Siemens Sentron PAC3200 Power Meter Energy Readings


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?

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
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?

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.

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