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Aaron Bloom | Support Engineer
Welcome to the series designed to help you improve your commissioning of ABB’s ACH580. This Tech Tip covers the ‘checksum’ feature that is helpful in a few ways. You can confirm if the drives parameters have been changed away from the commissioned set, prevent a tampered parameter set from running the drive that could cause damage to the motor/process, and verify if a particular drive conforms to your standard parameter configuration for that application.
Before we jump into setting up the checksum, we should understand what it is, and how it works. The checksum is generated by applying a mathematical equation to the value of all the parameters that make up the checksum. This allows the parameters settings to be represented by a single number in a way that if any of the respective parameters are changed the checksum will change. The ACH580 offers two separate checksums; A and B. The difference between the two is checksum B does not include any fieldbus, energy and motor data which makes it perfect for having the checksum pre-set as part of application templates.
Once configured the drive will compare the actual checksum against the approved checksum and preform an action based on the Checksum action parameter.
Now let’s jump into configuring the check sum feature on the ACH580 in 4 easy steps.
Step 1. Set up the drive as required for your application and commission the drive.
Step 2. Save the current checksum to the approved checksum to compare against by setting bit 12 (checksum A) or 13 (checksum B) in the Checksum Control Word parameter 96.55 to 1. This will copy the actual checksum into the approved checksum parameter and then reset the bit to 0.
Step 3. Set the action of the drive once there is a checksum mismatch by adjusting Checksum action parameter 96.54, Prue Event or Warning will log the mismatch in the drives internal log but will not hinder operation while Warning and prevent start and Fault will prevent the drive from running until the checksum matches again or the checksum is disabled.
Step 4. The Last step is to enable the comparison between the approved checksum and the actual checksum this is done by setting bit 8 (checksum A) or bit 9 (checksum B) of the Checksum control word parameter 96.55 to 1. Note this should be the same checksum that you set in Step 2.