Compatibility
The 1746-IA16 occupies one slot in any SLC 500 chassis, whether fixed or modular hardware, locally or in an expansion rack. Its removable terminal block uses twenty terminals, with terminals 18 and 19 serving as internally connected commons. That removable block means you can swap the module without re-terminating every field wire, cutting replacement time dramatically.
For I/O connection, the module pairs with 1746-HT and 1746-HCA cables. Note that the 1746-IA16 does not include internal protection circuitry, so any AC input device you terminate must be compatible with the SLC 500 input circuit inrush current. For 200/240V AC operation, the counterpart part number is 1746-IM16.
Where the 1746-IA16 Fits Best
General-purpose input applications are the module's sweet spot. In a typical packaging line, it might read photo-eye sensors, limit switches, and pushbuttons across a conveyor section. In a material handling retrofit, it can bring AC proximity sensors into an existing SLC 500 rack without a full controller upgrade. Because the module accepts 85-132V AC directly, it simplifies wiring in panels where AC field devices are already standard.
Supply Assurance from SpareTech Plc
SpareTech Plc stocks genuine Allen-Bradley spares like the 1746-IA16 and ships them worldwide, so you can get the right module fast. Our technical team helps you confirm compatibility with your SLC 500 chassis and field devices before you order. Contact SpareTech Plc today for pricing and availability.
Frequently Asked Questions
What voltage range does the 1746-IA16 accept?
The module accepts an 85-132V AC input signal range, with a 100-120V AC voltage category and 47-63 Hz operating frequency. For 200/240V AC operation, use the 1746-IM16 instead.
How many inputs does the 1746-IA16 provide?
It provides sixteen input channels with sixteen points per common, all housed in a single SLC 500 chassis slot.
What are the signal delay times?
The ON delay is a maximum of 35 milliseconds, and the OFF delay is a maximum of 45 milliseconds.
Does the 1746-IA16 include internal protection circuitry?
No. The module does not offer internal protection circuitry, so any AC input device connected to it must be compatible with the SLC 500 input circuit inrush current.
What cables connect to the 1746-IA16?
The module uses 1746-HT and 1746-HCA I/O connection cables.
