PowerLogic PM5563 Data Log Loss of Precision after 1B Wh

[NortheastSolar]

We have come across an unfortunate behavior in the Ion Setup Data Log retrieval for PM5563 meters

Up until one shy of a billion on the meter, retrieving the Wh Data Log would produce a listing of 15-minute intervals precise to 1 watt-hours

As soon as the meter went over 1B, the log retrieval started using scientific notation precise only to the one-million-th watt hours. If I log into the meter's web interface directly, the wh counter is correct.

So for example on the meter web interface:

1006467208 Wh

is only being transmitted to Ion Setup as:

1006000000 Wh

How can Ion Setup be configured to retrieve data accurate to 1 Wh again?

Thanks in advance

[Charles_Murison]

Hello @NortheastSolar ,

There are a number of factors that can come into play here. One of the big ones is what format for the number is being used. 32-bit float (IEEE 754, also know as Single-precision floating-point format) has limitations on resolution depending how big the number is. 1006467208 cannot be represented as a floating point number, the closes number would be 1006467200. The meter's web page might be using internal features such as int32, 64 bit float or some other method that cannot be used external to the meter.

When numbers get large, there is no way to keep resolution down to 1 kwh and still have large numbers when numbers are encoded with 32-bit floating point.

So short answer is no, not possible to for ION Setup. Why the resolution is that much lower in ION Setup I am not sure.

Regards,

Charles 

[NortheastSolar]

Hi Charles, 10 or 100 Wh precision would be workable but as it stands one million Wh precision is essentially unusable for us.

So the question becomes if either of the following options are possible:

- Subtract 1B from the total before transmitting to ION, or

- Transmit 10 or 100 Wh precise numbers to ION

Alternatively is there an alternative to ION to retrieve 15-minute interval data?

[Robert_Lee · Accepted solution]

What version of ION Setup are you using?  I suggest downloading the latest version from the following location: ION Setup Latest Release | Schneider Electric

Depending on how long ago the device has been since the data log has been programmed, you may need to reprogram the data log again with the latest version which should permit the UINT64 version of the energy registers and not the FLOAT32 version (which is what I believe is happening).

Below I've reprogrammed my PM556X device data log with the latest version and preset the energy register to the same number as you posted above and it is showing up fine.