KerryP
Member
I am looking at a PLC5/80E progam with two FAL instructions in parallel on the same rung. The first instruction moves 10 elements of an integer file to another integer file. The source data is referred to by an indirect address. The Expression in the FAL is #N54:[N10:199]. The second FAL instruction moves 10 zeroes into the source mentioned above. The Dest for the second instruction is #N54:[N10:199] and the expression is '0'. Both instruction operate in ALL mode.
These FALs are part of a system to track parts into carriers and out of carriers along a plating line. The data refers to the part types and production codes. The integer locations represent the physical locations along the line or on the carriers. The data is supposed to follow the parts through the line from carrier to plating tank, to carrier and then into the next tank and so on.
Every now and then the part data gets dropped. Zeroes arrive in a location and then travel along with the part to the end of the line.
I suspect that the problem is order of operation/timing. My best GUESS is that the second FAL is completing before the first because of the indirect addressing.
These FALs are part of a system to track parts into carriers and out of carriers along a plating line. The data refers to the part types and production codes. The integer locations represent the physical locations along the line or on the carriers. The data is supposed to follow the parts through the line from carrier to plating tank, to carrier and then into the next tank and so on.
Every now and then the part data gets dropped. Zeroes arrive in a location and then travel along with the part to the end of the line.
I suspect that the problem is order of operation/timing. My best GUESS is that the second FAL is completing before the first because of the indirect addressing.