# Siemens Sentron PAC3200 Power Meter Energy Readings

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Thread Starter

#### Terence Ng

How can I retrieve the energy reading from Siemens Sentron PAC3200 power meter which is Double Register format? I'm using WINPM.Net Software equipvalent to IOn Enterprise from Power Measurement Schneider. How can I break the double register to smaller register such as 16 or 32 bits in order to get the right result?

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#### Elmer Bulman

These double registers are most likely IEEE Single Precision numbers. As such, they will be sent in one of 4 possible byte orders.
1) B0 B1 B2 B3
2) B1 B0 B3 B2
3) B2 B3 B0 B1
4) B3 B2 B1 B0

Your equipment should have a selection of options to decode the proper numbers. Google IEEE Single Precision for bit assignments of float point numbers.
Here are some IEEE Single Precision examples:
B0 B1 B2 B3
1.000 = 0x3f 80 00 00
1.100 = 0x3f 8c cc cd
10.00 = 0x41 20 00 00
10.10 = 0x41 21 99 9a

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#### Terence Ng

If my master does not support 64 bits register, how can I break 64 bits into either 16 bits or 32 bits in order to get the readings? HOw to define the Bits on easy way?

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#### Dan Musiska

Hi,

May I know the difference between the KVAh app. Energy and Kwh readings on the Siemens Sentron PAC3200 Power meter, as I am interested in knowing my daily plant energy consumption.

regards,
Dan

#### imran0413

I have the same problem. In PAC3200 Power meter the energy data (KWH or MWH) is stored in double Float (4 words) registers. I can read these registers but my HMI only supports Single precision Float or real values that contain 2 words (32 bits).
The difference is single precision float has one bit for sign, 7 bits for exponent and 24 bits for mantissa. A double precision float has one sign bit, 10 bits exponent and 53 bits for mantissa.
Honestly there is no simple way to convert a double float to single float except to calculate double float value to numeric value using mathematical formulae and storing result in a single float variable.

Details are here
https://en.wikipedia.org/wiki/IEEE_754

Regards
Imran

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