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Why is the ATV61/71 Drives responding slowly to speed change commands on AI1 or AI2?

Issue:
Why is my ATV61/71 responding slowly to speed change commands on AI1 or AI2?

Product Line:
Altivar 61 and 71 drives

Environment:
Altivar drives which receive their speed reference signal on AI1 or AI2 from a PLC or some other type of control panel such as refrigeration control

Cause:
Customers noticing lag between commands issued for speed changes and the drives' response to command 

Resolution:
We need to determine whether the issue resides with the reference signal, with the drive, or somewhere in between. One way to do this is by monitoring the voltage (if using AI1) or current (if using AI2) in the drive's I/O Map while issuing commands. We need to see whether the appropriate value changes on the drive immediately when commands are given. 

On the drive's keypad, from the Main Menu:

1. Select Drive Menu (push in on the wheel with Drive Menu highlighted)
2. Scroll down (turn the wheel clockwise) to and select menu 1.2 Monitoring
3. Select I/O Map
4. Scroll down and select Analog Inputs Image. AI1 and AI2 will be listed on the left of the screen with their respective values on the right
5. While staying on this screen, monitor the voltage or current value (whichever is being used) while you change the speed reference from your control circuit

If the voltage or current reading changes immediately when the reference signal changes, then the Accel and Decel times in the drive's programming might need to be adjusted down to accomplish a faster speed change. And if the readings change after some lag, then the issue is with the speed reference signal coming in.

For additional reference please see the ATV61 Programming Manual:
-How to get to the Analog Inputs Map- pages 39-40 
-Modifying the Accel and Decel times- page 38
 
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