If the speed of the VFD on remote mode is not matching the expected speed (assuming all other factors are okay, drive parameters, encoders, etc), then you can calibrate the speed command communicated through profibus for this particular drive on ICW.

Steps:

- The first thing you need is to get the actual speed (in FPM) at 60Hz using tachometer. Controls/Maintenance personnel need to put the drive on manual control and raise the frequency to 60Hz using the keypad on the drive, then tach the belt and record the speed.

- On ICW, find the drive ID from Variable Frequency Drives. You could also search for it in debugger if you know what controller the drive is run by.

Will use DR31010 as an example, ID 3. The measured speed on site is 669 at 60Hz.

- Locate the drive info on debugger. use the screenshot below as a guideline.

- Scroll down until you find "PFB_DRIVE_SPEED SpeedAt60Hz" and "PFB_DRIVE_SPEED SpeedMax" taps

- Expand "PFB_DRIVE_SPEED SpeedAt60Hz" and enter the speed value measured on site at 60Hz (669FPM for this example)

- Expand "PFB_DRIVE_SPEED SpeedMax". Calculate a new value for "ValueFPM" Under SpeedMax. Use the following equation:

(10,000 * MeasuredSpeedAt60Hz) / 8333 = SpeedMax.Value.FPM

For this example:

(10,000 * 669) / 8333 = ~802

NOTE: For this to take effect immediately, change the value on SpeedProgramFPM to any arbitrary value then back to original value. This will cause the software to recalculate the bytes of data.

- Now, you can force the drive to certain speed and ask site to measure using tachometer. The speed should match or at least be closer to the commanded value. For further adjustments, you can increase or decrease SpeedMax.ValueFPM by few integers. Higher number will decrease the speed, lower numbers will increase the speed. Do this until the speed commanded is matching the speed measured on site. Make sure site is using an accurate tachometer.