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about CPU 314 IFM

Created by: Damayanti at: 12/15/2012 11:26 AM (3 Replies)

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12/15/2012 11:26 AM	Rate (0)
Damayanti Bronze Member Joined: 10/17/2011 Last visit: 7/19/2022 Posts: 148 Rating: (3)	Dear Sir, I have CPU314IFM ( 6ES7314-5AE03-0AB0) I want to use onboard analog channels for measuring the temperature. I want to know, if i used 0-20mA transmitter for measuring 0 to 1000 degree celcious, in FC105, what will be LO_LIM and HI_LIM if i used 4-20mA transmitter for measuring 0 to 1000 degree celcious, what will be LO_LIM and HI_LIM Where to see, for what range, AI channel is configured? Warm regards, Damayanti
	Last edited by: O_Moderator at: 12/18/2012 9:08 PM new subject after splitting from /tf/WW/en/Posts/25029#top
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12/15/2012 1:26 PM	Rate (0)
dchartier Grandmaster-Expert Joined: 9/27/2006 Last visit: 9/19/2024 Posts: 12282 Rating: (2684)	Hello Damayanti; The SCALE function establishes a map (straight-line curve equation) between the incoming signal range and the output values (engineering values) you select. So,as in your example,as long as the input analog channels are correctly configured to accept either a 0-20 mA or 4-20 mA signal, then the LO_LIMIT and HI_LIMIT of the FC105 are simply the start and end values of the engineering units you want to show. In your case, 0.0 and 1000.0 (in REALfloating-point format). Note that if you are using the integrated I/Os of the CPU 314IFM you cannot use a 4-20 mA or 0-20 mA signal from the field (unless you use a signal conditionner): the 314IFM only accepts a bipolar +/- 20 mA signal (in which case your FC105 must be parametrized as BIPOLAR). This information comes from the following manual and is shown in the attachment: SIMATIC PLC S7-300, CPU Specifications CPU 312 IFM to CPU 318-2 DP Hope this helps, Daniel Chartier Attachment CPU 314IFM integrated IOs.jpg (212 Downloads)
	Last edited by: dchartier at: 12/15/2012 1:27 PM
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12/15/2012 2:22 PM	Rate (0)
Damayanti Bronze Member Joined: 10/17/2011 Last visit: 7/19/2022 Posts: 148 Rating: (3)	Dear Sir, Thank you. But I don't know about signal conditioners. Will you plz help in this regard. Now I have connected, 0 to 20mA signal of temp transmitter(without signal conditioner) and FC105 configured as Unipolar(ie Bipolar bit=0), and LO_LIM=0.0 and HI_LIM=1000.0 And, I am getting correct reading. in Hardware config. I am not getting description of AI channels of CPU314IFM. How to see it in STEP7 V5.5? Warm regards, Damayanti

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12/16/2012 3:56 PM	Rate (0)
dchartier Grandmaster-Expert Joined: 9/27/2006 Last visit: 9/19/2024 Posts: 12282 Rating: (2684)	Hello Damayanti; It has been so long that I worked with the CPU 314IFM that I cannot remember many details. It was discontinued around 2000, if I remember correctly, so... But I believe that you can select either voltage and current on the integratedanalog inputs simply by the way you wire your fieldinputs. There was no software configuration on these inputs in Step 7 v. 4, I do not believe the more recent versions would open additionnal configuration pages for this CPU. If you use a 0-20 mA signal on a +/- 20 mA input, and program the conversion as unipolar, then you will get adequate readings, but you will cut your input range and your resolution in half. If that satisfies you for the moment, you can work with it, but always remember that the error in your readings will be double that of a required signal. Hope this helps, Daniel Chartier

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