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| 11/15/2008 11:52 AM | |
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Posts: 100 Rating:
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I am new one in analog. i should make show the pressure transmitter value in mmi screen. i am using 0 - 70 bar PT. how can i display the pressure using current input(4-20ma) |
| 11/15/2008 1:55 PM | |
Joined: 9/27/2006 Last visit: 4/3/2025 Posts: 12345 Rating:
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Hello sundar; |
Last edited by: dchartier at: 11/15/2008 2:00 PM |
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| 11/25/2008 7:10 AM | |
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Posts: 100 Rating:
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Hi to all i have a doubt about scaling. i use also flow meter . the range (0 to 9 m3/hr). i am using unipolar (bipolar input is off)so the input integer value is assumed to be between 0 and 27648, i attached the program shapshot below. my question is 1) If the flow value 0m3/hr the input integer value is also should be minimum value(0) 2) If the flow value 9m3/hr the input integer value is also should be maximum value(27648) is it correct or not. The flow meter showing value comes in out as real. |
| 12/10/2008 4:47 AM | |
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Posts: 6 Rating:
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Hallo Sundar, For your question, in function SCALE maybe in the easy word i can explain like this : 4 mA is equal than 0 decimal 20 mA is equal than 27648 decimal and if you put range value output, for example, 0.0 - 100.0 so: 4 mA --> 0.0 20 mA --> 100.0 and if setting of your sensor 0 m3/h = 4 mA and 9 m3/h = 20 mA so 0 m3/h = 0.0 9 m3/h = 100.0 and yes, value output is real. I hope its help. Regard, Damha |
| 1/16/2009 9:06 PM | |
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Posts: 1 Rating:
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How do I compensate if the analog card is 8 bit? Does FC105 care what resolution the input signal is? |
| 1/17/2009 10:05 AM | |
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Joined: 9/27/2006 Last visit: 4/3/2025 Posts: 12345 Rating:
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Hello gerryh; The binary representation of an analog value from the periphery in Siemens PLCs is independant of the resolution of the analog module used. Whether your module is 8-bit or 16-bit, the numerical value of an analog input or outputwill always be represented from 0 to 27648 (unipolar value) or -27648 to +27648 (bipolar value). What will change is the internal resolution of the analog value, that is the steps that the value will take for an 8-bit module wioll be larger, while for a higher-resolution module the steps will be finer. If you need to convince yourself of this, please study the chapter on Analog Value Representation in the manual S7-300 Module Data: S7-300 Automation System Module data So, to answer your exact question, FC105 will scale the numerical value of the analog input to the engineering values you set, whether the module has an 8-bit resolution or 16-bit resolution. Hope this helps, Daniel Chartier |
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| 12/19/2009 9:13 AM | |
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Posts: 9 Rating:
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Dear dchartier You are right for analog signals for current and voltage measurement. But not true for all tyoes of signals, for example Pt100. In case of Pt100, the values range from -2000 to 8500. Though for Scaling purpose, the result will not be affected if properly parameterized. Thanks |
| 12/19/2009 1:58 PM | |
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Joined: 9/27/2006 Last visit: 4/3/2025 Posts: 12345 Rating:
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Hello ab1234; You are right, of course, about the PT100/1000 ranges. Notice in this case that the numerical value read in from the analog module only requires a division by 10 (best results are obtained if you convert the peripherical value to a REAL, and then divide by 10.0) in order to read the temperature. Refer to the manual proposed earlier for more details. Glad you pointed this out, Regards, Daniel Chartier |
Last edited by: dchartier at: 12/21/2009 9:11 PM |
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| 2/3/2010 12:50 AM | |
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Posts: 54 Rating:
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It should match the configuration at the back of the analog input and also set it right at the hardware configuration at the simatic manager then used the scaling blocks or you could write your own code for better understanding the scaling function |
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