Datakom DPR-350 Series, Руководство пользователя

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DPR-350 User Manual Ver_01 Firmware V-1.0
K91D01-EN - 62 -
The unit offers MODBUS in the following modes:
-RS485 serial port, adjustable baud rate from 2400 to 115200
MODBUS features of the device:
-Data transfer mode: RTU
-Serial data: adjustable baud rate, 8 bit data, no parity, 1 bit stop
-Supported functions:
-Function 3 (read multiple registers)
-Function 6 (write single register)
-Function 16 (write multiple registers)
Each register consists of 2bytes (16 bits). Larger data structures are provided using multiple registers.
Each device in the Modbus communication network must have a distinct address. The unit supports
addresses in the range 1-247.
Modbus Address:
May be set as a value between 1 and 240.
RS-485 Enabled: Must be set as 1 (or the parameter box must be checked).
RS-485 Baud Rate: Adjustable between 2400 and 115200 bauds. Every device in the communication
group must have the same baud rate.
Increasing the baud rate provides faster communication at a shorter communication distance. Decreasing
the baud rate allows communication at longer distances with a slower rate of data transmission.
9600 bauds communication speed can be reached with a 120ohm balanced cable at 1200m distance.
16-bit variables: These variables are stored in a single register. Bit_0 is the least significant bit (LSB)
and Bit_15 is the most significant bit (MSB).
32-bit variables: These variables are stored in 2 consecutive registers. The 16 least significant bits are
located in the first register and the 16 most significant bits are located in the second register.
Bit arrays: Arrays larger than 16 bits are stored in multiple registers. The LSB of the first register is bit_0.
The MSB of the first register is bit_15. The LSB of the second register is bit_16. The MSB of the second
register is bit_31, and so on.
22. MODBUS COMMUNICATIONS
Each device in the RS-485 serial network must have a distinct
address. Otherwise, Modbus communication will not function.
22.1. PARAMETERS FOR RS-485 MODBUS COMMUNICATION
22.2. DATA FORMATS