1756-ESMCAPK | Allen-Bradley ControlLogix Energy Storage Module-CAP

Product Summary

The Allen-Bradley 1756-ESMCAPK is a Capacitor Energy Storage Module (ESM) with conformal coating for the ControlLogix 5570 controller platform. It provides backup power to retain volatile memory and WallClockTime during power loss, replacing traditional lithium batteries. The -K suffix denotes the conformal coated version for enhanced moisture and contaminant protection in harsh industrial environments. It is removable and ships installed with every 1756-L7x controller.

Core Specifications

• Model Number: 1756-ESMCAPK
• Type: Capacitor Energy Storage Module (ESM) with Conformal Coating
• Function: Retains controller RAM and WallClockTime during power loss
• Removability: Removable (field-replaceable)
• Current Draw: 330 mA at 5 VDC
• Temperature Rating: 0°C to 60°C (32°F to 140°F)
• Dimensions: 17.653 × 12.7 × 7.62 cm
• Weight: 0.147 kg
• Enclosure: Open-style
• Manufacturer: Allen-Bradley by Rockwell Automation

Electrical & Functional Characteristics

• Energy Storage: Capacitor-based (no battery required)
• Residual Energy: Drops to ≤40 µJ after at least 20 minutes of de-energization
• WallClockTime Backup: Maintains real-time clock during power outages
• RAM Retention: Preserves user program and data in volatile memory
• Transport Safety: Wait minimum 20 minutes after power-down before removing to ensure safe residual energy levels
• Status Indication: Controller display shows CHRG or ESM charging during capacitor charge cycle

System Integration & Compatibility

• Compatible Controllers: 1756-L71, 1756-L72, 1756-L73, 1756-L74, 1756-L75 ControlLogix 5570 controllers
• Installation: Pre-installed in controller; field-removable for replacement
• Related Parts:
  • 1756-ESMCAP — Standard capacitor ESM (non-conformal coated)
  • 1756-ESMCAPXT — Xtreme temperature capacitor ESM
  • 1756-ESMNSE / 1756-ESMNSEK — Removable capacitor ESM with no WallClockTime backup
  • 1756-ESMNRM / 1756-ESMNRMK — Non-removable capacitor ESM (security feature; prevents USB and SD card access)

Environmental & Operational Limits

• Operating Temperature: 0°C to 60°C (32°F to 140°F)
• Storage Temperature: -40°C to +85°C (-40°F to 185°F)
• Humidity: 5% to 95% RH, non-condensing
• Vibration: 2G, 10 to 500 Hz
• Shock: 30G operating; 50G non-operating
• Approvals: CE, CCC, Australian RCM, American Bureau of Shipping

Industrial Applications

Deployed across all ControlLogix 5570 applications in manufacturing, process control, oil & gas, water treatment, and material handling where reliable memory retention and real-time clock backup are critical during power interruptions.

Frequently Asked Questions

What does the 1756-ESMCAPK do?

It is a capacitor-based energy storage module that retains controller RAM and WallClockTime during power loss, eliminating the need for a lithium battery.

What is the difference between 1756-ESMCAP and 1756-ESMCAPK?

The 1756-ESMCAP is the standard version. The 1756-ESMCAPK has conformal coating on the circuit boards for enhanced protection against moisture, dust, and chemical contaminants in harsh environments.

Can I remove the ESM while the controller is running?

No — always power down the controller first. After power-down, wait at least 20 minutes for residual capacitor energy to dissipate to ≤40 µJ before removing the module.

How do I know when the ESM is fully charged?

The controller status display will show CHRG or ESM charging during the charge cycle. When these messages are no longer displayed, the capacitor is fully charged.

What are the related part numbers?

• 1756-ESMCAP — Standard capacitor ESM (removable)
• 1756-ESMCAPK — Conformal coated capacitor ESM (this part)
• 1756-ESMCAPXT — Xtreme temperature capacitor ESM
• 1756-ESMNSEK — Conformal coated ESM with no WallClockTime backup
• 1756-ESMNRMK — Conformal coated non-removable ESM (security version)