Powerflex70 speed does not follow 4-20ma signal

We are using powerflex70. But when analog current input is 4mA, drive para 16 is 6.8mA. When current is 12mA, it is 20mA. I checked all the config, it seems nothing is wrong. Analog input hi is set at 20mA and analog input lo is 4mA. Can anyone tell me why?

I am fairly new at this but it looks like you have your analog scaling off. Make sure it is set to the default of Configuration 1. Looks like you may be closer to Config 3.

Look under Analog Inputs 2-12 to 2-14 in the manual I have.

xinjiang said:

We are using powerflex70. But when analog current input is 4mA, drive para 16 is 6.8mA. When current is 12mA, it is 20mA. I checked all the config, it seems nothing is wrong. Analog input hi is set at 20mA and analog input lo is 4mA. Can anyone tell me why?

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I infer from your reference to Parameter 16 that you are using Analog Input 1 on Terminals 16 & 17. Try using Analog Input 2 on Terminals 20 & 21. Make sure you change your Speed Command Source in Parameter 90, and the Scaling in Parameters 91, 92, 325, and 326 for your application. You can monitor the Input Current with Parameter 17.

Stu.....

The results you are getting are linear which has me thinking you may be introducing an error into your readings.

So are you able to measure the voltage across the drive input terminals, and read the current reading at para 16 at the same time, then apply ohms law to find the resistor value inside the drive.
Or post your readings

Voltage is measured in parallel with the input terminals.
Current in mA is measured in series with one of the input terminal leads.

I applied 4mA and para.16 is reading 5.554mA. I measured voltage across terminal 16 and 17, it is 0.557V. Still have no idea why.