Sequencer in PLC 5 AB


Thread Starter

Ricardo Juarez

Hello, I need make some sequencer output in my PLC 5 program but I can´t understand very well the instruction for do that. I read several times the help manual in RSLogix 5 about SQO and BSL or BSR instruction and try do that but my sequencer doesn´t work good.
My propouse is shift one Output at time using the bit S:23/0,.
If someone knows something, I appreciate your help.

John Paley--Graphic Pkg Corp

You want to do what????

What is the function of s:23/0? a clock?? If that's bit 0 of the free running clock, it's too darned fast to drive a bit shift instruction.

The bit shift left works like this.
There is a file--the shift file say #b18:0.
There is a control address, say r6;0
There is an address, say b3/0.
There is a length, say 16 bits.
There are cladder conditions--the BSL is an output function.

Every time the rung goes from false to true, the register shifts the bit values one spot to the left--the value, 1 or 0, of b10/0 goes to b18/1, 1 to 2, 2 to 3, and so on--and the value of the address is put into the first bit of the register b18/0 (the first bit of the register). Every time the rung goes true, the bits are shifted one, and bit 0 is loaded with the address bit. If there is a one at at the last position of the register, b18/15 because our lenght is 16 bits, and the rung goes true, a one is put into the controlword.UL bit (unload), or r6:0.UL.

I use them for jam detectors on non-timed folder gluer machines. I see a carton in the machine with an eye--address bit. I make the rung true with a 1 pulse per inch pulser riding on the conveyance belt. I have another eye at a jam point. The length is the distance between the eyes. When the bsl unloads, there should ba a carton under the second eye. If there's not, the carton didn't make it for some reason, and there's a jam. That was oversimplified, but that's basically what it does. The bsl tells the controller when to expect a carton in the real world.

I have to say that from your post, I don't know what you are trying to accomplish. I will say one thing, a BSL or BSR is closer to a FIFO of LIFO than a sequencer instruction. The fifo's shift words instead of bits and don't unload themselves.