Allen-Bradley 1756-A4K Chassis, 4 Slot, Conformally Coated
$1,404.99
Out of stock
Request QuoteAllen-Bradley 1756-A4K — The Allen-Bradley 1756-A4K is a conformally-coated 4-slot ControlLogix chassis (Bulletin 1756, Series B/C). It houses up to 4 Bulletin 1756 I/O modules, controllers, power supplies, and communication modules on a high-speed backplane, with horizontal back-panel mounting required for proper airflow. The K-suffix conformal coating applies a protective polymer film to the printed circuit board for enhanced resistance to humidity, salt spray, dust, and mildly corrosive atmospheres (wash-down, marine, oil-and-gas, pulp-and-paper, chemical). Electrical and mechanical specifications are identical to the base 1756-A4 chassis. Pairs with any standard 1756-PA/PB power supply or redundant 1756-PA75R/PB75R redundant supply configuration.
| Product Family | Bulletin 1756 ControlLogix Chassis (conformal coated) |
| Slot Count | 4 |
| Conformal Coating | Yes (K suffix) — for harsh environments |
| Backplane Current (5.1V DC) | 15 A chassis / 6 A per slot |
| Backplane Current (24V DC) | 2.8 A chassis / 2.8 A per slot |
| Operating Temperature (Series C) | -25…+60 °C (-13…+140 °F) |
| Mounting | Horizontal back-panel only |
Description
Allen-Bradley 1756-A4K
The Allen-Bradley 1756-A4K is a conformally-coated 4-slot ControlLogix chassis (Bulletin 1756, Series B/C). It houses up to 4 Bulletin 1756 I/O modules, controllers, power supplies, and communication modules on a high-speed backplane, with horizontal back-panel mounting required for proper airflow. The K-suffix conformal coating applies a protective polymer film to the printed circuit board for enhanced resistance to humidity, salt spray, dust, and mildly corrosive atmospheres (wash-down, marine, oil-and-gas, pulp-and-paper, chemical). Electrical and mechanical specifications are identical to the base 1756-A4 chassis. Pairs with any standard 1756-PA/PB power supply or redundant 1756-PA75R/PB75R redundant supply configuration.
| Chassis Overview | |
|---|---|
| Catalog Number | 1756-A4K |
| Product Family | Bulletin 1756 ControlLogix Chassis |
| Slot Count | 4 |
| Base (Non-Coated) Counterpart | 1756-A4 |
| Mounting Orientation | Horizontal back-panel only |
| Enclosure Type Rating | None (open-style) — install in appropriate NEMA enclosure |
| Backplane Electrical | |
|---|---|
| Backplane Current (Max @ 1.2V DC) | 1.5 A chassis |
| Backplane Current (Max @ 3.3V DC) | 4 A chassis / 4 A per slot |
| Backplane Current (Max @ 5.1V DC) | 15 A chassis / 6 A per slot |
| Backplane Current (Max @ 24V DC) | 2.8 A chassis / 2.8 A per slot |
| Isolation Voltage | Determined by installed power supply and modules |
| Physical / Mechanical | |
|---|---|
| Width (with Standard Power Supply) | 26.26 cm (10.34 in.) |
| Width (with Slim Power Supply) | 23.01 cm (9.06 in.) |
| Height | 15.8 cm (6.22 in.) |
| Depth | 16.9 cm (6.65 in.) |
| Wire Size — Functional Earth | 8.3 mm² (8 AWG) solid or stranded copper, 90 °C+ |
| Wire Size — Protective Earth | 2.1 mm² (14 AWG) solid or stranded copper, 90 °C+ |
| Environmental | |
|---|---|
| Operating Temperature (Series C) | -25…+60 °C (-13…+140 °F) |
| Surrounding Air Temperature (Max) | 60 °C (140 °F) |
| Conformal Coating Benefits | Humidity, salt spray, dust, mildly corrosive atmosphere protection (marine, wash-down, chemical, pulp-and-paper, oil-and-gas) |
| Hazardous-Location Temperature Code (NA) | T4 |
| IECEx Temperature Code | T4 |
| Power Supply Compatibility | |
|---|---|
| Standard AC | 1756-PA72, 1756-PA75, 1756-PA30XT / PA50K / PA72K / PA75K (conformal-coated) |
| Standard DC | 1756-PB72, 1756-PB75, 1756-PB30XT / PB50K / PB72K / PB75K (conformal-coated) |
| Redundant AC | 1756-PA75R / 1756-PA75RK (conformal-coated redundant) |
