I have been reading this site with great interest for a couple months. This group is a pretty amazing resource. I have particularly enjoyed the Siemens versus AB discussion because we were all AB and Automation Direct, until we recently bought a plant with Siemens controllers (or the Siemens knock off VIPA controllers).
This being my first post here, I thought I’d introduce myself and give you some background so you have an idea where I’m coming from. For the last ten years I’ve worked with injection molding machines as a process engineer for a pretty small company. With a small company you have to pick up many skills.
One of my first jobs was getting an old used molding machine working that ran off a PLC-2. I muddled through the basics of ladder logic while troubleshooting the machine and getting it running. Later I went and took a pretty good semester long course in PLCs at the local community college so I got an idea of what it was I had done two years earlier.
In my previous job, I did some minor programming, making some minor changes to trim presses, adding some functions, had to add some expansion modules to Micrologix 1200 but that was the extent of my active programming experience. After getting laid off earlier in the year, I recently started a job with a fair bit of programming time and am now getting into the field in depth.
Now for my question. In RS Logix 500, what’s the difference between the OSR and ONS commands. Both are triggered by a false to true change in the condition. Both will reset only after the conditions go false. I can’t see any functional reason to choose one over the other.
I am writing a program and want to make sure I don’t commit some stupid error using the wrong one, but both commands seem to work when I simulate the program.
Thanks in advance.
This being my first post here, I thought I’d introduce myself and give you some background so you have an idea where I’m coming from. For the last ten years I’ve worked with injection molding machines as a process engineer for a pretty small company. With a small company you have to pick up many skills.
One of my first jobs was getting an old used molding machine working that ran off a PLC-2. I muddled through the basics of ladder logic while troubleshooting the machine and getting it running. Later I went and took a pretty good semester long course in PLCs at the local community college so I got an idea of what it was I had done two years earlier.
In my previous job, I did some minor programming, making some minor changes to trim presses, adding some functions, had to add some expansion modules to Micrologix 1200 but that was the extent of my active programming experience. After getting laid off earlier in the year, I recently started a job with a fair bit of programming time and am now getting into the field in depth.
Now for my question. In RS Logix 500, what’s the difference between the OSR and ONS commands. Both are triggered by a false to true change in the condition. Both will reset only after the conditions go false. I can’t see any functional reason to choose one over the other.
I am writing a program and want to make sure I don’t commit some stupid error using the wrong one, but both commands seem to work when I simulate the program.
Thanks in advance.