Allen-Bradley 1756-L73 – 8 MB User Memory Controller | ControlLogix 5570 Platform
工程背景 / Engineering Background
The 1756-L73 is a high-performance programmable logic controller (PLC) from Rockwell Automation’s ControlLogix 5570 series, designed for demanding industrial automation applications requiring large memory capacity, deterministic real-time control, and seamless integration with distributed I/O and motion systems. With 8 MB of user memory, it supports complex ladder logic, function block, structured text, and sequential function chart programs simultaneously within a single chassis.
产品定位 / Product Positioning
The 1756-L73 targets mid-to-large scale process control, discrete manufacturing, and hybrid automation environments where memory-intensive applications, multi-axis motion coordination, and high-speed data acquisition are critical. It is the preferred controller for engineers upgrading from legacy PLC-5 or SLC 500 platforms seeking modern Ethernet/IP-native architecture without compromising determinism.
Complete Technical Specifications
| Catalog Number | 1756-L73 |
| Series | ControlLogix 5570 |
| User Memory | 8 MB |
| I/O Memory | Shared from user memory pool |
| Tasks Supported | 32 tasks (1 continuous + 31 periodic/event) |
| Programs per Task | 100 |
| Communication Ports | USB (Type B, programming); EtherNet/IP via 1756-EN2T/EN3TR modules |
| Backplane Communication | ControlLogix backplane (1756 chassis) |
| Execution Speed | Boolean: 0.8 ns/instruction; Floating Point: 1.6 ns/instruction |
| Motion Axes | Up to 100 axes (with SERCOS or EtherNet/IP motion modules) |
| Energy Storage Module | 1756-ESMCAP / 1756-ESMNSE (optional, replaces battery) |
| Battery | 1756-BA2 (optional, for memory backup) |
| Operating Temperature | 0 °C to 60 °C (32 °F to 140 °F) |
| Storage Temperature | -40 °C to 85 °C |
| Relative Humidity | 5% to 95% non-condensing |
| Power Consumption | 4.5 W (from 1756 chassis power supply) |
| Dimensions (H × W × D) | 94.0 mm × 44.5 mm × 141.0 mm |
| Weight | Approx. 250 g |
| Certifications | UL, CE, C-Tick, ATEX Zone 2 (with 1756-A4/K chassis) |
| Programming Software | Studio 5000 Logix Designer v21.00 or later |
| Firmware | Upgradeable via ControlFLASH or Studio 5000 |
Proven Application Environments
- Automotive Assembly Lines — Multi-axis coordinated motion control with high-speed I/O synchronization across multiple chassis
- Oil & Gas Processing — SIL-capable configurations with redundant controller pairs (1756-L73 + 1756-L73S) for safety-critical loops
- Water & Wastewater Treatment — Distributed SCADA integration via EtherNet/IP with remote I/O across geographically dispersed sites
- Pharmaceutical Manufacturing — 21 CFR Part 11 compliant audit trail logging with large memory for recipe management and batch control
- Power Generation & Utilities — High-availability configurations with redundant power supplies and hot-standby controller pairs
- Material Handling & Conveyor Systems — Event-driven task architecture for precise timing of sortation, diverting, and accumulation zones
Engineering Advantages
- 8 MB User Memory — Accommodates large, complex programs with extensive data tables, HMI tag databases, and motion profiles without memory constraints
- Deterministic Execution — Sub-millisecond periodic task execution with jitter <1 µs, critical for high-speed process control and motion synchronization
- Scalable Architecture — Supports up to 31 chassis in a single system via ControlLogix backplane bridging and remote I/O expansion
- Integrated Motion — Native CIP Motion support for up to 100 coordinated axes without external motion controllers
- Redundancy Ready — Compatible with 1756-RM2/A redundancy modules for hot-standby controller configurations with sub-100 ms switchover
- Firmware Flexibility — Field-upgradeable firmware supports backward compatibility with legacy ControlLogix programs
- Energy Storage Option — Capacitor-based 1756-ESMCAP eliminates battery maintenance while providing non-volatile memory protection
System Architecture & Signal Flow
The 1756-L73 resides in a 1756 ControlLogix chassis alongside communication, I/O, and motion modules. The controller communicates with all modules via the high-speed ControlLogix backplane (500 Mbps). Program execution follows a deterministic scan cycle: Input Scan → Program Execution → Output Scan → Communication Servicing. EtherNet/IP communication modules (e.g., 1756-EN2T) provide upstream connectivity to SCADA, MES, and historian systems. For redundant configurations, the 1756-RM2/A module synchronizes memory state between primary and secondary controllers at each scan cycle, enabling bumpless switchover upon primary fault detection.
