The energy rollover value for a 3710 is 999 999 999 kWh. Why are the modbus energy readings rolling over at 65535 KWh?



The 3710 Modbus protocol supports both 16-bit and extended 32-bit registers (the register size is selectable from the front panel). 32-bit registers are used for large value such as energy values while 16-bit registers are used for other parameters, such as current or voltage.
The kWh is rolling over at 65535 since it is being read as a 16-bit register, but it should be a 32-bit value; only the low byte of the 32-bit register is being read. Changing the modbus read mode to 32-bit will provide the correct kWh reading.



Original article#16757

Last Revised: 4 July 2007


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Legacy KB System (APS) Data: RESL186856 V1.0, Originally authored by KBAdPM on 07/11/2007, Last Edited by KBAdPM on 07/11/2007
Related ranges: 3710 ACM