2920 Float & Tape Transmitter
MODBUSAppendix A — MODBUS Implementation
152
Installation and Operations Manual
Note
In all of the following communication examples, the error check value is depen-
dent upon the function code and message content.
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 minimum and maximum value. In order for the integer value to be
correctly interpreted, these scaling factors must match the format expected by the host
system.
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
Note
A formula for converting numbers to scaled integer format is provided below.
Calculating Integer Data
• Hexadecimal
representation:
4124
• Decimal equivalent: 16,676
The data returned for data address 0 is 16,676 (4124 Hex). This value must be scaled using the
following formula to give it meaning.
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
84 0A
2920 FTT Response
Address
Function
Code
Byte Count
Data
MSB
Data
LSB
Error
Check
01
03
02
41
24
88 0F
4.56 meters
Summary of Contents for 2920
Page 2: ......
Page 16: ...2920 Float Tape Transmitter 1 Introduction 6 Installation and Operations Manual...
Page 114: ...2920 Float Tape Transmitter 6 Bi Phase Mark 104 Installation and Operations Manual...
Page 120: ...2920 Float Tape Transmitter 7 MODBUS 110 Installation and Operations Manual...
Page 126: ...2920 Float Tape Transmitter 9 L J TankWay 116 Installation and Operations Manual...
Page 158: ...2920 Float Tape Transmitter 14 Ordering Information 148 Installation and Operations Manual...
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