Allen-Bradley 1769-BOOLEAN Compact I/O Boolean Control Module, 8-In / 4-Out, 24V DC

Description

The 1769-BOOLEAN​ is a Compact I/O Boolean control module for the Allen-Bradley CompactLogix platform, manufactured by Rockwell Automation. It combines eight 24V DC sinking inputs and four 24V DC sourcing outputs in a single 35 mm-wide module, and uniquely adds an onboard Boolean logic processor that evaluates AND, OR, XOR, and NONE expressions locally — independent of the controller scan cycle.

Unlike a standard 1769 digital input or output card, the 1769-BOOLEAN​ does not simply pass field signals to the controller. It reads its physical inputs, evaluates a configured logic expression against those inputs plus eight program-controlled virtual inputs, and drives its outputs in approximately 1 µs — all on the module itself. For high-speed interlocks, reject gates, guard logic, and registration sequences, this removes scan-dependent delay from the critical path and frees the main processor for higher-level coordination.

Application Scenarios

Consider a high-speed case sealer on a packaging line where a photocell, a guard-door interlock, a product-presence sensor, and a jam-detect switch must agree before the conveyor enable is asserted. The CompactLogix processor scans every 10–20 ms, but the mechanical window for a reject decision is under 2 ms. Wiring those four sensors through a conventional input card would force the logic through the scan — and at 600 cases per minute, a one-scan delay mistimes the reject gate often enough to damage product. Instead, the integrator lands the sensors on the 1769-BOOLEAN​ and configures Output 0 = IN0 AND (IN1 OR IN2) AND NOT IN3 as a Boolean expression on the module. The output responds in roughly 1 µs, completely outside the scan, while the controller still sees every input state for logging and HMI display. Nuisance trips from scan jitter disappeared on the first commissioning run .

In a second scenario, a material-handling integrator needed a 2-out-of-3 sensor voting scheme for a diverter gate — a safety-relevant decision that had to remain valid even if the controller was mid-scan or temporarily离线. Rather than add a dedicated safety relay or a second PLC, the team used the 1769-BOOLEAN‘s virtual inputs and on-module expression to build the vote locally. The gate hold-in stayed deterministic, the main program was simplified, and maintenance staff could read the vote status directly from the module’s front-panel LEDs during a fault walk-down .

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