Allen-Bradley PowerFlex HIM Modules: 20-HIM-A6

Technical Dossier

Product Details And Specifications

Allen-Bradley PowerFlex HIM Series Technical Notes

The Allen-Bradley (Rockwell Automation) PowerFlex Human Interface Module (HIM) series — designated under the 20-HIM product family — is the standard operator interface platform for PowerFlex 4, 40, 400, 70, 700, 700H, 700S, 750, and 755 variable frequency drives (VFDs). Deployed across global heavy industry sectors including petrochemical refineries, nuclear power auxiliary systems, offshore platforms, pulp and paper mills, and large-scale water treatment facilities, the 20-HIM series provides local parameter programming, real-time diagnostics, fault history retrieval, and drive-to-drive parameter copying. Its modular plug-in architecture allows field replacement without drive shutdown in most configurations, making it a critical spare parts category for facilities operating continuous-process equipment. The installed base of PowerFlex drives globally exceeds several million units, ensuring sustained demand for 20-HIM replacement modules well into the 2030s.

The Evolution of PowerFlex HIM Architecture

The 20-HIM series was introduced alongside the PowerFlex 70/700 platform in the early 2000s as a replacement for the earlier DriveExplorer-dependent programming interfaces used on legacy 1336 PLUS and 1336 IMPACT drives. The original architecture used a proprietary DPI (Drive Peripheral Interface) serial bus operating at 125 kbps, enabling daisy-chain connectivity between the HIM and other DPI-compatible peripherals such as communication adapters and I/O expansion modules.

Early variants (20-HIM-A3, 20-HIM-C3S) featured basic LCD displays with limited parameter navigation. Subsequent generations introduced full alphanumeric displays (20-HIM-A6, 20-HIM-C6S), expanded fault log capacity, and support for parameter file upload/download — a critical feature for rapid drive replacement in multi-drive installations. The 20-HIM-H6 introduced remote-mount capability via a 1-meter or 3-meter cable kit, enabling panel-door mounting without direct drive access.

With the introduction of the PowerFlex 750 and 755 series (2008–2012), Rockwell Automation migrated to the 20-HIM-A20 platform, which features a larger graphical display, USB connectivity, and compatibility with the Studio 5000 / Connected Components Workbench ecosystem. Legacy 20-HIM-A6 and 20-HIM-C6S modules are not forward-compatible with PowerFlex 750/755 drives, creating a permanent bifurcation in the spare parts supply chain. Facilities operating mixed fleets of PowerFlex 70/700 and 750/755 drives must maintain separate HIM inventories.

As of 2024, the 20-HIM-A3, 20-HIM-C3S, and several early alphanumeric variants have been officially discontinued by Rockwell Automation with no direct replacement. Long-term maintenance of these models depends entirely on the secondary market and specialist distributors.

PowerFlex 20-HIM Full Catalog & Functionalities (SKU List)

The following SKUs represent the verified production and service catalog for the Allen-Bradley PowerFlex 20-HIM Human Interface Module series. All models use the DPI bus interface unless otherwise noted.

20-HIM-A6: Full-numeric LCD HIM, panel-mount, compatible with PowerFlex 70/700/700H/700S; standard field replacement unit.
20-HIM-A3: Basic LCD HIM, limited parameter display; early-generation model, now discontinued, secondary market only.
20-HIM-C6S: Full-numeric LCD HIM with remote-mount capability via cable; panel-door installation without drive access.
20-HIM-C3S: Basic LCD remote-mount HIM; discontinued, replaced by 20-HIM-C6S in active installations.
20-HIM-H6: Hand-held HIM with 1m cable; used for portable commissioning and diagnostics across multiple drives.
20-HIM-A20: Graphical HIM for PowerFlex 750/755 series; USB port, larger display, not compatible with 70/700 platform.
20-HIM-C20S: Remote-mount graphical HIM for PowerFlex 750/755; panel-door installation, 1m or 3m cable options.
20-HIM-H20: Hand-held graphical HIM for PowerFlex 750/755; portable commissioning tool.
20-HIM-A6-RS: Refurbished/service-exchange variant of 20-HIM-A6; Rockwell-certified reconditioned unit.
20-HIM-C6S-RS: Refurbished remote-mount variant; service-exchange program unit.
20-HIM-A6-NP: 20-HIM-A6 without protective overlay; used in specific OEM panel configurations.
20-HIM-B6: Blank cover plate for DPI port; used when HIM is not installed and port must be sealed.
20-HIM-A6-1: Regional variant of 20-HIM-A6 with alternate language firmware pre-loaded.
20-HIM-A20-1: Regional/language variant of 20-HIM-A20 for non-English market deployments.
20-HIM-C20S-1: Remote-mount graphical HIM, regional language variant for PowerFlex 755 installations.
20-HIM-H20-1: Hand-held graphical HIM, regional language variant; portable use on PowerFlex 750/755 drives.

Quality Control for the PowerFlex 20-HIM Range

The 20-HIM series presents specific quality verification challenges due to its DPI bus communication dependency and firmware version sensitivity. DriveKNMS applies the following test protocol to all 20-HIM units processed through its facility:

DPI Bus Integrity Test: Each unit is connected to a live PowerFlex 70 or 700 test drive and verified for successful DPI enumeration. Units that fail to enumerate within the standard 5-second timeout are rejected.
Display Pixel Verification: Full LCD pixel map test is executed to identify dead pixels or contrast degradation — a common failure mode in aged 20-HIM-A6 units stored in high-humidity environments.
Keypad Actuation Test: All navigation and function keys are tested for consistent actuation force and electrical continuity.
Parameter Read/Write Cycle: A standardized parameter set is written to the connected drive via the HIM and read back to confirm data integrity across the DPI link.
Firmware Version Logging: Firmware revision is recorded for each unit. Customers requiring a specific firmware version for compatibility with existing drive configurations can request version-matched units.
Connector and Housing Inspection: DPI connector pins are inspected under magnification for corrosion, bent contacts, or mechanical damage. Housing latches are tested for secure engagement.