AccuEnergy AcuRev 1312, Руководство пользователя

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Chapter 5: Communication
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V: 1.0 Revised: Aug. 2017 V: 1.0 Revised: Aug. 2017
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This chapter introduces users on how to communicate with the AcuRev 1312 through the Mod-
bus communication protocol. A knowledge of the Modbus communication protocol would be
benefi cial for users who will read this chapter.
The chapter’s contents include the Modbus protocol, communication format and application of
the AcuRev 1312 meter.
5.1 Modbus Protocol Introduction
Transmission mode
The mode of transmission defi nes the data structure within a frame and the rules used to trans-
mit the data.
⚫ Coding System 8 bits
⚫ Start bit 1 bit
⚫ Data bits 8 bits
⚫ Parity None/Odd/Even
⚫ Stop bit 1 bit or 2 bits
⚫ Error Checking CRC
Frame:
When the query to the AcuRev 1312 meter (slave device) is received, the meter removes the
frame header and reads the data. If there are no errors, then the meter will implement the data’s
task. Once the task is completed, the meter will put its own data with the acquired header and
send back the frame to the master device that queried the meter. The response data frame con-
tains the address, function, data and CRC check. Any error will cause the response to fail.
Table 5.1 Data frame format
Address Function Data Check
8 bits 8 bits N x 8 bits 16 bits
Address Field: The address fi eld is the data at the start of the frame, It is composed of a 8 bits(1
byte) and corresponds to the device address. It has a decimal value of 1-247.
The master device addresses the slave device by placing the slave device address in the address
fi eld of the message. When the slave sends its response, it places its own address in the address