Vega VEGAPULS 63 - 11 Supplement: Modbus Protocols and Parameters; Protocol Description & Bus Parameters

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11 Supplement
VEGAPULS 63 • Modbus and Levelmaster protocol
41364-EN-170711
Protocol description
The VEGAPULS 63 is suitable for connection to the following RTUs with Modbus RTU or ASCII
protocol.
RTU Protocol
ABBTotalow Modbus RTU, ASCII
Bristol ControlWaveMicro Modbus RTU, ASCII
Fisher ROC Modbus RTU, ASCII
ScadaPack Modbus RTU, ASCII
Thermo Electron Autopilot Modbus RTU, ASCII
Parameters for the bus communication
The VEGAPULS 63 is preset with the default values:
Parameter CongurableValues Default Value
Baud Rate 1200, 2400, 4800, 9600, 19200 9600
Start Bits 1 1
Data Bits 7, 8 8
Parity None, Odd, Even None
Stop Bits 1, 2 1
Address range Modbus
1 … 255 246
Startbitsanddatabitscannotbemodied.
Generalcongurationofthehost
Thedataexchangewithstatusandvariablesbetweenelddeviceandhostiscarriedoutvia
register.Forthis,acongurationinthehostisrequired.Floatingpointnumberswithshortprevision
(4 bytes) according to IEEE 754 are transmitted with individually selectable order of the data bytes
(byte transmission order). This "Byte transmission order" is determined in the parameter "Format
Code". Hence the RTU knows the registers of the VEGAPULS 63 which must be contacted for the
variables and status information.
Format Code Byte transmission order
0 ABCD
1 CDAB
2 DCBA
3 BADC
11.3 Modbus register
Holding Register
The Holding registers consist of 16 bit. They can be read and written. Before each command, the
address (1 byte), after each command, a CRC (2 byte) is sent.