2 02 (0x02) read discrete inputs, 3 03 (0x03) read holding registers, 4 04 (0x04) read input registers – Yokogawa EJX930A User Manual
Page 33: 5 05 (0x05) write single coil, 02 (0x02) read discrete inputs -2, 03 (0x03) read holding registers -2, 04 (0x04) read input registers -2, 05 (0x05) write single coil -2
<5. Modbus Communication>
5-2
IM 01C25R05-01EN
5.4.2 02 (0x02) Read Discrete Inputs
Specified quantity of Discrete Inputs contents is
read from Specified Starting Address.
Not corresponding to Broadcast.
Request
Items
Size [byte]
Data
Address
1
1 to 247
Function code
1
0x02
Starting Address
2
0x0000 to 0xFFFF
Quantity of Inputs 2
-
CRC
2
-
Response
Items
Size [byte]
Data
Address
1
1 to 247
Function code
1
0x02
Byte count
1
N
*1
Input Status
*2
N
*1
CRC
2
-
*1:
N is 1 when quantity of Discrete Inputs is less than or
equal to 8.
*2:
e.g. When reading address is 1000 – 1007, MSB is 1007
and LSB is1000.
5.4.3 03 (0x03) Read Holding Registers
Specified quantity of Holding Registers contents is
read from Specified Starting Address.
Not corresponding to Broadcast.
Request
Items
Size [byte]
Data
Address
1
1 to 247
Function code
1
0x03
Starting Address
2
0x0000 to 0xFFFF
Quantity of
Registers
2
-
CRC
2
-
Response
Items
Size [byte]
Data
Address
1
1 to 247
Function code
1
0x03
Byte count
1
N
*1
×2
Register value
*2
N
*1
×2
CRC
2
-
*1:
N: The quantity specified by the Quantity of Registers.
*2:
Transmitted by the order: Upper- Lower from the specified
Starting Address.
E.g. 10 in FLOAT format, Transmit order is as
0x41200000.
5.4.4 04 (0x04) Read Input Registers
Specified quantity of Input Registers contents is
read from Specified Starting Address.
Not corresponding to Broadcast.
Request
Items
Size [byte]
Data
Address
1
1 to 247
Function code
1
0x04
Starting Address
2
0x0000 to 0xFFFF
Quantity of
Registers
2
-
CRC
2
-
Response
Items
Size [byte]
Data
Address
1
1 to 247
Function code
1
0x04
Byte count
1
N
*1
×2
Register value
*2
N
*1
×2
CRC
2
-
*1:
N: The quantity specified by the Quantity of Registers.
*2:
Transmitted by the order: Upper- Lower from the specified
Starting Address.
E.g. 10 in FLOAT format, Transmit order is as
0x41200000.
5.4.5 05 (0x05) Write Single Coil
Write data to Coil of Specified Output Address.
Corresponding to Broadcast.
Request
Items
Size [byte]
Data
Address
1
1 to 247
Function code
1
0x05
Output Address
2
0x0000 to 0xFFFF
Output Value
2
0x0000 or 0xFF00
*1
CRC
2
-
*1:
OFF; 0x0000, ON; 0xFF00
Response
Items
Size [byte]
Data
Address
1
1 to 247
Function code
1
0x05
Output Address
2
0x0000 to 0xFFFF
Output Value
2
0x0000 or 0xFF00
CRC
2
-