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G'day,
I'm new to this forum and to Step 7, so Hi to all and thx Siemens... What I'm trying to do is use 3 outputs on a card as a BCD to another device. I'm getting some obvious issues and would like to find out the best way to overcome them.
I'm using a S7-300 PLC and programming in statement list. I'm loading a decimal value, when an alarm happens, and transferring it to the output byte, which works well in the simulator. Now if I do this with the actual PLC... the rest of the card becomes useless because I'm writing to the whole card during my load and transfer statements, which means the other outputs are written to as well. I tried to make sense of the help file with the AW (and word) statement, as I have seen something like this before for "masking out" part of the byte so the rest of the card works for anyone else who comes along later and programs, but I couldn't do it. Is there an easier way? If not... Does AW work in a binary mode? Thx.
I'm new to this forum and to Step 7, so Hi to all and thx Siemens... What I'm trying to do is use 3 outputs on a card as a BCD to another device. I'm getting some obvious issues and would like to find out the best way to overcome them.
I'm using a S7-300 PLC and programming in statement list. I'm loading a decimal value, when an alarm happens, and transferring it to the output byte, which works well in the simulator. Now if I do this with the actual PLC... the rest of the card becomes useless because I'm writing to the whole card during my load and transfer statements, which means the other outputs are written to as well. I tried to make sense of the help file with the AW (and word) statement, as I have seen something like this before for "masking out" part of the byte so the rest of the card works for anyone else who comes along later and programs, but I couldn't do it. Is there an easier way? If not... Does AW work in a binary mode? Thx.