New Cosmos Electric PS-7-M, Communication Specifications Manual

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6.4.3 Function Code 16 (Write Multiple Holding Registers)
Function code 16 (0x10) is used to write a block of contiguous data to the specified multiple
registers.
Example of request message
The master sends function code = 16 (0x10) to the slave (unit ID = 03). “Test mode ON command”
and “test gas concentration” will be written to register addresses 40048 (relative address = 47
(0x002F)) and 40049 (relative address = 48 (0x0030)) respectively.
Test mode ON command = ON (0x0001)
Test gas concentration = 25%F.S. (0x0019)
Message frame Modbus TCP Modbus RTU Remarks
Data item Data
size
(byte) No. Byte
data Hex No. Byte
data Hex
TRXN ID Hi 2 (1) 0 0x00 – – – Modbus TCP
only
Lo (2) 0 0x00 – – –
Protocol
ID Hi 2 (3) 0 0x00 – – – Modbus TCP
only
Fixed at “00”.
Lo (4) 0 0x00 – – –
Quantity
of comm.
data Hi 2 (5) 11 0x00 – – – Modbus TCP
only
Number of data
which follows
unit ID
Lo (6) 0x0B – – –
Unit ID 1 (7) 3 0x03 (1) 3 0x03
Function code 1 (8) 16 0x10 (2) 16 0x10
Starting
address
Hi 2 (9) 47 0x00 (3) 47 0x00 Write starting
register address
Lo (10) 0x2F (4) 0x2F
Quantity
of
registers Hi
２
(11) 2 0x00 (5) 2 0x00 Quantity of
registers to be
written
Range: 1–123
Lo (12) 0x02 (6) 0x02
Quantity of
data 1 (13) 4 0x04 (7) 4 0x04 Quantity of data
= N x 2 bytes
N: Quantity of
registers
Data1 Hi 2 (14) 1 0x00 (8) 1 0x00 Write data by
the word
Lo (15) 0x01 (9) 0x01
Data2 Hi 2
(16) 25 0x00 (10) 25 0x00
Lo (17) 0x19 (11) 0x19
Error
check
data Lo 2 – – – (12) 0x2A Modbus RTU
only
Hi – – – (13) 0x45
Common to both Modbus TCP and Modbus RTU.