Hitachi X200-002SFE/NFU Instruction Manuals page 237

B−10
Explanation of function codes
Read Coil Status [01h]:
This function reads the status (ON/OFF) of selected coils. An example follows below.
• Read intelligent input terminals [1] to [5] of an inverter having a slave address "8."
• This example assumes the intelligent input terminals have terminal states listed
Query:
Note 1:
Note 2:
Note 3:
Note 4:
• The data set in the response shows terminal state of coils 7 to 14.
• Data "05h = 00000101b" indicates the following assuming coil 7 is the LSB.
• When a read coil is outside the defined coils, the final coil data to be transmitted
• When the Read Coil Status command cannot be executed normally, see the exception
More user manuals on
below.
Item
Intelligent input
[1]
terminal
Coil number 7
Coil Status ON
No. Field Name
1 Slave address *1
2 Function code
3 Coil start address *4
(high order)
4 Coil start address *4
(low order)
5 Number of coils
(high order *2)
6 Number of coils
(low order *2)
7 CRC-16 (high order)
8 CRC-16 (low order)
Broadcasting is disabled.
When 0 or more than 31 is specified as a number of coils, error code "03h" is
returned.
Data is transferred by the specified number of data bytes (data size).
The PDU Coils are addressed starting at zero. Therefore coils numbered 1-31
are addressed as 0-30. Coil address value (transmitted on Modbus line) is 1
less than the Coil Number.
Item
Coil Number 14
Coil Status OFF
contains "0"as the status of the coil outside the range.
response.
ManualsBase.com
Data
[2] [3] [4] [5]
8 9 10 11
OFF ON OFF OFF
Response:
Example
No. Field Name
(Hex)
08 1 Slave address
01 2 Function code
00 3 Data size (in bytes)
06 4 Coil data *3
00 5 CRC-16 (high order)
05 6 CRC-16 (low order)
1C
91
Data
13 12 11
OFF OFF OFF
Example
(Hex)
08
01
01
05
92
17
10 9 8
OFF ON OFF
7
ON