Hello everyone and thanks for checking my post.
I’m a beginner in PLC programming (still in school) and I’m tasked with doing a monitoring of a pressure sensor and setting up an alarm at given value.
The trick is that the alarm value must be dynamic. The supervisor will modify it at will, with the PLC still running. For example, one day he can set up the alarm at 5000 PSI, the other day, at 7000 PSI.
The sensor outputs a 4-20mA analog signal with a range of 0-15000 PSI. If the value was static I’d have simply used an FC105 Unscale bloc and get done with the program.
However I think it’s not possible to set changing values only with the PLC (and a running one). Thus, I thought about making a little application on c++ (or c#) that will be hosted on PC and will overwrite the alarm value of the PLC through a physical link (Ethernet, I think).
I’ve done some research and found out about libnodave open source library. Labview appears, also, to be used. There’s Siemens’software, however I only done some direct programming through Simatic and never a real time overwriting through PC. And finally there’s the OPC server option but I have no knowledge about it
My questions are, I’m heading in the correct direction by choosing to overwrite values through PC? Is there other options to be considered and which are the easiest one to a beginner like myself with limited hardware?
And a bonus question, too, I’m hearing a lot about SCADA but my school offers no courses about it. Is there some good addresses to start learning (and possibly free ones) ?
Best regards.
I’m a beginner in PLC programming (still in school) and I’m tasked with doing a monitoring of a pressure sensor and setting up an alarm at given value.
The trick is that the alarm value must be dynamic. The supervisor will modify it at will, with the PLC still running. For example, one day he can set up the alarm at 5000 PSI, the other day, at 7000 PSI.
The sensor outputs a 4-20mA analog signal with a range of 0-15000 PSI. If the value was static I’d have simply used an FC105 Unscale bloc and get done with the program.
However I think it’s not possible to set changing values only with the PLC (and a running one). Thus, I thought about making a little application on c++ (or c#) that will be hosted on PC and will overwrite the alarm value of the PLC through a physical link (Ethernet, I think).
I’ve done some research and found out about libnodave open source library. Labview appears, also, to be used. There’s Siemens’software, however I only done some direct programming through Simatic and never a real time overwriting through PC. And finally there’s the OPC server option but I have no knowledge about it
My questions are, I’m heading in the correct direction by choosing to overwrite values through PC? Is there other options to be considered and which are the easiest one to a beginner like myself with limited hardware?
And a bonus question, too, I’m hearing a lot about SCADA but my school offers no courses about it. Is there some good addresses to start learning (and possibly free ones) ?
Best regards.
