PM5110 Negative Energy Value

[solutions_iems-]

I have a PM5110 power meter that has decided to change an import energy value into an export energy value.

On 12th July at 12:30, the energy reading was 2,147,457.38 kWh

Fifteen minutes later at 12:45, the energy reading became -2,147,483.03 kWh, and has stayed a negative value ever since. All kW values have remained positive.

The meter serial number is 340060199461 and it is connected to an ION 6.0.1 system using the PM5000 LE 6.0.1.11 driver. I know that the driver is not at fault as the other PM5110 power meters connected to the system are still measuring energy as expected.

I have attached a report for this power meter for 12th July 2020.

[Charles_Murison · Accepted solution]

Hello @solutions_iems- ,

‭2147483648‬ is the largest signed integer value for a 32 bit number. If the register is defined as signed, any number larger than this will be considered a negative number in software. Likely there is also scaling involved, possibly 1000. Note that ION Enterprise is very old software and no longer officially supported. You could try looking at the driver to see if possible to change the register to unsigned. 

For your data, you would need to find the 2's complement to the number. It is possible the report is rounding/truncating to 2 decimal places. I would look for the value in the database to be sure. for calculate what the energy should be to manually update. New value = ((2^32)/1000 + logged value)

For example -2147456.15 would be 2147511.146

Regards,

Charles

[solutions_iems-]

Hi Charles

I should have noticed that the value exceeded the limits of a register format!

I have changed the Modbus register for Real Energy into the Load (403204) for the PM5100_LE device driver from S64-87-21 to U64-87-21 format and it has resolved my issue. I will now check the driver types PM5300_LE, PM5350 & PM5500_LE for the same.

Thanks

Iain