Yaskawa SMC–4000 - Manual (Page 164)

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SMC–4000 User Manual
MB (Modbus)
[I/O]
DESCRIPTION:
The MB command is used to communicate with I/O devices using the first two levels of the Modbus
protocol.
The format of the command varies depending on each function code. The function code, -1, designates that
the first level of Modbus is used (creates raw packets and receives raw data). The other codes are the 10
major function codes of the second level that the
SMC–4000 supports.
*Note For those command formats that have “addr”, this is the slave address. The slave address
may be designated or defaulted to the device handle number.
*Note All formats contain an h parameter. This designates connection handle number (A thru H).
ARGUMENTS:
Function Meaning Example
-1 Raw Packets MBh = -1, y, array [ ]
1 Read Coil Status MBh = a, 1, t, b, array [ ]
2 Read Input Status MBh = a, 2 , t, b, array [ ]
3 Read Holding Registers MBh = a, 3, e, r, array [ ]
4 Read Input Registers MBh = a, 4, e, r, array [ ]
5 Write Single Coil MBh = a, 5, t, c
6 Write Single Register MBh = a, 6,g, s
7 Read Exception Status MBh = a, 7, array [ ]
15 Write Multiple Coils MBh = a, 15, t, b, array [ ]
16 Write Multiple Registers MBh = a, 16, e, r, array [ ]
17 Report Slave ID MBh = a, 17, array [ ]
Argument Description Argument Description
a Slave address h Connection handle number
array [ ] Name of array containing data r Number of registers
b Number of bits s 16 bit value
c 0 or 1 (to turn coil OFF or ON) t Starting bit number
e Starting register y Number of bytes
g Register number