Schneider Electric LXM32M manual Examples, Example of Function Code

LXM32M 3 Basics

3.4.6Examples

3.4.6.1 Example of "Function Code" 3

Reading an error memory entry. Since the Modbus addresses of the parameters of an error memory entry are contiguous (ascending order), a single Modbus request is sufficient.

Parameters _ERR_number (15362), _ERR_class (15364), _ERR_time (15366) and _ERR_qual (15368).

Modbus request Structure of the Modbus request:

Field	Bytes	Value	Meaning
Function Code	1	3	Read Multiple Registers
Starting Address	2	15362 (3C02h)	Address of the first parameter to be read
Quantity Of Regis-	2	8	Number of the 16 bit values to be read = 8
ters

Modbus response Structure of the positive Modbus response:

Field	Bytes	Value	Meaning
Function Code	1	3	Read Multiple Registers
Byte Count	1	16	Number of bytes: 8 bytes of data
Registers Value	16	32 bit value	_ERR_number, 15362 (error number)
		32 bit value	_ERR_class, 15364 (error class)
		32 bit value	_ERR_time, 15366	(error time)
		32 bit value	_ERR_qual, 15368	(error qualifier)

3.4.6.2 Example of "Function Code" 16

Writing of the software limit switches. Since these parameters also have consecutive addresses, a single Modbus request is sufficient:

Parameters MON_swLimP (1544) and MON_swLimN (1546).

Modbus request Structure of the Modbus request:

Field	Bytes	Value	Meaning
Function Code	1	16	Write Multiple Registers
Starting Address	2	1544 (608h)	Address of the first parameter to be written
Quantity Of Regis-	2	4	Number of parameters = 4 (8 bytes of data)
ters
Byte Count	1	8	Number of bytes: 8 bytes of data
Registers Value	8	32 bit value	MON_swLimP, 1544
		32 bit value	MON_swLimN, 1546

Modbus response Structure of the positive Modbus response:

01.2012
	Field	Bytes	Value	Meaning
V1.01,	Function Code	1	16	Write Multiple Registers
	Starting Address	2	1544 (608h)	Address of the parameter
0198441113843,	Quantity Of Regis-	2	4	Number of parameters = 4 (8 bytes of data)
	ters

Modbus-TCP module 33