Allen-Bradley 1336-L6/B Logic Module

Allen-Bradley 1336-L6/B Logic Module: Precision Drive Control for Production Line Efficiency

The Allen-Bradley 1336-L6/B is a logic interface module engineered specifically for the 1336 PLUS series of AC variable frequency drives (VFDs). In modern industrial environments where equipment uptime and replacement lead time directly affect production continuity, the 1336-L6/B plays a critical role in bridging the gap between the control layer and the drive execution layer. By ensuring clean, reliable signal communication between the PLC controller and the drive unit, this module eliminates erratic drive behavior, reduces unnecessary motor restarts, and enables precise speed regulation — all of which translate directly into measurable operational stability on the production floor.

Designed for seamless integration within Rockwell Automation’s drive ecosystem, the 1336-L6/B supports deterministic command execution, allowing plant engineers to implement maintenance-focused motor control strategies such as ramp-controlled acceleration, load-based speed adjustment, and coordinated multi-drive sequencing. These capabilities are essential for facilities targeting reduced peak demand charges and improved overall equipment effectiveness (OEE).

Product Specification Table

System Compatibility and Application

The 1336-L6/B does not operate in isolation — its value is fully realized when deployed within a coordinated automation architecture. In a typical energy-optimized production cell, a ControlLogix L7x controller issues speed reference commands through a 1756-DNB DeviceNet Bridge module, which routes instructions to the 1336 PLUS drive via the SCANport interface where the 1336-L6/B resides. This tight integration ensures that every speed change command is executed with minimal latency, preventing the energy spikes associated with uncontrolled motor acceleration.

For facilities running multi-axis conveyor or packaging lines, the 1336-L6/B works alongside PowerFlex 70 or PowerFlex 700 drives on adjacent machine sections, enabling a unified drive management strategy across the line. Condition monitoring is typically handled upstream by a PowerMonitor 1000 or PowerMonitor 5000 unit, which captures real-time kWh consumption data and feeds it back to the control system — allowing the ControlLogix program to dynamically adjust drive speed references based on actual load demand rather than fixed setpoints.

On the I/O side, 1756-IB16 digital input modules and 1756-OB16E digital output modules handle discrete feedback signals from motor thermal sensors and drive fault relays, ensuring that the 1336-L6/B receives clean enable/disable signals. For analog speed references, 1756-IF8 analog input modules provide 4–20 mA process variable signals that the drive uses to modulate output frequency in real time. This closed-loop arrangement is fundamental to achieving energy efficiency — the motor runs only as fast as the process demands, never faster.

In facilities where operator visibility is a priority, a PanelView Plus 7 HMI terminal connected via EtherNet/IP provides real-time drive status, operating load trends, and fault history — giving maintenance teams the data they need to act before a drive fault causes unplanned downtime. The 1336-L6/B’s reliable command interface ensures that HMI-initiated speed changes and emergency stops are executed immediately and consistently.

Maintenance and Replacement Notes

In real-world production environments, the most significant sources of unplanned downtime are uncontrolled motor starts, fixed-speed operation under variable loads, and frequent unplanned stops caused by drive communication faults. The Allen-Bradley 1336-L6/B directly addresses all three.

By providing a stable, noise-immune logic interface between the PLC and the 1336 PLUS drive, the 1336-L6/B eliminates the nuisance trips and communication timeouts that force operators to manually restart drives — each restart cycle consuming a surge of current that can be 6–8 times the motor’s rated full-load amperage. In a facility running 10–20 drive-controlled motors, eliminating even two or three unnecessary restarts per shift can reduce monthly operating load by a measurable percentage.

Furthermore, the 1336-L6/B enables the implementation of ramp-controlled acceleration and deceleration profiles within the 1336 PLUS drive parameters. Smooth ramp-up reduces mechanical stress on couplings, gearboxes, and conveyor belts — extending component life and reducing maintenance intervals. Smooth ramp-down allows kinetic energy to be managed rather than dissipated as heat, particularly valuable in applications with high-inertia loads such as centrifuges, large fans, or heavy conveyor systems.

For pump and HVAC applications, the 1336-L6/B supports the implementation of PID-based flow control through the 1336 PLUS drive’s built-in process control functions. Rather than running a pump motor at full speed and throttling flow with a mechanical valve — a notoriously inefficient approach — the drive modulates motor speed to match actual flow demand. This alone can reduce pump operating load by 30–50% in variable-flow systems, a saving that compounds across every operating hour of the year.

All units supplied by ZYPLC undergo functional bench testing prior to shipment, verifying communication integrity, command response, and fault relay operation. Stock is maintained for prompt dispatch, and every 1336-L6/B is covered by a warranty terms confirmed during quotation from the date of delivery.

Product Sourcing FAQ

Q1: How does the 1336-L6/B contribute to operational stability compared to operating the 1336 PLUS drive without a logic interface module?
Without a properly functioning logic interface module, the 1336 PLUS drive relies on hardwired discrete signals for start/stop and speed reference, which limits the control system’s ability to implement dynamic speed adjustment. The 1336-L6/B enables full SCANport communication, allowing the PLC to send precise speed references, read drive feedback in real time, and implement load-adaptive control strategies — all of which reduce unplanned downtime from over-speed motor operation and unnecessary idle running.

Q2: Is the 1336-L6/B compatible with both the original 1336 PLUS and the 1336 PLUS II drive series?
Yes. The 1336-L6/B is designed for use across the 1336 PLUS family, including the 1336 PLUS II variant. It occupies the logic interface slot on the drive’s option board bay and communicates via the SCANport protocol, which is consistent across both series. Always verify the drive’s firmware revision and option board slot configuration against the 1336-L6/B installation manual before installation.

Q3: What is the recommended replacement or upgrade path if the 1336 PLUS drive series is being phased out in our facility?
For facilities migrating away from the 1336 PLUS platform, Rockwell Automation recommends transitioning to the PowerFlex 753 or PowerFlex 755 drive series, which offer native EtherNet/IP connectivity, integrated condition monitoring, and significantly enhanced diagnostic capabilities. During the transition period, maintaining a spare 1336-L6/B module ensures continuity of production on existing 1336 PLUS-equipped machines while the migration is planned and executed in stages.

Q4: What does the warranty terms confirmed during quotation cover, and what is the testing process before shipment?
Every 1336-L6/B supplied by ZYPLC is functionally tested on a compatible 1336 PLUS drive platform prior to shipment. Testing verifies SCANport communication establishment, command response (start, stop, speed reference), fault relay output, and board-level power integrity. The warranty terms confirmed during quotation covers failures attributable to manufacturing defects or latent component faults under normal operating conditions. Damage resulting from incorrect installation, overvoltage events, or physical mishandling is excluded. Contact our technical team at plc.sales@zyplc.com for warranty claims or pre-purchase technical consultation.