4/20/2012 12:43 PM | |
Joined: 9/27/2006 Last visit: 9/21/2024 Posts: 12282 Rating: (2684)
|
Hello IT Service; There is a function in the instruction library nsamed FC 105 "SCALE" which you can usefor your purposes. You willfind it in the TI-S7 conversionsection of the instructions. It will take your input signal (a PIWxxx address) andscale it to anyengineering unit you need. http://support.automation.siemens.com/WW/view/en/1765297 This is only one of the many items you will find on the Search results if you look for FC 105 (see the Search box at the right of this page?). Try looking for the different posts and FAQs available if you need more information. Also take the time to look up the proposed link in this FAQ, as often Siemens (and forum members) will point to further information on the subject researched. In this case the link is to a very important manual, the S7-300 Module data manual, that has a very good chapter on analog signal representation. In order to use FC 105 properly, you must use the raw value of the analog input, either 0-27648 (Unipolar value) or -27647-+27648 (bipolar value). These values are how the S7 PLC digitalizes the signal that you have at the analog input channel. A 4-20 mA or 0-10V signal will be rrepresented in the PLC as a unipolar 0-27648 raw value. Sop the value that you place in the IN parameter of FC 105 is the PIWxxx address of your analog channel, as you have it defined in the HWConfig editor. FC 105 will allow you to convert that raw value to any limits you want. For a % value, put 0.0 and 100.0 as the LO_LIMIT and HI_LIMIT parameters (note that the limits are in REAL format, or floating-point if you prefer). The OUT resuslt will also be a REAL value, so try using a MDxx address for the result of the scaling operation.. If the raw value correspond to a 0-2500 GPM unbit, use 0.0 for tyhe LO-LIMIT and 2500.0 as a HI_LIMIT. As an example off what information you cna find on the forum, have a look at this exchange on scaling, our firend and forum member Ayman Elotaify has a attachment showing how to program FC 105 to get a 0-100% conversion of an analog input: /tf/WW/en/Posts/45069 Try it and tell us if you have need of more clatifications. Hope this helps, Daniel Chartier |
This contribution was helpful to1 thankful Users |
4/20/2012 5:50 PM | |
Joined: 4/22/2010 Last visit: 5/3/2024 Posts: 5697 Rating: (715)
|
Hello, Tosee what's behind the standard scaling blocks i have attached a S7-200 scaling function, taken from the Tips and tricks. The looks are a bit different as S7-300 but easy to understand(i think) Regards, Marcjan AttachmentTip038b.pdf (261 Downloads) |
Problem solved? |
|
4/23/2012 1:29 PM | |
Posts: 107 Rating: (0) |
Good day dchartier
Marcjan Yesterday I got a Book PRO1 as you mentioned and pointed it's very helpfull Thanks a lot.... Analog_Module and s7300_module_data_manual_en-US_en-US I'd looked Thanks for that additionally the interesting thing is that, when you got manuals and may be some books (like I'm)it's to hard to find something you need that's like a paradox ---- I know it'sridiculous but so it is --- so in this cases we (I)have to call for real specialists like you in order to get a bit experience from you... Thanks a lot and I'll look through the book. |
This contribution was helpful to1 thankful Users |
Follow us on