AB ControlLogix BSL Question

[Cydog 0]

Good Morning , I am somewhat familier with the shift registers in the older AB plc's. Could you explain a couple of things dealing with the BSL in ControlLogix. What an example of the Array , Control , Source Bit , Length. Let me explain what I am doing. I have a part on a chain that I am looking for with a sensor ( input ). This part of the chain that I am sensing the part is about 3 steps away from the process that I would like to take place. For example, If I see the part at that position I would like for this seen part ( as a 1) step thru to that position 100 , 010 , 001. I have 27 positions on this chain ( would that be the Length?) BSL Bit Shift Left Array - Control - Source Bit - Length- Thanks in advance,

[Chavak 2]

Hi, In control logix it is similar to the older version, Array - Is the word address where you shift the bits. It have to declared as an array (that is the only difference). Say for example you declare a "Dint" datatype called My_Shift_Register as your array, In the Dimension 0 box set a value greater than 0, thus it becomes an array. So your bit address will become My_Shift_Register[0].0 to My_Shift_Register[0].31 for the first array word. To trace 27 positions you only need an array size of one. Control Bit - Previously known as 'R6' or 'Rn' in SLC - create a tag with a data type of 'Control'. That's it. Length - is the number of bits it needs to be shifted - you can set it as 32, to let it shift is one dint word. Regards _______