Varec 4000 manual Integer Data, Host Request, ATT Response

Modbus Implementation Tank Gauge Transmitter

Note! In all of the following communication examples, the error check value is dependent upon the mode of transmission.

9.5.1Integer Data

The integer data is a whole number between 0 and the maximum Modbus integer (inclusive). The maximum Modbus integer is a user-configurable variable that is a whole number between 0 and 65,535 (inclusive). The integer data must also be scaled for each data type by entering the desired units, a minimum, and a maximum value. In order for the integer value to be correctly interpreted, these scaling factors must match the format expected by the host system. Scaling of the integer parameters is accomplished through floating-point registers or by using the Model 1200 Handheld Interface.

The following communication example shows the request for one register starting at register 0 (0000 Hex).

For the following example, assume:

•minimum = 1 meter

•maximum = 15 meters

•maximum Modbus integer = 65,534

Host Request

Address	Function	Start Reg	Start Reg	# of Reg	# of Reg	Error
	Code	H	L	H	L	Check
01	03	00	00	00	01	XX
ATT Response
Address	Function	Byte	Data	Data	Error
	code	Count	MSB	LSB	Check
01	03	02	41	24	XX

48 Installation and Operations Manual