Hamilton Electronics EPHUM011 manual Configuration of the serial RS485 Interface, Device Address

pH ARC Sensors Modbus RTU Programmer’s Manual (EPHUM011)

2.3Configuration of the serial RS485 Interface

Factory settings of the RS485:

Parity is none, 1 start bit, 8 data bits, 2 stop bits (in total: 11 bits).

2.3.1Device Address

2.3.1.1Reading and Writing the Device Address

The sensor specific device address can be read and written in register 4096.

Start	Number of		Reg1 / Reg2		Modbus	Read		Write
register	registers				function code	access		access
4096	2		device address		3, 4, 16	U/A/S		S
Figure 2.3.1.1.1: Definition of register 4096.
Command: Com address				Modbus address: 4096			Length: 2		Type: 3	Read
Parameter:		Modbus address
Format:		Decimal
Value:		1

Figure 2.3.1.1.2: Example to read the device address.

The device address can be set by S (Specialist), default value is 1.

Command: Com address		Modbus address: 4096	Length: 2	Type: 16	Write
Parameter:	Modbus address
Format:	Decimal
Value:	3

Figure 2.3.1.1.3: Example to set the device address to 3.

2.3.1.2Reading the Device Address Limits

The device address limits can be read in register 4098.

Start	Number of		Reg1 / Reg2			Reg3 / Reg4	Modbus	Read	Write
register	registers						function code	access	access
4098	4		Min. device			Max. device	3, 4	U/A/S	none
			address			address
Figure 2.3.1.2.1: Definition of register 4098.
Command: Com address limits					Modbus address: 4098		Length: 4	Type: 3	Read
Parameter:		Min value		Max value
Format:		Decimal		Decimal
Value:		1		32

Figure 2.3.1.2.2: Example to read the device address limits: Min = 1, Max = 32.

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