| Redundant DC | 1756-PB75R / 1756-PB75RK (conformal-coated redundant) |
| Redundant Chassis Adapter | 1756-PSCA2 / 1756-PSCA2K (conformal-coated) |
| ControlLogix 5580 / 5570 Platform Features | |
|---|---|
| Chassis Form Factor | Chassis-based modular architecture (4, 7, 10, 13, or 17 slots) |
| Controller Compatibility | ControlLogix 5580 (L8/L85E), 5570 (L7x), 5560 (L6x), 5550 (L55) |
| Network Interface | EtherNet/IP (1756-EN2TR, EN2TRK, EN3TR, EN4TR), ControlNet, DeviceNet, USB |
| Removal & Insertion Under Power (RIUP) | All 1756 modules support RIUP without removing chassis power |
| Redundancy Support | Controller / chassis redundancy via 1756-RM2/RMXT redundancy modules and dual-attached 1756-EN2TR/RXT adapters |
| Safety Support | GuardLogix 5580/5570 safety controllers; SIL 3 / PLe safety I/O via 1756-IB16S, -OB16S, -L8xS modules |
| Conformal Coating Option | "K" suffix — IPC-CC-830 Class 3 conformal coating for harsh environments |
| XT Extended Temperature | "XT" suffix — -25…+70 °C operating range for outdoor / unconditioned enclosures |
| Studio 5000 Integration | Native Add-On Profiles (AOPs) in Studio 5000 Logix Designer; Auto-discover on EtherNet/IP networks |
| Environmental Specifications | |
|---|---|
| Operating Temperature | 0…+60 °C (32…+140 °F) — standard industrial range per IEC 61131-2 |
| Storage Temperature | -40…+85 °C (-40…+185 °F) |
| Relative Humidity | 5…95% non-condensing per IEC 60068-2-30 |
| Vibration (Operating) | 2 g @ 10…500 Hz per IEC 60068-2-6 (Test Fc) |
| Shock (Operating) | 30 g per IEC 60068-2-27 (Test Ea) |
| Shock (Non-operating) | 50 g per IEC 60068-2-27 |
| ESD Immunity | 6 kV contact / 8 kV air discharge per IEC 61000-4-2 |
| Radiated RF Immunity | 10V/m, 80…6000 MHz per IEC 61000-4-3 |
| EFT / Burst Immunity | ±4 kV @ 5 kHz on power ports; ±2 kV @ 5 kHz on signal ports per IEC 61000-4-4 |
| Surge Transient Immunity | ±1 kV line-line, ±2 kV line-earth per IEC 61000-4-5 |
| Conducted RF Immunity | 10V rms, 150 kHz…80 MHz per IEC 61000-4-6 |
| Emissions | CISPR 11 Group 1 Class A; IEC 61000-6-4 (industrial environment) |
| Pollution Degree | 2 (standard industrial) |
| Enclosure Type Rating | None (open-style) — install in a suitable industrial enclosure (IP54/NEMA 12 or better) |
| Certifications & Standards | |
|---|---|
| c-UL-us (UL Listed) | UL Listed Industrial Control Equipment for US and Canada |
| c-UL-us (Hazardous Locations) | UL Listed for Class I Division 2, Group A/B/C/D (where module-certified) |
| CE Marked — EMC Directive | 2014/30/EU — EN 61326-1, EN 61000-6-2, EN 61000-6-4, EN 61131-2 |
| CE Marked — Low Voltage Directive | 2014/35/EU — EN 61131-2 (Programmable Controllers Clause 11) |
| CE Marked — RoHS Directive | 2011/65/EU — EN IEC 63000 |
| UKCA Conformity Assessment | UK Statutory Instrument 2016 No. 1091 (EMC), No. 1101 (LVD), 2012 No. 3032 (RoHS) |
| ATEX (Explosive Atmospheres) | 2014/34/EU — EN IEC 60079-0, EN IEC 60079-7 Protection "e" II 3G Ex ec IIC T4 Gc (where module-certified) |
| IECEx | IEC 60079-0, IEC 60079-7 Protection "e" II 3G Ex ec IIC T4 Gc (where module-certified) |
| RCM (Australia) | Australian Radiocommunications Act — AS/NZS CISPR 11, Industrial Emissions |
| KC (Korea) | Korean Registration of Broadcasting and Communications Equipment |
| Morocco | Arrêté ministériel n° 6404-15 |
| CCC (China) | CNCA-C23-01 Explosion-Proof Electrical Products (where applicable) |
Related Technical Topics
- Chassis Slot Population Rules — The 1756 chassis can populate all slots without reserving an empty slot adjacent to the power supply on modern (5580/5570) controllers. Legacy 5550 systems should respect the heat-dissipation spacing recommendation in 1756-IN101. Max module count = chassis size; do not span chassis with backplane-crossing modules without an 1756-EN2TR or equivalent.
