PowerFlex 40 using 4-20mA trim

I have a PowerFlex 40 with a 0-10VDC analog in for the main speed reference. I also have a 4-20 mA signal set up for
Setpnt Trm (A312=5)and parameters A112 and A113 (100 and 0% resp.) reversed so that an increasing signal will increase the trim.
Everything works except for when the 4-20Ma signal gets above
19.97 mA at which monitor variable for the 4-20mA (D021) equals or exceeds 100% signal, the drive will drop to a speed less than the main speed reference. This is not working too well since the control has to run full speed in this condition. There are not too many loop signals that do not exceed 20mA to some degree. Is there a parameter I'm missing to have the drive continue at full speed at mA >= 100%?

I have the PID basically turned off. A134 = .3, A135 = 0 and A136 = 0. PID Setpoint around 53% and trim at +- 5HZ.

Thanks

I believe that on the Powerflex, you can set the range for the signal. Change the 4-20 mA signal range to 4-21 mA or something similar.

Alternate: On the device that produces the 4-20 mA signal, change it to produce slightly less than 20 mA, say 19.75 mA.

You may be running into current limiting at full speed. The VFD can be configured to clamp the motor speed when the motor current reaches the max value. Check the amperage of the motor at the drive display, and make sure you are not approaching overload.

Thanks for the response(s). You can set the 4-20 mA range in percent but it will only go up to 100%. I have since talked with Allen & Bradley, they were able to duplicate the problem as a confirmed bug. So I will getting a flash update and I supposed the drive will soon be getting a new version of firmware.