Instruction Manual

Chapter
5
5-1
Analog Block Applications Using
Discrete Transfers
In this chapter you will read about:
discrete data transfer
input data format
output data format
When used with SLC controllers, analog block data is transferred as
discrete data using the 1747-SN remote I/O scanner module. The analog
block uses 1/2 rack of memory in the I/O data table. The transferred words
in the input image data table contain only input data from the module.
Discrete transfer programming moves data from the module to the
processor’s data table in one I/O scan. The processor I/O scan initiates the
request to transfer data from the module to the processor.
The input image table data format consists of four words. All four words
are input data for the four input channels as shown in Table 5.A.
Figure 5.1
Discrete
Data T ransfer Description - Input T able 1/2 Rack
Decimal 15 14 13 12 11 10 09 08 07 06 05 04 03 02 01 00
Octal 17 16 15 14 13 12 11 10 07 06 05 04 03 02 01 00
0 Input Channel 0 Data
1 Input Channel 1 Data
2 Input Channel 2 Data
3 Input Channel 3 Data
Chapter Objectives
Discrete Data Transfer
Input Data Format