JeffB
Lifetime Supporting Member
Hello Everyone,
I've been trying to expand my knowledge of the SQO instruction. I've got an A/B 5/04 set-up as a test rack, and I'm using RsLogix 500 release 5.20. First, let me explain what I've been able to accomplish. I've written and debugged the logic to "step up", "step down" and reset a sequence to "step 1". By using indirect addressing for the destination, I am able to go beyond 16 steps, and again, I'm able to manipulate the steps as necessary.
Now to the point of this post. Earlier today, I discoverd that if I left the bit I'm using to trigger the SQO, in state "1", the sequencer would cycle repeatedly throughout the steps. In the A/B help section of RsLogix, it states that a false to true transition is required to step to the next step. I ASSUMED that it meant one step for each false to true transition. Well, now here's where it gets weird, I inserted an OSR after my trigger, and it worked as expected.
But, during further edits, I removed the OSR, and now the SQO only steps one time for each false to true transition of the trigger. No matter how long the trigger stays high.
Can anyone tell me any reason why the behavior of the instruction has changed? Could it have anything to do with the index (S:24) value?
Thanks to all who take the time to read this long post. I'll be glad to send the file to anyone who might want to take a look.
I've been trying to expand my knowledge of the SQO instruction. I've got an A/B 5/04 set-up as a test rack, and I'm using RsLogix 500 release 5.20. First, let me explain what I've been able to accomplish. I've written and debugged the logic to "step up", "step down" and reset a sequence to "step 1". By using indirect addressing for the destination, I am able to go beyond 16 steps, and again, I'm able to manipulate the steps as necessary.
Now to the point of this post. Earlier today, I discoverd that if I left the bit I'm using to trigger the SQO, in state "1", the sequencer would cycle repeatedly throughout the steps. In the A/B help section of RsLogix, it states that a false to true transition is required to step to the next step. I ASSUMED that it meant one step for each false to true transition. Well, now here's where it gets weird, I inserted an OSR after my trigger, and it worked as expected.
But, during further edits, I removed the OSR, and now the SQO only steps one time for each false to true transition of the trigger. No matter how long the trigger stays high.
Can anyone tell me any reason why the behavior of the instruction has changed? Could it have anything to do with the index (S:24) value?
Thanks to all who take the time to read this long post. I'll be glad to send the file to anyone who might want to take a look.
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