Integer interfacing enhancements, Write protect, Registers as unsigned integer – Rockwell Automation T8082 Trusted Toolset Suite User Manual
Page 69: Use two registers (32-bit), Least significant word first, Figure 52 extended attributes
Trusted
TM
Toolset Suite T8082
Issue 14 Feb 10
PD-T8082
69
6.5. Integer Interfacing Enhancements
There are four options for the Extended Attributes of analogue data. These control the manner in
which data is controlled and interpreted over Modbus communications. The options dialogue for
Extended Attributes is shown in Figure 52 below.
Figure 52 Extended Attributes
6.5.1.
Write Protect
Checking this option inhibits external communications from overwriting a data point. This applies to
both Integer/Real and Boolean variables.
6.5.2.
Registers as Unsigned Integer
Integer data is normally treated as 32-bit signed within the application (for signed data, the most
significant bit is used to distinguish positive and negative numbers). This option reads and writes
Modbus data as unsigned data.
6.5.3.
Use Two Registers (32-bit)
By default, only the lower 16 bits of an analogue data point are transferred to and from the Modbus
communications. This option uses two contiguous Modbus registers to transfer all 32 bits.
6.5.4.
Least Significant Word First
If ‘Use Two Registers’ is selected, by default the most significant 16 bit word is addressed first on
Modbus communications. This option reverses the words on the Modbus addresses.