Module Operation - Automation Direct DL405 User Manual

8–8
F4–08THM–n 8-Channel Thermocouple Input

Module Operation

DL430 Special
Requirements
Before you begin writing the control program, it is important to take a few minutes to
understand how the module processes and represents the analog signals.
Even though the module can be placed in any slot, it is important to examine the
configuration if you are using a DL430 CPU. As you will see in the section on writing
the program, you use V-memory locations to extract the analog data. As shown in
the following diagram, if you place the module so input points do not start on a
V-memory boundary, the instructions cannot access the data.
Correct!
Wrong!
Data is split over two locations, so instructions cannot access data from a DL430.
V40401
MSB
X X X
3 3 2
7 0 7
F4–08THM–n
8pt 8pt 16pt 16pt
Input Input Input Input
X0 X10 X20 X40
– – – –
X7 X17 X37 X57
V40400 V40402
V40401
MSB
X X X
3 3 2
7 0 7
F4–08THM–n
8pt 16pt 8pt 16pt
Input Input Input Input
X0 X10 X30 X40
– – – –
X7 X27 X37 X57
LSB MSB
X X
2 1
0 7
16pt 16pt
Output Output
LSB
X
2
0
16pt 16pt
Output Output
V40400
LSB
X X X
1 7 0
0