Typical System BOM (Bill of Materials):
- 1756-A7 or 1756-A10 Chassis
- 1756-PA75 or 1756-PB75 Power Supply
- 1756-L73 Controller (this unit)
- 1756-EN2T EtherNet/IP Communication Module
- 1756-IB16 / 1756-OB16E I/O Modules
- 1756-ESMCAP Energy Storage Module (recommended)
Sourcing & Quality Verification
Konmask.com sources the 1756-L73 through authorized distribution channels and verified surplus markets. Every unit undergoes the following verification process before listing:
- Visual Inspection — Housing integrity, label authenticity, connector condition, and absence of counterfeit indicators
- Firmware Version Check — Confirmed via Studio 5000 or RSLinx Classic connection; firmware version documented and disclosed
- Functional Power-On Test — Controller boots to RUN-FAULT-free state; USB and backplane communication verified
- Memory Integrity Test — Full 8 MB user memory read/write cycle completed without errors
- Provenance Documentation — Chain of custody records available upon request for critical applications
Stock condition is clearly labeled: New Sealed, New Open Box, or Tested Surplus. Condition affects pricing and lead time — contact us for current availability.
Procurement Process
- Submit RFQ — Contact [email protected] with quantity, required condition, and target delivery date
- Receive Quote — Pricing, lead time, and stock condition confirmed within 1 business day
- Order Confirmation — Purchase order or online checkout; proforma invoice issued for wire transfer payments
- Quality Check & Dispatch — Unit re-inspected, ESD-packaged, and shipped with tracking via DHL / FedEx / SF Express
- Post-Delivery Support — Technical assistance available for installation, firmware upgrade, and Studio 5000 configuration
Lead Time: In-stock units ship within 1–3 business days. Special-order or factory-new units: 4–8 weeks.
Minimum Order: 1 unit.
Payment: T/T Wire Transfer, PayPal, Credit Card (via Shopify Payments).
Technical FAQ
Q: Is the 1756-L73 compatible with RSLogix 5000?
A: Yes. RSLogix 5000 v20 and earlier are compatible. For v21+, Rockwell rebranded the software as Studio 5000 Logix Designer. Both use the same .ACD project file format.
Q: What is the difference between 1756-L73 and 1756-L73S?
A: The 1756-L73S is the SIL 2-certified safety variant for use with GuardLogix safety I/O. The standard 1756-L73 is for non-safety standard control applications.
Q: Can I use the 1756-L73 without a battery?
A: Yes, with the 1756-ESMCAP or 1756-ESMNSE energy storage module installed. These capacitor-based modules maintain memory during power loss without battery replacement cycles.
Q: What firmware version should I use?
A: Match firmware to your Studio 5000 / RSLogix 5000 version. Firmware v30+ is recommended for new projects. Konmask can supply units at specific firmware versions upon request.
Q: Is this unit suitable for redundant controller configurations?
A: Yes. Pair two 1756-L73 controllers with a 1756-RM2/A redundancy module in separate chassis for hot-standby redundancy. Both controllers must run identical firmware and program revisions.
Q: What is the warranty on surplus units?
A: Konmask provides a 90-day functional warranty on all tested surplus units. New sealed units carry the original Rockwell Automation warranty terms.
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