ABB ACS560 Fault 5093 Rating ID Mismatch

Getting Fault 5093 on your ABB ACS560 VFD? Learn why this identity mismatch happens after firmware updates or board replacements and how to clear the error fast.

 

If you are working with an ABB ACS560 drive and the control panel suddenly displays Fault 5093: Rating ID mismatch, you have encountered what technicians call an "identity crisis." This isn't a hardware failure like a short circuit, but rather a digital disagreement between the drive's brain and its body.

In this guide, we will explain why this fault occurs—usually after a repair or update—and the simple sequence required to get your motor spinning again.

What is the "Rating ID"?

Think of the Rating ID as the drive's DNA. It stores critical information about the drive’s physical capacity, including:

• Voltage rating (e.g., 400V)
• Current capacity (Amperage)
• Frame size (e.g., R1, R2, etc.)

This data is stored in the ZMU Memory Unit. When the drive boots up, the Control Unit compares the ID on the memory unit with the physical Power Card it is connected to. If they don’t match perfectly, the drive trips Fault 5093 to prevent you from accidentally running a motor with the wrong power settings.

Common Causes of Fault 5093

This fault is almost always triggered by a change in the drive’s internal components or software:

• Firmware Updates: Sometimes a major update requires the drive to re-verify its hardware identity.
• Replacing the Memory Unit (ZMU): Installing a new or different memory unit into the control board.
• Swapping the Control Card: If you put a new control board on an old power module.
• Replacing the Power Card: Replacing the "muscle" of the drive while keeping the old "brain."

Technician's Note: This fault is a safety feature. It ensures the software doesn't try to pull 100 Amps from a drive that is physically only rated for 50 Amps.

Step-by-Step Solution

Step 1: Reset the Fault

Before pulling out any tools, try a basic software reset.

• Press the [Reset] button on the Assistant Control Panel.
• In some cases, if the mismatch was a temporary communication glitch during boot-up, the fault will clear immediately.

Step 2: The "Cold Boot" Restart

If a reset doesn't work, the drive needs a full power cycle to re-scan the hardware components.

1. Turn off the main AC power supply to the drive.
2. Wait for the display to go completely blank. You must wait at least 2–5 minutes for the internal DC bus capacitors to discharge fully.
3. Once all LEDs are off, restore power to the drive.

Step 3: The "Double Restart" Secret

Experienced ABB field engineers know that after a board replacement, the ACS560 often requires two consecutive restarts.

• The first time you power on, the drive identifies the mismatch and "prepares" to update.
• The second power cycle actually writes the new hardware signature into the memory unit. If the fault persists after one restart, try a second one.

Summary Troubleshooting Checklist

Action Item	Why it works
Manual Reset	Clears temporary logic errors in the buffer.
Full Power Cycle	Forces the Control Unit to re-read the Rating ID from the ZMU.
Check ZMU Seating	Ensure the memory unit is pushed firmly into the slot.
Repeat Restart	Ensures the hardware Discovery process completes fully.

When is it a Hardware Problem?

If you have performed multiple cold restarts and Fault 5093 will not clear, you may have an incompatible component. For example, if you installed a ZMU memory unit from a different frame size or voltage class, the drive will never accept the ID. In this case, you must ensure the ZMU part number matches your specific drive model.