Figure 4.5, Figure 4.6, Variable area -6 – Rockwell Automation 900 Temperature Controller Communications Functions - Series B User Manual
Page 64: Addresses -6, Variable area, Addresses
Publication 900-UM004D-EN-E - July 2010
4-6
Modbus Communications Procedure
Variable Area
The variable area is the region of memory used to exchange data with the
900-TC8, 900-TC16, or 900-TC32 through communications.
Operations such as reading the process value and Reading/Writing parameters
are performed on the variable area.
On the other hand, operation commands do not use the variable area.
Figure 4.5
When accessing the variable area, the position of a variable in the variable area
is specified with a word identifier, area number, and address in the area.
Addresses
An address is appended to each of the variable types. Express addresses in
2-byte hexadecimal and append them for the specified access size. Each
address is composed of a word identifier, area number, and address in the area.
Figure 4.6
900-TC8 or 900-TC16
Microcomputer
Variable area
Read/write
Operation
commands, etc.
• Four-byte Mode
• Two-byte Mode
Address (2 bytes)
Area number (00 to 13)
Address in area (00 to FE): 128 variables
Word identifier (0 to 3)
Address (2 bytes)
Area number (20 to 33) Address in area (00 to 7F): 128 variables
Word identifier (0 to 3)
0 0 0 *
*
*
*
*
A
6
A
0
A
1
A
2
A
3
A
4
A
5
0
A
6
A
0
A
1
A
2
A
3
A
4
A
5
0 0
*
*
*
*
*
1