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I have an energy meter (OHIO A2000) which has been now discontinued by the manufacturer. Anyway, I'm following the manual for extracting energy parameters through Modbus RS485 communication. I'm getting most of the parameters accurately (i.e, A, VLL, KW, PF..) but I'm having trouble getting the total kWh value from the attached picture. How can I get the total kWh value 819371.8 from the Modbus registers?


A2000 display


2018-12-21 13:45:52.367 <02048> 34 32645 49 1399 41 -18381 125 15663 25 -19692 31 20483 39 19877 96 20668


This is the data log from register 0800h-080fh. These are represented as EnergyMeters in the manual. These should be multiplied with 10^2 to get the actual values.(Dim.P = 2). But I'm having trouble in interpreting these values, which entry belongs to what value? Also, I don't see any entry from these values would result in the total kWh (819371.8).

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  • \$\begingroup\$ That number 819371.8 seems to be labelled k Wh, is that what you are looking for? \$\endgroup\$ – Solar Mike Dec 21 '18 at 7:10
  • \$\begingroup\$ 2018-12-21 13:45:52.367 <02048> 34 32645 49 1399 41 -18381 125 15663 25 -19692 31 20483 39 19877 96 20668 \$\endgroup\$ – imvinaypatil Dec 21 '18 at 8:18
  • \$\begingroup\$ This is the data log from register 0800h-080fh. These are represented as EnergyMeters in the manual. These should be multiplied with 10^2 to get the actual values.(Dim.P = 2). But I'm having trouble in interpreting these values, which entry belongs to what value? Also, I don't see any entry from these values would result in the total kWh (819371.8) @SolarMike \$\endgroup\$ – imvinaypatil Dec 21 '18 at 8:32
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    \$\begingroup\$ (125 * 2^16 + 15663) * 100 = 820766300, which is close to the value in that picture. \$\endgroup\$ – BeB00 Dec 21 '18 at 8:56
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    \$\begingroup\$ @imvinaypatil the reading itself is a 32 bit value, but the modbus is sending it as two 16 bit values, MSB first. In order to get the correct result, you left shift the first value by 16 (which is the same as multiplying by 2^16) and add it to the second value \$\endgroup\$ – BeB00 Dec 21 '18 at 9:19

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