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EnBomp
Joined: 13 Feb 2008
Posts: 5
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 19 Jun 2008 1:58 Measuring |
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hey all,
i've got the siemens step7-200 cpu 222 & the analog to digital extension EM 231 and i've a task to do which is to measure the voltage and current flowing in my local network of electricity and to draw their wave forms which needs very high accuracy as the frequency in the network is 50hz which means that 1 cycle of the voltage wave form takes 20msec. and we need to get all the points within 20 msec. so any help!!!???
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GLOBIS
Joined: 30 Jul 2005
Posts: 3
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| 23 Jun 2008 9:53 Measuring |
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I don't know very well step7-200, but if it integrate on it an analog input, so you can programm it to receive data and then convert it to digital every period ( depend on your precision). elsewhere you can interface an AD converter before your PLC and you will read data via your input pins and then do what ever you like.
Good luck
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kamelian_20
Joined: 01 Nov 2007
Posts: 24
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| 24 Jun 2008 7:19 Re: Measuring |
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hi
measuring voltage and current have so many ways easier than using a PLC.so now that you want to use a plc say clearly what your problem is?
you have PLC and also a analog to digital converter.and some waveform with priode of 20 ms.
if your problem is the sampling rate of extension card ?
or the problem is the scan time of the plc?take longer than on priode (exp:50 ms)?
tell your problem clear so may i could help you!!!
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