20-HIM-A6 HIM Module Replacement Guide

Overview

The Human Interface Module (HIM) is a vital diagnostic and control interface for industrial motor drives. Within the Allen-Bradley/Rockwell Automation family, the 20-HIM-A6 is a premier, full-numeric keypad, monochrome LCD operator interface module. It is primarily used with PowerFlex 7-Class and PowerFlex 750-Series AC variable frequency drives (VFDs).

In physical plant environments, HIM modules undergo continuous wear. Tactile membrane buttons wear down, LCD backlights dim, and liquid ingress can damage underlying circuit boards. When a 20-HIM-A6 fails, plant operators lose local diagnostics, drive manual control, and access to parameter configuration settings.

This technical guide provides industrial plant engineers, control system panel builders, and maintenance electricians with a complete roadmap for analyzing, replacing, and configuring a replacement 20-HIM-A6 HIM module.

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Legacy Product Information

The Allen-Bradley 20-HIM-A6 is an Enhanced IP20-rated LCD HIM module. Designed to communicate over the proprietary Drive Peripheral Interface (DPI), it serves as the primary direct-access utility for parameter programming, maintenance diagnostics, and manual manual override control (Start/Stop/Jog).

Technical Specifications

• Display Type: Monochrome, high-contrast LCD with adjustable LED backlighting.
• Display Capacity: 6 lines x 21 characters (supports full parameter text names and values).
• Keyboard Interface: Full numeric keypad (0-9) alongside direction, dynamic soft keys, and motor control keys (Start, Stop, Jog, Direction).
• Communication Protocol: DPI (Drive Peripheral Interface) serial protocol, running at 125 kbps.
• Physical Port: Proprietary rear 20-pin DPI male alignment header and a supplemental RJ45-type terminal socket block for remote cable installation.
• Environmental Sealing: IP20 (NEMA Type 1) when handheld or directly integrated into the drive's native front faceplate; upgradable to IP66 (NEMA Type 4X/12) when configured with a sealed, panel-mount bezel.

Common Uses & Applications

• Parameter Backups: Storing configurations locally on the module using the built-in "Copycat" utility.
• Commissioning: Fast-track start-up wizards on the PowerFlex 753 and 755 series.
• Local Control Stations: Mounted on physical Motor Control Center (MCC) enclosure doors using dedicated remote-mount patch assembly kits.

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Recommended Replacements

If your facility is replacing a legacy, malfunctioning, or unreadable 20-HIM-A6, you have several replacement pathways dependent on your cabinet layout and integration requirements.

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Compatibility Considerations

Before replacing your existing HIM module, verify environmental, electrical, and physical system configurations to avoid diagnostic failures or hardware damage.

Physical Footprint & Mounting

• Direct Drive Insertion: The 20-HIM-A6 physically slides into the native front-door cradle of PowerFlex 70, 700-Series, and 750-Series (753 and 755) drives. The modular snap-fit retention tabs align with structural chassis alignment rails on the VFD’s power module housing.
• Remote Cutouts: If upgrading to a door-mount setup, the 20-HIM-C6S style option requires a standard 22.5 mm or 50 mm circular knockout hole on the enclosure panel face, bound tightly by structural retaining nuts on the back of the bezel assembly.

Electrical & Communication Wiring (Caution on RJ45 Port)

• DPI Pinout Architecture: Though the cable interface uses a physical RJ45 connector socket, the electrical protocol is NOT Ethernet. Connecting a standard Ethernet computer card, switch, or controller directly to the HIM's RJ45 DP port or the drive's DPI connection port will cause immediate over-current damage to the digital control board.
• Cable Restrictions: Always use direct internal shielded communication cables (e.g., 20-HIM-H10 or alternative proprietary lengths up to 10 meters maximal length).
• Power Draw: The host VFD supplies 12VDC power on the DPI channel. Long cable lengths can cause localized voltage drop. Do not exceed 10 meters of serial cabling without using a dedicated DPI breakout or active bus-line adapter.

Module Firmware Compatibility

The standard 20-HIM-A6 has gone through several internal firmware generations (Series A through Series C). Ensure your HIM firmware is compatible with your VFD’s main firmware. For example, PowerFlex 755 drives with v14.0 or newer firmware may not fully support original v2.x 20-HIM-A6 series modules—meaning some parameters may read as "Unknown Parameter" or "Database Error." Updating the HIM module using the Rockwell ControlFLASH utility preserves total system compatibility.

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Upgrade Benefits

Firms transitioning from older interfaces can expect immediate performance gains upon deploying a fresh 20-HIM-A6:

• Drastically Reduced Programming Time: Technicians can write parameter numbers and scaling values directly with the integrated 10-key numeric layout, eliminating tedious scrolling.
• Advanced Multi-line Display: The 6-line LCD shows clear contextual diagnostic lines, preventing the need to reference paper code manuals.
• Multi-language Pack Integration: Features full-text parameters readable in English, Spanish, French, German, Italian, Portuguese, and Simplified Chinese.
• Copycat Data Protection: Stores up to five individual drive parameter sets in non-volatile memory, allowing maintenance teams to instantly clone settings onto hot-swapped spare drives.

