Varec 4000 - Manual (Page 58)

Modbus Implementation Tank Gauge Transmitter
48 Installation and Operations Manual
Note! In all of the following communication examples, the error check value is dependent upon the mode of transmission.
9.5.1 Integer 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
Code
Start Reg
H Start Reg
L # of Reg
H # of Reg
L Error
Check
01 03 00 00 00 01 XX
ATT Response
Address
Function
code
Byte
Count
Data
MSB Data
LSB Error
Check
01 03 02 41 24 XX