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Chapter 4 Explanation of Functions
(4) Explanation of function codes
(i) Reading the coil status [01h]
This function reads the coil status (on or off).
(Example)
When reading the status of the intelligent input terminals [1] to [6] of the inverter at slave address "8":
Assume that the intelligent input terminals are in the status as shown below.
Intelligent input terminal 1 2 3 4 5 6
Coil number 7 8 9 10 11 12
Terminal status ON ON ON OFF ON OFF
Coils 13 and 14 are off.
Query
Field name Sample setting
(hexadecimal)
1 Slave address (*1) 08
2 Function code 01
3 Starting coil number
(upper digit) (*2)
00
4 Starting coil number
(lower digit) (*2)
06
5 Number of coils (upper digit)
(*3)
00
6
Number of coils (lower digit)
(*3)
06
7 CRC-16 code (upper digit) 5C
8 CRC-16 code (lower digit) 90
*1 This query cannot be broadcasted.
*2 Note that the starting coil number is 1 less than the
actual coil number of the coil to be read first.
*3 If 0 or a value more than 32 is specified as the number
of coils to be read, the inverter will respond with error
code "03h".
Response
Field name Sample setting
(hexadecimal)
1 Slave address 08
2 Function code 01
3 Number of data bytes 01
4 Coil data (*4) 17
5 CRC-16 code (upper digit) 12
6 CRC-16 code (lower digit) 1A
*4 The data as many as the specified number of data
bytes is transferred.
The data received in the response indicates the status of coils 7 to 14. Read the received data (17h =
00010111b) as shown below. The least-significant bit indicates the status of coil 7.
Coil number 14 13 12 11 10 9 8 7
Coil status OFF OFF OFF ON OFF ON ON ON
If the query has specified the reading of an undefined coil, the data on the said coil is represented by "0"
in the response.
If the function to read the coil status cannot be executed normally, the inverter will return an exception
response. For details, see Item (viii), "Exception response."
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