Accuracy of AP7152 / AP7155 / AP7175 power meters

[DCIM_Support]

Hello,

I have a question about the accuracy of AP7152(B) / AP7155(B) / AP7175(B) power meters. We would like to measure our colocated costumer power consumption and allow them access to these power meters. My question is how sensitive or accurate are they ? Are we able to use them for this purpose or do we have to buy something else from Schneider / APC ? 

PS: We want to measure instant power and energy used over a period of time.

Thanks a lot,

Peter

(CID:126159838)

[DCIM_Support]

Hi petru bunea,

In continuation of your old theme , I can answer: I was also interested in this issue recently, i.e. accuracy of measurements, and could not find any official documentation. Therefore, I made practical measurements and now I get such interesting information.

Regarding old power meters AP7152, AP7155 and AP7175: I repeat, this power meters is already discontinued. This discontinued power meters has the latest firmware is rpdu v3.9.2, therefore, we have the following measurement characteristics:

• current consumption measurement: YES
• minimum measured current consumption: 1A
• accuracy of measuring the current consumption (in the range >1A): 0.1A
• measuring the input voltage: NO (the nominal voltage constant is stored in the ROM of the power meter, for example, 231V)
• power consumption measurement: software (by multiplying the measured current consumption by the constant of the nominal voltage)
• measurement of consumed electrical energy: NO

Therefore, these old power meters can not be used if:

• the power of the customer equipment is less than 231V * 1A = 231W (for powerlines with a nominal voltage of 231V);

• the input voltage is not exactly the nominal voltage of the power meter, for example, instead of 231V (for powerlines with a nominal voltage of 231V) is supplied 220V. Then the calculated power will be absolutely wrong.

Therefore, if the power of the customer equipment exceeds 231W (for powerlines with a nominal voltage of 231V), then the accuracy of power calculation will be 231V * 0.1A = 23W.

And at last, it will be necessary to calculate the consumed electrical energy by third-party software. Moreover, the accuracy of the calculation will be higher the more often the measurements are performed (for example, for a DCE-server - this is not more often than once per minute).

Regarding new power meters AP7152B, AP7155B and AP7175B: this power meters has the latest firmware is rpdu2g v6.4.4, therefore, we have the following measurement characteristics:

• current consumption measurement: YES
• minimum measured current consumption: 0.5A
• accuracy of measuring the current consumption (in the range >0.5A): 0.1A
• measuring the input voltage: YES
• accuracy of measuring the input voltage (in the range of nominal voltage): 1V
• power consumption measurement: YES
• accuracy of measuring the power consumption (in the range >100W): 10W
• measurement of consumed electrical energy: YES
• accuracy of measuring the electrical energy (in the range >100W): 0.1kW*h

Therefore, these new power meters can not be used only if:

• the power of the customer equipment is less than 100W (for powerlines with a nominal voltage of 231V).

Therefore, if the power of the customer equipment exceeds 100W (for powerlines with a nominal voltage of 231V), then the accuracy of power measurement will be 10W and the accuracy of electrical energy will be 0.1kW*h.

I hope I answered your question and it will help you.

P.S.: also I hope that I fully answered your previous question  😀.

(CID:126160061)

[DCIM_Support]

Hi petru bunea,

Have you been able to solve this issue or not?

With respect.

(CID:126163999)

[DCIM_Support]

This question is closed for comments. You're welcome to start a new topic if you have further comments on this issue.