PLC-5 BSL help

[CMP_elec]

Just a question about the BSL instruction in PLC-5. The details of the instruction in my program are: File #B3:11, Control R6:0, Bit Address B3:3/2, Length 16. Is the length (16) too long, and would it cause problems in the program?

It says in the help section for Length 'the total number of bits to be shifted by the BSL. Remember that bits in the I/O files are numbered in octal 00-17, but that bits in other files are numbered in decimal 0-15.' This is why I wonder if the length is set wrong.

Any help would be appreciated, Thanks

 

[Ken Roach]

The Length is fine; data file B3 is an ordinary PLC-5 data file, so data file element B3:11 has sixteen bits, numbered 0 through 15.

BSL's can be shorter or longer than a single 16-bit Word, but that's a very common implementation.

The "Bit Address" is the source address for the Bit value that is placed in the rightmost bit when the BSL is executed.

 

[CMP_elec]

Thanks Ken. Wasn't sure whether the 'Length' figure should be in the 0-15 range or 1-16. Thought this would be the easiest way to find out and I was right. Thanks again