Delta DPM-D520I, User Manual

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Chapter 5 Parameters and Functions
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The following is packet format of Response sent by Modbus Slave.
After receiving response from the power meter, Modbus Master acquires the value of currents from the
primary-side current transformer (register address 0x000E), which is 1000.
If Modbus Slave (power meter) receives an unusual Request, the packet format for response would be as
follows.
Slave Response
0x01 0x83 0x1
Slave
Address
Function
Code
Exception
Code
CRC
5.2.3 Packet Structure for Funtion Code 0XFE
Function code 0xFE is used to read datas, such as data log, 2~31th harmonics and alarm log, supported only
when using Modbus RTU communication. Similar to Modbus RTU mode, Modbus master sends the Request
message which contains Function code 0xFE- asking the Slave to response with corresponding values in a
Modbus address. Modbus Slave in response sends the requested data.
Eample A (Individual harmonics): If Modbus Master such as PLCs or data collectors reads data log from a
power meter with function code 0xFE in Modbus address 0x0700, the packet format of Request sent by
Modbus Master would be as follows. (Same as Modbus RTU, but Number of Points must be 1)
0x01 0xFE 0x07 0x00 0x00 0x01 CRC
Slave
Address
Function
Code
Start
Address
(Hi)
Start
Address
(Lo)
Number of
Points(Hi)
Number of
Points(Lo)
Master Request