Function mbcu_read

Function for reading COILS on a modbus server by specifying the unit ID.

Syntax

i32 mbcu_read_coils (i32 mbc, i32 unitID, i32 offsCoilsStart, i32 nCoil, dest)

mbc

Handle value returned by mbc_init()

unitID

Value of the unit ID to be used

offsCoilsStart

Initial index of the COIL

nCoil

Number of COILS to be read from offsCoilsStart.

NOTE: The maximum number of COILS that can be read is 2000.

dest

Area where to put the read data.

Can be i16/u16/i32 or array of i16/u16/i32

Result

Returns:

Value	Meaning
0 [MBC_OK]	Command executed
-1 [MBC_INVAL]	Invalid arguments
-2 [MBC_BUSY]	Resource occupied
-3 [MBC_PERM]	Permission denied
-4 [MBC_CONN]	Connection failed
-5 [MBC_NOBUFS]	Buffer exhausted
-6 [MBC_NOMEM]	Insufficient memory
-7 [MBC_TX_ERR]	Transmission error
-8 [MBC_RX_ERR]	Receive error
-9 [MBC_TIMEOUT]	Blocking command timeout
-10 [MBC_EXC_CODE_1]	Response with exception 1 (function code not supported by server)
-11 [MBC_EXC_CODE_2]	Response with exception 2 (invalid address)
-12 [MBC_EXC_CODE_3]	Response with exception 3 (invalid quantity or value)
-13 [MBC_EXC_CODE_4]	Response with exception 4 (operation failed)
-14 [MBC_WRONG_ANSWER]	Invalid response
-15 [MBC_INVAL_MBC]	Invalid mbc id

Validity

Task

Note

The function is blocking. Exits only when the task is completed

Please enable JavaScript to view this site.