PWS and Measured Output for Current Measurement

[ENI_78]

Hello,

I need information regarding the accuracy of the current measurement for the VI Measured Output (PWS) or how to calculate it.

Is the measured value equal to the DMM-measurement?

Regards

[Russ_B.]

Hello,

I assume you're talking about the "Readback Accuracy" spec of the DC Power Supply.

It's specs are "±(% of Reading + Offset)".  

The "% of Reading" value is the reading returned by the power supply.  It is multiplied by the gain error.  Then the offset is added to it to get the totall ± error. 

Hope that helps.

Thanks

Russell

[ENI_78]

Hello,

Thanks for the answer.
Can you give me an example of how the offset is calculated?

For example, I measure 16mA at 5V voltage output.

What is the current tolerance + -? mA

Thanks

E. I.

[Russ_B.]

Hello,

I'm going to have to make some assumptions about your setup.  I'm assuming you're using a VB-8012 and that you are using the 0-6V power supply.

The read-back accuracy is listed as ±(0.2% + 10mA).  

The 10mA is the offset error.  That error is there regardless of the output, even if it's 0mA.  0.2% is the gain error.  You'll notice that offset error dominates the total accuracy since even at the max current (1A) there is only 2mA of gain error. 

So, for your application the total error = ±(0.2% * 16mA + 10mA) = ±10.032 mA

Notice that if you use the 0 to +25V power supply you actually get better read-back accuracy.  Of course the trade-off is that you get a lower max current (500mA compared to 1A).

Hope that helps!

Russell

[ENI_78]

Hello Russell,
many thanks for your response.
Greeting

E.I.