i have two cases AC drive controlling a motor
in open loop and in closed loop.. i want to know whether the output frequency AO1(4-20ma) is the actual motor frequency is it is just an estimation in both cases.. thanks for your time

 

The output frequency is not actually the motor speed, it is the summation of actual motor speed (in terms of frequency) and slip frequency. if slip compensation is present in the drive or slip compensation option is activated, the output frequency will be almost equal to the actual frequency or it is more appropriate that actual speed will always try to achieve the output frequency but always there will be little bit less than it.

 

It's probably a very close approximation of the output frequency. These things are all digital these days so you get very good output signals.

OTOH, most are also configurable and sometimes the default output signal range is not especially obvious. I have seen the default be things like 4-20ma = 0-132 Hz. I have also seen some where they use 0-20 mA as an output.