Example Application Write Program - Allen-Bradley 1771-DA User Manual

Ascii i/o module
Table of Contents

Advertisement

Appendix A
Example Application Write
Program
Use this application write program (Figure A.9) to display messages
containing current values from an intelligent I/O module.
The processor stores current values in a file, 500-505. The source of the
file could be read block transfers from an intelligent I/O module. The
processor writes messages to the ASCII module for display on an
industrial terminal using storage file 400-47, and write block transfer file
200-250. The storage file contains words for positioning current value
data on the screen, and words which store ASCII characters of your
message. The program moves current values, words 500 thru 505, into
appropriate locations in the storage file. The scan counter controls the
frequency at which write block transfers update the display.
If you want to demonstrate the use of this program to display messages,
load data into storage file 400 (Table A.A). In this example, the message
contains an 8-digit position number for each of three axes. Enter ASCII
characters of your message, message positioning codes, and example
8-digit position numbers for each axis. Load initialization data into file
200 (Table A.B). Refer to section titled "Formatting a Multi-Line
Message" (P. 3-24), for an explanation of data in the storage file.
This program will display current values if you add the source of current
data. This could be a read block transfer instruction that transfers current
value data from an intelligent I/O module into words 500 thru 505. Or, it
could be a file move instruction that moves current values into words 500
thru 505 from elsewhere in the data table.

Advertisement

Table of Contents
loading

Table of Contents