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How to get 64-Bit modbus register data to work with my software

Issue
Modbus devices such as power meters require the monitoring of values that are held in a 64-bit unsigned integer data format. Some Third Party Software Modbus proxy points cannot be configured to directly support the 64 bit register format.

Product Line
PM800 series
PM5100 series
PM5300 series
PM5500 series
PM8000 series

Environment
Modbus communication

Cause 
Modbus devices such as power meters require the monitoring of values that are held in a 64-bit unsigned integer data format. Some third party software modbus proxy points cannot be configured to directly support the 64 bit register format.

Resolution
As a workaround, the modbus proxy points can be configured to poll the four registers (R1 through R4) as four integers and convert or combine the four integers to a single unsigned 64-bit value using multiplier values (M1 through M4). The formula for combining the individual 16-bit registers to construct a 64-bit register is M1*R1+M2*R2+M3*R3+M4*R4
NOTE: that all four registers will need to be polled in a single message.  

For integer values:
Use the multipliers as follows for the four seperate registers
M1 = 20 = 1
M2 = 216 = 65536
M3 = 232 = 4294967296
M4 = 248 = 281474976710656​


For mod10k values:
M1 = 100 = 1
M2 = 104 = 10000
M3 = 108 = 100000000
M4 = 1012 = 1000000000000

 
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