For digital display output what should be the input

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Jaya Krishna Active Contributor Join Date: Oct 2007 Location: HYDERABAD, INDIA Posts: 21 Good Answers: 1	For digital display output what should be the input 10/25/2007 9:33 AM
	For a Digital display input given is 4 -20mA @ 230VAC. Then for the dispaly is only this 4 - 20mA sufficient for functioning or do we need to give a seperate DC power( 24V DC). __________________ One who is afraid to ask is ashamed to learn
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PWSlack Guru Join Date: Jan 2007 Location: In the bothy, 7 chains down the line from Dodman's Lane level crossing, in the nation formerly known as Great Britain. Kettle's on. Posts: 32175 Good Answers: 839	#1 Re: For digital display output what should be the input 10/25/2007 9:58 AM
	Some diplays are loop-powered devices, using the 4-20mA only. Some need a separate power supply. The original equipment manufacturer's manual will explain this in detail. From the description above and without being able to see the instrument it appears that the manual needs to be read more closely. Connecting 230VAC onto 4-20mA input terminals may result in and a subsequent need to replace the instument. Beka (among other suppliers) produce digital displays, most of which are loop-powered and do not use a separate supply. __________________ "Did you get my e-mail?" - "The biggest problem in communication is the illusion that it has taken place" - George Bernard Shaw, 1856
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Jaya Krishna Active Contributor Join Date: Oct 2007 Location: HYDERABAD, INDIA Posts: 21 Good Answers: 1	#3 In reply to #1 Re: For digital display output what should be the input 10/26/2007 1:06 AM
	Thanks for the clarification __________________ One who is afraid to ask is ashamed to learn
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cnpower Guru Join Date: Sep 2006 Location: CHINA Posts: 2945 Good Answers: 14	#2 Re: For digital display output what should be the input 10/25/2007 9:34 PM
	2 wire 4-20ma interface can offer power by itself converter inner. 3wire can be powered by host. depend on whichone you will select. read description details
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Vulcan Guru Join Date: Oct 2006 Location: Northern Mindanao, Philippines Posts: 2147 Good Answers: 53	#4 Re: For digital display output what should be the input 10/26/2007 1:49 AM
	There are displays that can operate with only the 4-20mA signal and there are displays that require a separate power supply. You'll have to determine that yourself. If the display that you have has just two terminals, it's a good bet that the instrument is loop powered (gets its power from the 4-20mA). If it has four or more, it may need a separate power supply. Note the "may" in the last sentence since the other terminals might not be power terminals. It might be easier if you could post a picture or give the brand and model of your display. Else, a more detailed description would be enough. __________________ Miscommunication: when what people heard you say differs from what you said. Make yourself understood.
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cnpower (1); Jaya Krishna (1); PWSlack (1); Vulcan (1)

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