Allen Bradley1771-IVDriver Logic DC Input Module, 8 Point, 12-24 V DC, 1771 I/O Chassis

Product Description

What this part is: Allen-Bradley 1771-IV driver logic DC input module. Product Type: 12 to 24 V DC discrete input module for the 1771 I/O platform. Function: converts DC field signals to the logic level the processor reads, driving the corresponding bits in the data table directly. Points: 8. Input Voltage: 12 to 24 V DC. Backplane Current: 74 mA. Mounting Type: 1771 I/O chassis slot. Unit Quantity: 1 Pc. Decoding the designation: 1771 — the Allen-Bradley 1771 I/O platform, the rack-based I/O family served by PLC-2, PLC-3 and PLC-5 processors. IV — the 8-point 12 to 24 V DC driver logic input module within that platform, the current-sinking counterpart to the 1771-IB current-sourcing module on the same voltage. Electrical data: Input Voltage: 12 to 24 V DC. Input Configuration: 10 to 60 V DC source, sink load. Points: 8. Maximum Off-State Current: 3 mA. Signal Delay: 15 ms ±7 ms on-state, 15 ms ±7 ms off-state. Backplane Current: 74 mA. Signal Type: discrete on/off. What these specs mean in practice: Input Configuration: source, sink load. The module sinks current from a solid-state driver output, which is what makes it the right card for TTL-level and transistor driver stages feeding a PLC rather than dry contacts on a 24 V supply. Maximum Off-State Current: 3 mA. That is the leakage the module tolerates from a solid-state driver’s off state and still registers a genuine off, so a transistor with leakage does not hold a bit true. Signal Delay: 15 ms nominal each way. The delay is filtering, and it is what keeps contact bounce and electrical noise from producing false transitions on a 24 V control circuit. Backplane Current: 74 mA. A light chassis load, so a rack can be filled with these against a 1771-P series supply without pressing the 5 V DC budget. Points: 8. Eight field devices land on one slot. Mounting data: Mounting Type: single slot in a 1771 I/O chassis. Terminations: removable field wiring arm. Controller Platform: PLC-2, PLC-3 and PLC-5 processors using the 1771 I/O structure. Quantity and configuration: Unit Quantity: 1 Pc. One input module. Interchange guidance: Manufacturer Status: discontinued. Part Number: 1771-IV. MPN Variants: 1771IV, 1771 IV, DUB. The 1771-IB is the 12 to 24 V DC input module on the same voltage in the sourcing configuration, so the two differ in field wiring polarity rather than in rating. The 1771-IVN is the 32-point member of the same driver logic family.