Explanation of function codes, B–10, Appendix b – Hitachi L2002 User Manual
Page 246
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 [5] 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]
Coil Status
ON
ON
ON
OFF
ON
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