Rockwell Automation 1746-BAS BASIC LANGUAGE - Manual (Page 194)

Publication 1746-RM001A-US-P
13-4 Input Functions
6. 6. 6. 6. The ladder logic program of the SLC resets output file word 0, bit 8 or bit 9.
The module can begin loading the destination buffer with the next packet as
data arrives from the port.
Data transfers continue until the CALL for the port is re-executed with different
input parameters. If this occurs, the previous CALL 22 for the port is automatically
disabled and the new CALL 22 takes effect. Multiple CALL 22s for the same port
are not executed in parallel. However, port 1 and port 2 can be activated
simultaneously by issuing separate CALL 22s.
This CALL has seven input arguments and one output argument.
The first input argument is the source port number (1 or 2) of the module. A zero
disables all previously active CALL 22 commands.
•
0 - Disable CALL 22 for all active ports enabled by earlier CALL 22s.
•
1 - Port 1 is source.
•
2 - Port 2 is source.
The second input argument is the maximum number of 8-bit characters to be
copied from the BASIC serial port to the destination file. The maximum number
of characters is selected by the fourth input argument:
•
CPU input image file: maximum characters - 10 (5 words)
•
CPU M1 file: maximum characters - 126 (63 words)
•
Internal string: maximum characters - string size-3 (The first character is the
byte count value; the second character is the incremented transaction number;
and the last character is the terminating character. The maximum number of
characters for an internal string is 254.)
If less than the maximum is acquired when a delimiter character is received, the
packet including the delimiter is sent to the CPU file. The SLC processor
determines the amount of valid data transferred into the destination file from the
byte count placed into the lower byte of the first word of the file.
If the data received exceeds the string length or CPU file size, the remaining data is
truncated.
SLC Processor SLC Backplane BASIC or BASIC-T Module
PORT PRT1
PORT PRT1
Reset Output File
Word 0, Bit 8 or
Bit 9