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SKU: 1756-L55M24
Allen-Bradley 1756-L55M24 GuardLogix Safety Controller Module
The Allen-Bradley 1756-L55M24 is a high-performance GuardLogix controller offering 3.5 MB of non-volatile memory for integrated safety, motion, and discrete control applications.
Product Overview
The Allen-Bradley 1756-L55M24 functions as a high-performance GuardLogix controller within the ControlLogix automation platform. Engineers deploy this processor to manage complex industrial requirements, including integrated safety, motion control, discrete logic, and drive regulation. By leveraging the modular architecture of the ControlLogix chassis, the 1756-L55M24 facilitates scalable system designs that adapt to evolving production needs. Furthermore, the controller utilizes advanced signal processing to ensure deterministic performance across distributed I/O networks.
Technical Specifications
- Manufacturer: Allen-Bradley (Rockwell Automation)
- Model Number: 1756-L55M24
- Product Series: GuardLogix
- Module Type: Safety CPU Module
- User Memory: 3.5 MB (Non-volatile)
- Communication Interfaces: Integrated RS-232 Serial Port
- System Power Draw: 1.25 A @ 5.1V DC
- Power Dissipation: 5.7 W (19.4 BTU/hr)
- Operating Temperature: 0°C to 60°C
- Relative Humidity: 5% to 95% (Non-condensing)
- Physical Dimensions: 3.5 cm x 14 cm x 14.5 cm
- Weight: 0.38 kg
Functional Characteristics and Application
Allen-Bradley engineered the 1756-L55M24 to serve as the central processing unit for mission-critical automation loops. Because the module incorporates non-volatile memory, it retains user programs without relying on internal batteries, which enhances long-term reliability. Additionally, the controller supports hot-swapping within the chassis; however, operators must strictly follow safety protocols and de-energize the system when operating in hazardous environments to mitigate explosion risks. By adhering to these operational guidelines, maintenance personnel effectively preserve system integrity.
The processor supports multiple programming languages, including Relay Ladder, Sequential Function Charts (SFC), Function Block Diagrams, and Structured Text. This multi-language capability allows developers to select the most efficient syntax for specific control tasks, thereby improving overall code readability and execution speed. Furthermore, the unit integrates with a diverse array of communication protocols, such as Ethernet, DeviceNet, and ControlNet, ensuring robust data exchange with secondary field devices. Because the 1756-L55M24 delivers precise safety-rated control, it remains an ideal solution for facilities that prioritize rigorous safety standards and high-speed operational responsiveness.
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Hardware Specifications
| Parameter | Specification |
|---|---|
| Model | 2094-BM02-S |
| Brand | Allen-Bradley |
| Origin | USA |
| Weight | 0.9 kg |
| Dimensions | 3.5 x 13 x 14.5 cm |
| Operating Temp | 0 to +50 deg C (Standard Industrial Range) |
| Power Consumption | 650 VDC nominal input / 115 Ohm internal shunt resistor |
| Module Type | Servo Drive (Axis Module) |
| Product Range | ControlLogix / Kinetix 6000 |
| System Classification | PLC Motion Control |
| Continuous Current | 10.3 A (RMS), 14.6 A (Sine Peak) |
| Velocity Loop Bandwidth | 500 Hz |
| Current Loop Frequency | 1300 Hz |
| Efficiency Rating | 98% |
Industrial Control & Deterministic Driving Network
The Allen-Bradley 2094-BM02-S interacts directly over backplane bus communication velocity networks to achieve microsecond-level synchronization across adjacent drive modules. The hardware features deterministic network compatibility, letting control processors command motion trajectories with minimal jitter. It supports peak enhancement technology, scaling the nominal inverter output profile from a standard 150% threshold up to 250% during peak torque demands. This scaling permits rapid rotor acceleration and deceleration profiles without triggering overcurrent trips. Integrated Safe-Torque Off (STO) hardware circuits provide independent physical galvanic control paths, disabling gating signals to the output power transistors to prevent unexpected motor rotation during active maintenance states.Frequently Asked Questions
Q: What are the backplane current and configuration limits when expanding axis modules on a single rail?A: The module must be inserted into an authorized Kinetix 6000 power rail, supporting up to seven axis modules alongside one master power module. The cumulative peak current draw must not exceed the structural rating of the shared copper backplane link.Q: Is this hardware compatible with live hot-swapping procedures?A: No. The shared 650 VDC bus lines pose arc-flash and component damage hazards. System DC bus voltage must be entirely drained and verified below safe thresholds before seating or unseating the module from the rail structure.Q: Can the internal 115 Ohm shunt resistor handle high-inertia braking loads?A: The internal shunt resistor is designed for short-duration thermal dissipation. High-inertia or cyclic deceleration applications require an external, isolated shunt module to prevent DC bus overvoltage faults.Field Installation Guidelines
- Enclosure Clearance & Thermal Profile: Maintain a minimum enclosure installation depth of 10.7 inches. Ensure unimpeded vertical ventilation spacing above and below the module chassis to prevent heat sink thermal saturation.
- Cable Separation Architecture: Physically isolate unshielded high-voltage power cables, including motor leads and shunt resistor lines, from low-level digital feedback encoder loops and communication wires to suppress cross-talk.
- Shielding and Ground Boundary: Terminate all motor cable shields at the designated grounding clamp on the power rail base. Maintain a low-impedance ground plane across the entire mounting subpanel.
- Overcurrent Protection: Install specified circuit breakers or high-speed semiconductor fuses upstream of the main power distribution block to guard the internal solid-state components against phase-to-phase short circuits.
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