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Calculating power consumption for PLC I/O signal module

Created by: EULER1313 at: 2/27/2014 12:38 PM (5 Replies)

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2/27/2014 12:38 PM	Rate (0)
EULER1313 Posts: 86 Rating: (1)	Hi All, Kindly I need your help for determining the right way to calculate the total power consumtion for S7-300 I/O signal modules (DI,DO,AI and AO modules). for example, how to calulate the total power consumption for "Digital input module SM 321; DI 32 x DC 24 V; (6ES7321-1BL00-0AA0)" according to the following info mentioned in its data sheet (find it atatched): Current consumption • From the backplane bus=Max. 15 mA Power loss of the module=Typ. 6.5 W Sensor selection data Input voltage • Rated value=24 VDC • "1" signal=13 V to 30 V • "0" signal=- 30 V to + 5 V Input current • "1" signal=Typ. 7 mA Thanks in advance Attachment SM 321; DI 32 x DC 24 V - datasheet.pdf (1619 Downloads)
EULER1313 Posts: 86 Rating: (1)
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3/1/2014 4:37 PM	Rate (2)
Aret Posts: 2348 Rating: (264)	Well, you wrote all the data needed: 7 mA per channel. If all channels are "1" you spend 732 = 224 mA. Also module electronics consume some power = 15 mA. So current consumption total = 239 mA. At 24V you get 0,23924 = 5,736 W. Manual gives 6,5 W (maybe beacause of peaks), i choose highest of 2 numbers when i count power consumption.
Aret Posts: 2348 Rating: (264)
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3/2/2014 8:34 AM	Rate (0)
EULER1313 Posts: 86 Rating: (1)	Thank you Aret for your concern, I think the power consumed through the backplane bus should be (15 mA5 VDC) because the voltage of backplane bus is 5 VDC. so the total power consumtion would be (7mA32 channel24 VDC+15 mA5 VDC= 5.451 W). but I was wondering if the power loss of the module 6.5 W shall be chesed as the highest power or shall be added to 5.451 to calculate the total power consumption of the module? Also I need to know how to calculate the total power consumption for the other DO,AI and AO modules.
EULER1313 Posts: 86 Rating: (1)
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3/6/2014 9:09 AM	Rate (0)
EULER1313 Posts: 86 Rating: (1)	Any suggestions?
EULER1313 Posts: 86 Rating: (1)
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11/30/2016 4:50 AM	Rate (1)
Sannty Posts: 1 Rating: (1)	EULER1313 Thank you Aret for your concern, I think the power consumed through the backplane bus should be (15 mA5 VDC) because the voltage of backplane bus is 5 VDC. so the total power consumtion would be (7mA32 channel24 VDC+15 mA5 VDC= 5.451 W). but I was wondering if the power loss of the module 6.5 W shall be chesed as the highest power or shall be added to 5.451 to calculate the total power consumption of the module? Also I need to know how to calculate the total power consumption for the other DO,AI and AO modules. Someone should kindly help in answering this question.
Sannty Posts: 1 Rating: (1)
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3/21/2017 5:32 AM	Rate (1)
Sienerd Posts: 3 Rating: (1)	The following I think the power consumed through the backplane bus should be (15 mA5 VDC) because the voltage of backplane bus is 5 VDC. so the total power consumtion would be (7mA32 channel24 VDC+15 mA5 VDC=5.451 W). but I was wondering if the power loss of the module 6.5 W shall be chesed as the highest power or shall be added to 5.451 to calculate the total power consumption of the module? 1) Actually you are multiplying directly 15ma with 24 VDC but 15ma is to convert into Amp first than you have to multiply it with 24 VDC. i.e. 0.015Amp24VDC= 0.36W 2) Further, 7ma32 CH= 224 ma, 0.224Amp24VDC=5.376W Thus, 5.376W+0.36w=5.736W, Thus 6.5W is taken for safer side*
Sienerd Posts: 3 Rating: (1)
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