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VACON® 1000 Fieldbus Options
Operating Guide
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Read command: 0x0000–0x00F3
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Write command: 0x4000–0x40F3
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Complete the function of mapping address without conflict by software through "calculate mapping address automatical-
ly".
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When using "auto mapping function", first configure the corresponding Modbus register address and data numbers.
•
Mapping bit
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For the bit operation commands, the position range of start-bit is in byte 0–7.
•
Byte swap
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There are 3 kinds of types: Non-exchange, Double-byte-exchange, and four-byte-exchange.
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In Modbus and PROFIBUS DP byte order, the most significant bit (MSB) takes precedence.
-
In DeviceNet
byte order, the least significant bit (LSB) takes precedence.
™
-
If necessary, exchange the byte order to get the correct value.
•
Type of scan
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There are 2 kinds of scanning mode: Quick-scan and slow-scan.
-
Slow-scan is equal to quick-scan being multiplied by scan rate. Set the scan rate in Subnet configuration.
4.6 Working Principle of the Modbus Master Station
A mapping relation establishes the data conversion between Modbus and the PROFIBUS DP module. The PROFIBUS DP module has
2 data buffers:
•
PROFIBUS network input buffer with address of 0x00-0xF3
•
PROFIBUS network output buffer with address of 0x4000-0x40F3
Commands 1, 2, 3, and 4 of Modbus write the data read from the Modbus slave station into the network input buffer. Then the
PROFIBUS network reads the data. Commands 5, 6, 15, and 16 of the Modbus write the data from the network output buffer into the
Modbus slave station. The data saved in the network output buffer is the data that the PROFIBUS master station writes to the PROFI-
BUS DP module.
48 commands can be configured. Every command can read a set of continuous Modbus registers.
4.7 Universal Mode
4.7.1 Data Conversion
The PROFIBUS DP module implements data conversion between PROFIBUS DP fieldbus protocol and serial port devices with RS232/
RS485/RS422 serial interface. The conversion and transmission between PPROFIBUS DP data and serial port data is bidirectional.
PROFIBUS output data
Eo i D1 D2 ...
Di 0
...
Serial port output data
D1 D2 ... Di
Illustration 14: Data Conversion Block Diagram
Danfoss A/S © 2023.09
PROFIBUS DP Bus
Eo j D1 D2 ...
PROFIBUS DP module
User serial device
PROFIBUS input data
Dj 0
...
Serial port input data
D1 D2 ... Dj
PROFIBUS DP
AQ454734633756en-000101 / 172K1112 | 45
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