HP 3478A voltage problem  - Page 1
Forum section: electronics / general

author: eevblogfan
author_rank: Frequent Contributor
timestamp: March 20, 2012, 01:52:14 pm
content: helloI recently purchase HP-3478A , he didn't arrive yet , but I noticed that he need 100V input voltage , in Europe we have 220~240V ,is it really critical , either 100V or 110V ? or 120V maybe ?the power rated is 25VA , can I harm the meter by feeding him 110V ?thank you in advance and I am sorry If my questions looks a bit silly .

author: tekfan
author_rank: Frequent Contributor
timestamp: March 20, 2012, 03:11:58 pm
content: If you are unsure which voltage the meter is set up for then you will have to open it up.Look at page 17 and 18 of the service manual:http://cp.literature.agilent.com/litweb/pdf/03478-90008.pdfIt will tell you how to change the line voltage and frequency.

author: eevblogfan
author_rank: Frequent Contributor
timestamp: March 20, 2012, 03:46:07 pm
content: heythank youthe meter is set to 100V .there is100V-120V-220V-240Vtherefor I asked , near the 100V there is black dot (and near the other the dot is empty )so I thought that if they bother to separate between 100V and 120V (instead of writing " (1)-100~120 , (2)-220~240 " ).and I really prefer to don't open the meter , I get it calibrated , I'll not open it .edit :>I saw , you ment 1 , 27~28 ,well , based on the datasheet , I need option "335" ,(220V@50Hz)the next question will be , how do I set it ?throo the serial connector (and computer ofcors) ?ther's any sort of program I need to download ?what do I need to know in order to "re program" the meter ?thank you in advance !

author: Unknown
author_rank: Unknown
timestamp: March 20, 2012, 05:35:57 pm
content: Quote from: eevblogfan on March 20, 2012, 03:46:07 pmI would set it to 120 V if you feed it '110 V'. The 110 V is likely to be close to 120 V anyway in most countries.Quote from: eevblogfan on March 20, 2012, 03:46:07 pmTry engaging your brain instead of mindlessly following procedures. What effect would changing the taps have that would not occur by feeding it a different input voltage? Did you get it calibrated so you can be confident in the results or to satisfy some paperwork?Quote from: eevblogfan on March 20, 2012, 03:46:07 pmChange the transformer connections and frequency selector as stated on pages 17-18 (2-1 to 2-2) of the linked PDF.Quote from: eevblogfan on March 20, 2012, 03:46:07 pmDoes this meter have any kind of serial interface? GPIB is parallel, as far as I know, . You reprogram the meter by changing the connections as mentioned above and changing the label with a Sharpie marker. This, and the correct line cord, is all the option meant.

author: Monkeh
author_rank: Super Contributor
timestamp: March 20, 2012, 05:45:32 pm
content: There is no way to avoid opening the meter. Changing the input voltage is not a software change, it is a physical electrical change to select the tap on the transformer. You should also change the fuse appropriately.You may want to confirm your line voltage, as it has different taps for 220VAC and 240VAC for a reason.

author: eevblogfan
author_rank: Frequent Contributor
timestamp: March 20, 2012, 06:16:12 pm
content: heythank youif you mean the switches below the " EXT TRIG " , well , it's address stuff , not input voltage selection ,and about the tap on the transformer , well , I don't know if he has taps .is someone know this meter from the inside ? can he/you tell me ?thank you in advance !

author: tekfan
author_rank: Frequent Contributor
timestamp: March 20, 2012, 06:29:26 pm
content: Again, please read pages 17 and 18 of the manual. It will tell you everything on how to change the line voltage and frequency.To set the voltage you need to open the meter. You won't damage the calibration in any way if you just open it and move the wire.To set the line frequency from 60 to 50Hz you only need to change the first switch on the back of the meter to the ''1'' position.

author: Monkeh
author_rank: Super Contributor
timestamp: March 20, 2012, 06:29:56 pm
content: Quote from: eevblogfan on March 20, 2012, 06:16:12 pmThere is a frequency selection you will need to make.QuotePlease read the service manual linked above.QuotePlease read the service manual linked above.

author: eevblogfan
author_rank: Frequent Contributor
timestamp: March 20, 2012, 06:55:54 pm
content: heyomg , I guess I was really drunk ><"now I notice the fig 2.2 and I assume that the only thing I should be worried about is the tax (16%) for the meter purchasethank you for been patience for my silly questions