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Common Migration Challenges

Avoid standard operational issues by preparing for these typical technical challenges:

1. The "DPI Port Loss" Fault (F081 / F082 / F083): When a default-configured drive loses touch with a physical dynamic control device like the HIM, it triggers a security shut-down. To prevent this, temporary maintenance changes or backup adjustments must be bypassed by temporarily setting the VFD’s DPI Loss Action parameter to "Ignore" or "Stop" while performing hot-swaps.
2. Missing Copycat Files: Older HIM versions do not support modern drive formats. If you try to restore system files from a different series, parameter tables can get scrambled. Secure exact device firmware version maps prior to rewriting VFD profiles.
3. Corroded or Bent Connecting Pins: Moisture and vibration on a direct-mount setup can damage the alignment pins on the back of the module. Inspect existing connector sockets inside the host drive bay for alignment before forcing a new unit in.

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Step-by-Step Replacement Procedure

Follow these steps to safely complete the physical swap:

Step 1: Back Up Existing Parameters (If Possible)

1. Mount the old 20-HIM-A6 module into the drive cradle.
2. Power up the input line safely.
3. Use the dynamic folder controls to navigate to HIM Memory / Copycat.
4. Select Device to HIM and copy the drive parameters (as well as option modules, e.g., dual-port Ethernet cards) directly onto the HIM.
5. Safely power down the VFD.

Step 2: Establish True LOTO (Lockout / Tagout)

1. Turn off, tag, and lock out the primary AC supply breaker sourcing the PowerFlex Drive.
2. Mandatory Safety Waiting Window: Wait at least 5 to 15 minutes (correlate with your drive manual's capacitor discharge instruction plate) for power bus capacitors to drop below 50VDC. Verify safe voltages using an insulated digital multimeter on the DC+ and DC- terminals.

Step 3: Remove the Faulty Module

1. For drive-mounted models, push the localized lock-release latches positioned on the top and bottom edge borders.
2. Pull the module horizontally forward and straight out of the drive’s recessed physical bay.
3. For panels with remote bezel cabling, loosen the rear bracket assembly collar, slide out the interface board, and gently press the security tab to unplug the RJ45 DPI interface wire.

       [Drive Cradle / Face]
   =============================
  |   _______________________   |
  |  |                       |  |
  |  |  [Push Release Latch] |  |   <-- Depress top latch
  |  |                       |  |
  |  |  ( 20-HIM-A6 Module ) |  |   <-- Pull straight out
  |  |                       |  |
  |  |  [Push Release Latch] |  |   <-- Depress bottom latch
  |  |_______________________|  |
  |                             |
   =============================

Step 4: Physical Installation

1. Inspect the back pins of the replacement 20-HIM-A6 for alignment.
2. Slide the replacement module directly into the physical mounting guides on your power board frame.
3. Push firmly until the lock clip snaps securely into position.
4. For remote doors, connect the shielded RJ45 cord, snap the unit into the bezel base, and tighten the seal ring to IP66 specs.

Step 5: Power-on Testing and Diagnostics

1. Safely remove lockout tags and re-apply input power.
2. Watch the replacement display start and initialize its boot cycle. Under normal conditions, the screen will illuminate, configure standard communication channels, and display real-time drive feedback (e.g., Output Freq, Motor Amps, etc.).
3. If necessary, navigate to the HIM Memory / Copycat menu, select HIM to Device, and download your stored backup configuration back to the drive.

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Frequently Asked Questions

Q1: Can I hot-swap the 20-HIM-A6 while the motor is running?

Answer: The standard DPI communication design supports hot-swapping. However, do not do this without checking your drive parameters first. If parameter Logic Mask or your active start/stop references rely directly on the physical HIM, disconnecting it will cause a fault (like F081 DPI Port Loss). To avoid this, shift dynamic control to a secondary network card (e.g., EtherNet/IP) before removing the display.

Q2: Why does my physical display show "Database Error" or "Unsupported Dev"?

Answer: This indicates that the firmware on your replacement HIM is older than the drive firmware. The module cannot parse the drive's parameter structure. To resolve this, flash the 20-HIM-A6 to the latest firmware library using Rockwell's ControlFLASH software and a 1203-USB converter cable.

Q3: What is the maximum cable run length for a remote-mounted 20-HIM-A6?

Answer: The absolute maximum rated physical length using standard passive DPI cables is 10 meters (32.8 feet). Exceeding this length will cause communication timeouts and dropouts due to signaling degradation and voltage drop on the 12VDC power lines.

Q4: Can I use standard Ethernet cables for a panel mounting run?

Answer: No. Standard Ethernet cables often lack the heavy shielding required to protect the differential serial lines of the DPI protocol from electrical noise inside motor control cabinets. Also, standard Ethernet PIN assignments vary; using a miswired cable can short-circuit the 12VDC power lines on the DPI network, damaging the drive's control board. Always use heavy-shielded Allen-Bradley DPI cables (e.g., 20-HIM-H10 or 20-HIM-H30).

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Related Products & Families

• PowerFlex 70 / 700 / 700S series AC Drive chassis.
• PowerFlex 753 / 755 standard modular VFD components.
• 1203-USB Communication Module (USB to DPI converter).
• 20-HIM-H10 (Premium 3-meter remote IP66 cable setup).
• 20-XBI-DPI-2CV (Splitter cables and multi-drive system parts).

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Need Help?

At Palm Parts Solution, we keep North American industrial plants running by providing prompt, reliable access to critical automation components. Whether your team requires a brand-new, premium refurbished, or high-quality surplus Allen-Bradley 20-HIM-A6 module, our team is here to help. All of our replacement modules undergo rigorous diagnostic and physical testing to ensure reliable operation and are backed by a comprehensive warranty to minimize unexpected downtime. Contact our regional support team today to secure your replacement HIM parts.