Network Protocol Reference
Appendix B
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 [6] of an inverter having a slave address “8.”
• This example assumes the intelligent input terminals have terminal states listed below.
• The data set in the response shows terminal states of coils 7 to 14.
• Data “17h = 00010111b” indicates the following assuming coil 7 is the LSB.
Item Data
Intelligent input
terminal
[1] [2] [3] [4] [5] [6]
Coil Status ON ON ON OFF ON OFF
Item Data
Coil Number 14 13 12 11 10 9 8 7
Coil Status OFF OFF OFF ON OFF ON ON ON
Query:
Note 1: Broadcasting is disabled.
Note 2: When 0 or more than 32 is
specified as a number of coils,
error code “03h” is returned.
Response:
Note 3: Data is transferred by the
specified number of data bytes
(data size).
No. Field Name
Example
(Hex)
1 Slave address *1 08
2 Function code 01
3 Coil start number
(high order)
00
4 Coil start number
(low order)
07
5 Number of coils
(high order) *2
00
6 Number of coils (low
order) *2
06
7 CRC-16 (high order) 0D
8 CRC-16 (low order) 50
No. Field Name
Example
(Hex)
1 Slave address 08
2 Function code 01
3 Data size (in bytes) 01
4 Coil data *3 17
5 CRC-16 (high order) 12
6 CRC-16 (low order) 1A
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