Current logging - Page 1
Forum section: electronics / beginners

author: Seyar
author_rank: Newbie
timestamp: March 24, 2015, 03:55:05 pm
content: Hallo it is my first post to this community. Therefore first I would like to thank everybody who share their knowledge to help others.I am second year student of electrical engineering and I love to help others but now I need your help.My problem is that I want to measure current of one circuit for one whole day. So I think that I need a current logger. I have fluk 45, normaal should I can logging the current with that device, like in this linkhttps://www.flickr.com/photos/linux-works/6836666508/in/photostream/But I can't, I have male usb/db9 so i just connect Rx of fluke to Tx of usb/db9 and Tx to Rx, GND to GND and once i tried DTR to pin 1 and 6 and other time with out DTR. I thought that it should work but I can't communicate with fluke (fluke RS-232 have just 4 pin. GMD,DTR,Tx and Rx). I tried servel software for it like (putty, hyper terminal and RS232 data logger) but none of them worked. So i contact the fluke for support but they gave me advice to buy their software, but for student it is very expensiveand i am sure that someone can solve this problem.So can you please gave me advice how to connect my fluke 45 to computer? Of is their any other way to logging the current of circuit for one whole day?I am doing this to find how much current does this circuit wil need for one day.Thank you

author: katzohki
author_rank: Frequent Contributor
timestamp: March 24, 2015, 04:23:29 pm
content: Go download the manual and read through section 5 "Operating the Meter Using the Computer Interface." You should be able to communicate directly with the Fluke 45 over RS-232, so that means yes Putty or Hyperterminal should work assuming you have the COM ports set up correctly. If you're using USB to RS-232, sometimes it takes extra work to get it set up right. Start by sending the command over terminal*IDN?and see if it responds correctly.Edit: Make sure the RS-232 interface is enabled!

author: Electro Fan
author_rank: Super Contributor
timestamp: March 24, 2015, 04:49:01 pm
content: I think the first thing to do is to prove you can get your RS-232 port wired correctly to transmit and receive data. (I realize you are trying to receive data from your Fluke on your computer but working to get both TX and RX might help you get things setup.)As katzohki said, make sure you have the right COM port set.Then, for example if you have access to an oscilloscope, to send data from the HyperTerminal program all you need to do is to connect an oscilloscope probe to the TD (transmit Data) pin (Pin 3) of the DB9 (RS-232 port) connector on the computer and connect the scope probe's ground to the GND pin (Pin 5) on the DB9. Then set HyperTerminal for 2400 bps and turn flow control to None with 8 data bits, 1 stop bit, and parity None. You should be able to see the signal on a scope - with a Rigol or other scope that has decoding you can also decode the bytes and bits. If you only send a few characters it will be easier to catch the signal on a DSO rather than an analog scope but f you send a fairly long string of text (a page or two as a .txt file) it will be easier to see the signal on the scope. Once you confirm you are communicating properly between HyperTerminal and the RS-232 port on the transmit side you should be pretty close to being able to receive data as well. Use the RD (receive data) pin (Pin 2). Hopefully this will get you closer to being able to receive data from your Fluke.