Emerson E300 Series - Page 481

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CT MODBUS RTU Technical Data
E300 Design Guide 481
Issue Number: 1
Master request
Slave response
Example
Read Pr 00.011 to Pr 00.014 with 32 bit data access
Master request
Slave response
FC06 Write single register
Writes a single 16 bit value to a register. The normal response is an echo
of the request (unless an exception occurs) returned after the parameter
has been written.
The register address can correspond to a 32 bit parameter, but only the
lower 16 bits of the value will be written.
Master request
Slave response
Example
Write the value 0x0000 to Pr 00.020 (Pr 18.012)
Master request
Slave response
FC16 - Write multiple registers
This function code allows a contiguous series of registers to be written.
The drive imposes an upper limit on the number of registers to be written
(16 in the case of CSD100), and if this is exceeded the drive will issue an
exception response code 2.
The normal response includes the function code, start register address
and number of 16 bit registers written (unless an exception occurs),
returned after the parameters have been written.
Byte Description
0 Slave destination node address (1 – 247, 0 is global)
1 Function code 0x03
2 Start register address MSB
3 Start register address LSB
4 Number of 16 bit registers to read MSB
5 Number of 16 bit registers to read LSB
6 CRC LSB
7 CRC MSB
Byte Description
0 Slave destination node address
1 Function code 0x03
2 Length of data in read block (bytes)
3 Register data 0 MSB
4 Register data 0 LSB
3+byte count CRC LSB
4+byte count CRC MSB
Byte Value Description
0 0x01 Slave destination node address
1 0x03 Function code 0x03
20x40
Start register Pr 00.011
(16384 + (100 x 0) + 11 – 1) = 16394 = 0x400A
30x0A
40x00
Number of 16 bit registers to read
4 x 32 bit register = 8 x 16 bit registers
50x08
60x71CRC LSB
70xCECRC MSB
Byte Value Description
0 0x01 Slave destination node address
1 0x03 Function code 0x03
20x10
Length of data (bytes) = 4 x 32 bit registers = 16
bytes
3-6 Pr 00.011 data
7-10 Pr 00.012 data
11-14 Pr 00.013 data
15-18 Pr 00.014 data
19 CRC LSB
20 CRC MSB
Byte Description
0 Slave destination node address (1 – 247, 0 is global)
1 Function code 0x06
2 Start register address MSB
3 Start register address LSB
4 Register data MSB
5 Register data LSB
6 CRC LSB
7 CRC MSB
Byte Description
0 Slave destination node address
1 Function code 0x06
2 Start register address MSB
3 Start register address LSB
4 Register data MSB
5 Register data LSB
6 CRC LSB
7 CRC MSB
Byte Value Description
0 0x01 Slave destination node address
1 0x06 Function code 0x06
20x00
Start register Pr 00.020
(100 x 0) + 20 – 1) = 19 = 0x0013
30x13
4 0x00 Register data MSB
5 0x00 Register data LSB
6 0x78 CRC LSB
7 0x0F CRC MSB
Byte Value Description
0 0x01 Slave destination node address
1 0x06 Function code 0x06
2 0x00 Start register MSB
3 0x13 Start register LSB
4 0x00 Register data MSB
5 0x00 Register data LSB
60x78CRC LSB
70x0FCRC MSB