I've run across this situation twice now and not sure why it is happening, but I'm sure I am not the only one to see this before and maybe someone can help me avoid it in the future.
I have a drive setup for 5 different preset speeds & ramps using a combination of 3 preset inputs from a Micrologix 1000. Program controlling is a basic grafcet step by step program with a few comparison and timing bits controlling the outputs for when the different speeds are required.
What is happening is that the rung is going true on the first run sequence on this motor but the output isn't, I can force the output, but I can't even toggle the bit. It's not latch unlatch the rung goes true and the program can't move on until this step is complete so it sits in the true with output remaining false. I thought maybe it was being given run condition in two spots at once but it isn't and I'm a little lost as to why the output won't go "high" when the rung is true in this case.
Any thoughts are appreciated.
I have a drive setup for 5 different preset speeds & ramps using a combination of 3 preset inputs from a Micrologix 1000. Program controlling is a basic grafcet step by step program with a few comparison and timing bits controlling the outputs for when the different speeds are required.
What is happening is that the rung is going true on the first run sequence on this motor but the output isn't, I can force the output, but I can't even toggle the bit. It's not latch unlatch the rung goes true and the program can't move on until this step is complete so it sits in the true with output remaining false. I thought maybe it was being given run condition in two spots at once but it isn't and I'm a little lost as to why the output won't go "high" when the rung is true in this case.
Any thoughts are appreciated.