Rockwell Automation 1746-BAS BASIC LANGUAGE - Manual (Page 224)

Publication 1746-RM001A-US-P
13-34 Input Functions
The seventh input argument is the message time-out value. This value (1 through
255) corresponds to the number of hundreds of milliseconds that are allowed to
receive the read response (0.1 through 25.5 seconds). If the read response is not
received within this time, the message aborts with the status equal to 55 in the
input file word 1, bits 0-7. If the time-out value is not within the range (1 through
255), the status POPped equals 2 and the transfer does not take place.
The eighth input argument is the selection of the destination CPU input image file
with or without the internal string, the CPU M1 file with or without the internal
string, or the internal string alone:
•
0 – CPU input image file
•
1 – CPU M1 file
•
2 – Internal string
•
3 – CPU input image file and internal string
•
4 – CPU M1 file and internal string
If you chose internal string (2), CALL 29 can be executed to initiate each data
transfer without requiring SLC processor interaction. The output file word 0, bit
10 will also initiate a string transaction.
The ninth input argument is the word offset within the destination CPU file. This
offset points to the first word transferred. The offset for the internal string is always
1. The first character (transaction number at location 0) is incremented on every
successful transfer, to inform the module that new data is in the string. The value of
the transaction number wraps around from 255 to 0.
If the CPU input image file is chosen, this offset must not be 0 or 1 because they
are reserved words. Zero is reserved for data transfer handshaking bits and word 1 is
reserved for the transaction status. A 0 or 1 causes an error to be POPped (2 - bad
input parameter) and the CALL is not executed.
If the data received exceeds the string length or CPU file size, the remaining data is
truncated.
The tenth input argument is the string number. If the eighth input argument does
not select internal string usage, the value of this input argument is ignored but
must still be PUSHed.