Description
Product Introduction
The Allen-Bradley 1756-A13 is a 13-slot ControlLogix chassis designed to house ControlLogix processors, communication modules, and I/O modules. The chassis provides the physical mounting structure and backplane communication path required for a ControlLogix automation system.
In our field experience, the chassis is often overlooked during system troubleshooting because it has no program logic or configuration file. However, a damaged backplane connector, incorrect power supply sizing, or poor installation can create faults that appear to be caused by individual I/O modules. The 1756-A13 remains widely used in large ControlLogix cabinets where additional slot capacity is needed.
Key Technical Specifications
| Parameter | Value |
|---|---|
| Manufacturer | Allen-Bradley / Rockwell Automation |
| Catalog Number | 1756-A13 |
| Product Family | ControlLogix |
| Module Type | Standard Chassis |
| Number of Slots | 13 Slots |
| Mounting Orientation | Horizontal Panel Mount |
| Backplane Voltage | 1.2 VDC / 3.3 VDC / 5.1 VDC / 24 VDC |
| Maximum Backplane Current (1.2V) | 1.5 A |
| Maximum Backplane Current (3.3V) | 4 A |
| Maximum Backplane Current (5.1V) | 15 A chassis / 6 A per slot |
| Maximum Backplane Current (24V) | 2.8 A |
| Maximum Power Dissipation | 5.4 W |
| Minimum Cabinet Size | 24 × 30 × 8 in. (60.9 × 76.2 × 20.3 cm) |
| Operating Temperature | 0°C to +60°C |
| Storage Temperature | -40°C to +85°C |
| Enclosure Type | Open-style |
| Mounting Method | Panel Mount |
| Slot Type | ControlLogix Module Slots |
| Lifecycle Status | Active |
Application Scenarios & The “Trench” Experience
A production line stops.
The processor is healthy. The communication modules are online. Engineers swap I/O cards, replace power supplies, and still see intermittent module faults.
Then someone checks the chassis.
A loose backplane connection or damaged slot can create symptoms that look exactly like a failed controller or communication card.
The chassis is the foundation of the ControlLogix system. When it fails, every module sitting on it becomes suspect.
Typical applications include:
- Automotive Manufacturing – Large assembly cells – The 13-slot chassis provides space for processors, EtherNet/IP communication modules, motion modules, and distributed I/O interfaces.
- Process Industries – Continuous control systems – Used where multiple analog, communication, and specialty modules share one ControlLogix rack.
- Power Generation – Auxiliary control systems – Provides rack space for redundant controllers, communication interfaces, and monitoring modules.
- Water & Wastewater – Treatment plant automation – Supports large I/O configurations requiring multiple ControlLogix modules.
- OEM Machinery – Large machine platforms – Allows builders to standardize on a single ControlLogix hardware architecture.
Field Case
A chemical processing facility reported random controller communication faults after replacing several ControlLogix modules.
The modules tested correctly on a bench rack.
The issue was eventually traced to one damaged chassis slot. The backplane connection intermittently failed when vibration from nearby equipment transferred into the cabinet.
Replacing the 1756-A13 chassis restored stable operation.
The important lesson: not every ControlLogix fault belongs to the processor.
- 1756-A13
- 1756-A13
Transparency SOP: Quality Assurance & Testing
We don’t just ship boxes; we inspect them as part of an actual ControlLogix system.
- Inbound Inspection
- Verify Allen-Bradley catalog number and chassis identification.
- Inspect backplane connector pins and slot guides.
- Check mounting tabs, housing condition, and physical damage.
- Live Rack Testing
- Install ControlLogix modules into multiple chassis slots.
- Verify backplane communication.
- Confirm module recognition through Studio 5000 Logix Designer.
- Electrical Parameter Checks
- Verify backplane power distribution.
- Check slot communication stability.
- Confirm no abnormal resistance or damaged contacts.
- Hardware Verification
- Record chassis series and revision.
- Confirm compatibility with installed ControlLogix modules.
- Verify power supply requirements.
- Final QC & Anti-static Packaging
- Clean connectors.
- Protect backplane contacts from contamination.
- Package using anti-static protection.
The Veteran’s Tech Trap Guide
⚠️ Do not mount the chassis vertically unless the OEM documentation specifically allows it. The 1756-A13 is designed for horizontal installation. Heat dissipation and module spacing depend on correct orientation.
⚠️ Check power supply capacity before filling all slots. A 13-slot chassis does not mean every combination of modules can be installed without checking backplane current consumption.
❗ Inspect unused slots. Empty slots require proper slot fillers where applicable. Dust, metal particles, and accidental contact can create long-term reliability problems.
⚠️ Do not assume a module fault means the module is bad. If multiple cards show intermittent faults, inspect the chassis backplane first.
⚠️ Verify chassis series compatibility during upgrades. Older and newer ControlLogix hardware combinations may require attention to power supply and module compatibility.
Take photos of the rack layout before removing anything. Slot order matters when troubleshooting large ControlLogix systems.
Frequently Asked Questions (FAQ)
Q1. What is the Allen-Bradley 1756-A13?
The 1756-A13 is a 13-slot ControlLogix chassis used to mount ControlLogix processors, communication modules, and I/O modules while providing the internal backplane communication bus.
Q2. How many modules can the 1756-A13 hold?
The chassis provides 13 ControlLogix module slots. The actual usable configuration depends on power supply capacity and module current requirements.
Q3. Does the 1756-A13 include a power supply?
No. The chassis does not include a power supply. A compatible ControlLogix power supply, such as a 1756-PA or 1756-PB series unit, must be selected separately based on the system load.
Q4. Can I replace a smaller chassis with the 1756-A13?
Usually yes, if the cabinet space, power budget, and Studio 5000 project configuration support the change. The controller does not care about the physical slot count alone; the complete chassis configuration must match the application.
Q5. Is the 1756-A13 still manufactured?
Yes. Rockwell Automation lists the 1756-A13 ControlLogix 13 Slot Chassis as an active product.
Q6. Can the chassis be hot-swapped?
No. The chassis is a mechanical and electrical foundation for the ControlLogix system. Remove power before replacing it. Moving modules between chassis requires proper shutdown procedures.
Q7. Why would a surplus 1756-A13 be cheaper than a direct OEM purchase?
Industrial surplus pricing usually reflects sourcing channels such as excess plant inventory, spare parts stock, and equipment retirement programs. The key factor is inspection history and functional verification.
Q8. What warranty is typically provided?
Qualified automation suppliers commonly provide a 12-month warranty on tested new surplus and refurbished 1756-A13 chassis units. Warranty terms should always be confirmed before purchase.
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