Rockwell Automation 6008-SV2R VMEbus remote I/O Scanner - Manual (Page 173)

Chapter
Programming the Scanner
8
8Ć39
/* send the command interrupt */
assert_cmd(chan);
/* poll for command result */
if (wait_for_cmdcmpl(chan) == FALSE) {
/* clear the semaphore */
unlock_gda(chan);
unmap_channel(chan);
fprintf(stdout, ”continuous_bt: wait failure, lock cleared\n”);
return –2;
}
/* clear the semaphore & unmap channel */
res = csa–>cnfstat;
unlock_gda(chan);
unmap_channel(chan);
return (int) res;
}
A common VME control system using a scanner has the scanner
communicating with a PLC-5 processor set for adapter mode. In this
system, the scanner communicates with the PLC-5 processor over a remote
I/O link and the PLC-5 processor emulates a 1771-ASB module.
The PLC-5 processor in adapter mode has only local I/O. The rack
number of the adapter-mode processor determines the addresses you use.
Direct Transfer
You specify configuration files (output source file and input destination
file) in the adapter-mode processor If you want the scanner to control
outputs of the adapter-mode processor, write ladder logic in the
adapter-mode processor to move the data from its input destination file to
its output image table. Use XIC and OTE instructions for bit data; use
move and copy instructions for word data.
If you want the scanner to read data from a data file in the adapter-mode
processor, write logic in the adapter-mode processor to move that data to
its output source file for transfer to the scanner’s input image table.
The adapter-mode processor transfers 2, 4, 6, 8 words, depending on
whether it is configured as a 1/4, 1/2, 3/4, or full rack. For example, if the
adapter-mode processor is configured as a full rack, scanner and
adapter-mode processor exchange 8 input words and 8 output words each
I/O scan.
Important: Of the words that are transferred back and forth between the
scanner and PLC-5 processor, the first word in the input and output image
table contains rack status and block-transfer status. Don’t program any
data in these words.
Communicating with PLCĆ5
Processor in Adapter Mode