Emerson Unidrive M701 - Number of 16-Bit Registers (LSB); Number of 16-Bit Registers (MSB)

SI-Ethernet User Guide 125
Issue: 1
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7.2.9 FC16 – Write multiple registers
This function code allows a contiguous series of registers to be written. The maximum
number of registers that can be written is 120, this allows up to 120 16-bit parameters
or 60 32-bit parameters to be read in a single transaction. If this is exceeded the server
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.
If 32-bit parameter addressing is used, then for each parameter written:
• Two 16-bit registers must be used in the request
• Four bytes must be specified in the request
• The number of registers written in the response will be twice the number of
parameters written
Master request data Slave response data
Byte Description Byte Description
7 Function code 0x10 7 Function code 0x10
8
Start register address
(MSB)
8
Start register address
(MSB)
9
Start register address
(LSB)
9
Start register address
(LSB)
10
Number of 16-bit registers
(MSB)
10
Number of 16-bit registers written
(MSB)
11
Number of 16-bit registers
(LSB)
11
Number of 16-bit registers written
(LSB)
12
Length of register data to write
(Bytes)
13
Register data
(MSB)
14
Register data
(LSB)