- Power Supply Sizing — Total 5V DC backplane current drawn by all installed modules must not exceed the power supply rating (1756-PA72/PA75/PA75R/PB72/PB75/PB75R, etc.). Consult 1756-TD001 and each module’s datasheet for per-module current. Derate by 10% for redundant-supply applications.
- EtherNet/IP Ring (DLR) Configuration — Dual-port modules (EN2TR, EN2TRK, EN3TR, EN4TR) support Device Level Ring (DLR) topology. Configure one controller or switch as the Ring Supervisor; remaining nodes operate as participants. DLR provides single-fault tolerance with sub-3 ms recovery time.
- Firmware Revision Compatibility — When replacing a module, match the firmware revision of the replacement to the original controller’s expected FW. Studio 5000 AOPs surface firmware mismatch warnings; use ControlFLASH to upgrade a replacement module before commissioning.
Source: Module-specific specifications are compiled from Rockwell Automation Publication 1756-TD002Q-EN-P — ControlLogix 5580 / 5570 Technical Data (April 2025) together with the module’s individual product specification sheet. Platform features describe the ControlLogix 5580 / 5570 architecture; environmental specifications reflect the standard industrial operating envelope per IEC 61131-2; certifications listed are the standard Allen-Bradley marking stack — consult the module-specific datasheet for certification file numbers. Rockwell Automation Publication 1756-IN621B-EN-P, March 2017 — ControlLogix Chassis Installation Instructions.
Disclaimer: PLC Exchange is an independent reseller and is not an authorized distributor, affiliate, licensee, partner, or agent of Allen-Bradley / Rockwell Automation. All product information on this page is compiled from publicly-available manufacturer publications, technical data sheets, and catalog sources, each of which remains the copyright of its originating manufacturer. We make no representation or warranty, express or implied, regarding the accuracy, completeness, timeliness, or fitness for any particular purpose of the specifications or descriptions shown — content may contain errors, omissions, or out-of-date information. Product images are the property of their respective manufacturers, trademark owners, and source publications, and are displayed solely for identification purposes under the nominative fair use doctrine; images are representative and may depict a different configuration or catalog variant than the exact product listed. Purchasers should independently verify specifications against the current manufacturer publication before placing an order. All product names, trademarks, service marks, and registered trademarks are the property of their respective owners, and their use does not imply endorsement or affiliation.
Technical Notes for 1756-A4K
- Refer to the manufacturer's installation instructions for proper mounting, wiring, and configuration.
- Ensure compatibility with your existing system architecture before ordering.
- All 1756-A4K units sold by PLC Exchange are tested and ship in original factory packaging.
- For application-specific questions or system compatibility verification, contact PLC Exchange technical support at [email protected] or 980-202-0882.
Alternative Part Numbers & Names for 1756-A4K
The 1756-A4K by Allen-Bradley may also be found under the following alternative names, catalog numbers, or common search variations:
- 1756A4K
- Allen Bradley 1756-A4K
- Allen-Bradley 1756-A4K
- 1756 A4K
- 1756/A4K
All variations refer to the same Allen-Bradley product. If you are unsure whether this is the correct part for your application, contact our team for assistance.
Additional information
| Weight | 0.5 lbs |
|---|---|
| Dimensions | 10.3 × 6.2 × 6.7 in |
| warranty | 2.5 Year PLC Exchange Warranty, 30 Days worry-free return from delivery |
| upc | 885630569512 |
| mpn | 1756-A4K |
| manufacturer | Allen-Bradley |
| condition | Original Packaging |
Dimensions & Weight for 1756-A4K
| Shipping Dimensions | |
|---|---|
| Weight | 0.5 lbs |
| Length | 10.3 in |
| Width | 6.2 in |
| Height | 6.7 in |
| Box Dimensions (L×W×H) | 10.3 × 6.2 × 6.7 in |
Dimensions shown are for the shipping package. For module-level mechanical dimensions, refer to the manufacturer datasheet.
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Frequently Asked Questions
Where can I find the technical datasheet for the 1756-A4K?
The official manufacturer datasheet is available for download on the 1756-A4K product page at PLC Exchange. Look for the Tech Data PDF link in the product description.
Does the 1756-A4K include a warranty?
Yes. Every 1756-A4K sold by PLC Exchange includes a 2.5-year warranty (30 months, full replacement). Details: https://plcexchange.net/warranty-information/
What is the return policy for the 1756-A4K?
PLC Exchange offers a 30-day worry-free return policy. Eligibility and details: https://plcexchange.net/return-policy/
When will my 1756-A4K ship?
In-stock orders placed before 4 PM ET ship the same business day via free UPS Ground. Expedited options (Next Day Air, 2nd Day Air) are available at checkout.
Who manufactures the 1756-A4K?
The 1756-A4K is manufactured by Allen-Bradley. PLC Exchange is an independent reseller specializing in Allen-Bradley industrial automation products.
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