The VLT Control Cards series serves as the primary logic and coordination component inside several drive families, covering HVAC Drive FC 102, Refrigeration Drive FC 103, AQUA Drive FC 202, AutomationDrive FC 301/302, and Lift Drive LD 302 units.
Each card governs the drive’s control processes, communication links, and operational sequencing, forming the link between input signals and the drive’s power electronics. Two main generations exist—MKI and MKII. The MKII version is backward-compatible with earlier drives provided the installed firmware is version 5.21 or higher. This compatibility reduces the need for full system replacements in many cases, allowing a control card update to extend the service life of older equipment. In installations using custom or brand-specific firmware, MKI cards may still be necessary to match the programmed feature set. Replacement procedures require strict adherence to discharge times for the drive’s DC-link capacitors. These capacitors can remain charged well after the main supply is disconnected. The exact discharge period depends on voltage class and power rating, but for larger drives it can extend to several minutes. Verifying that residual voltage is at a safe level before removing or inserting a control card is critical to avoid component damage or injury. Across the series, the layout, connectors, and mounting points follow consistent design principles, allowing similar handling across different drive types. This uniformity simplifies stocking and reduces training requirements for service personnel.
