7/6/2023 10:54 PM | |
Joined: 9/27/2006 Last visit: 7/14/2024 Posts: 12268 Rating: (2675) |
Hello utilisateur22; When you are using analog input modules with a S7 CPU, the A/D converter in the input module always presents you with numerical values between 0 and 27648, for unipolar values, or -27648 and +27648, for bipolar input values, whatever the resolution of the analog input module. This is all well explained in the S7-300 Module Data manual, in chapters 5, Principles of analog modules. Different analog module connections and parameters are described in Chapter 6: https://support.industry.siemens.com/cs/ca/en/view/8859629 Once you have decided to use the Scale function (FC 105), all you have to do is to connect the reading from the analog module (its address, generally in PIW___ format), indicate the limits you want to use, in your case 0.0% to 100.0%, specify if the signal is bipolar or not, and obtain the result in REAL format at the MD___ address (or DB register) you specify. FC 105 is used to read and scale an analog input signal to the PLC. FC 106 is used to unscale a signal from the PLC's analog output module to the field device, such as a drive speed command. For a more compact explanation, just read this article: https://program-plc.blogspot.com/2015/09/how-to-use-fc105-scale-and-fc106.html Hope this helps, |
Last edited by: dchartier at: 07/07/2023 10:03:18 |
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