Rockwell Automation 1746-BAS BASIC LANGUAGE - Manual (Page 218)

Publication 1746-RM001A-US-P
13-28 Input Functions
The SLC processor must not set, then reset, the output file word 0, bit 12 on the
same ladder logic scan cycle. If this occurs, the module may miss the bit being set.
This CALL is active until it is re-executed with different input parameters. If this
occurs, the previous CALL 118 is automatically disabled and the new CALL 118
takes effect. Multiple CALL 118s are not executed in parallel.
This CALL has five input arguments and one output argument.
The first input argument enables or disables the CALL:
•
0 – Disable the previously executed CALL 118
•
1 – Enable the CALL. The following commands are acceptable:
– –– – PLC (Unprotected writes)
–
–– – PLC (Word range writes)
–
–– – PLC (Typed writes)
–
–– – SLC 5/02 (Unprotected writes)
–
–– – SLC 5/02 (Typed writes)
If the data received exceeds the string length or CPU file size, the remaining data is
truncated.
The second 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 the internal string (2) is chosen, the input/output image data handshaking bits
(word 0, bit 12) are not used to indicate that data was received by the module. In
the BASIC program, you must monitor the second character of the string
(transaction number) which is incremented upon every successful data transfer.
Then you must remove the data from the string before the next data packet is
received or data will be lost.
The third input argument is the word offset within the destination CPU file. This
offset points to the first word which contains the byte count of the valid data that is
transferred. The offset for the internal string is always 2. The byte count is placed at
character location 0, and location 1 is a transaction number that is incremented
upon every successful packet completion.