UT61E serial comms, can't make it work - Page 1
Forum section: electronics / testgear

author: cskilbeck
author_rank: Contributor
timestamp: January 14, 2017, 11:04:02 am
content: I'm trying to get my UT61E to talk to my PC and not having much luck.This blog post by Antonhttp://blog.avrnoob.com/2014/03/uni-t-ut61e-rs232-serial-interface.htmlsays the DTR and RTS lines need +12v and -12V, but I have no serial adapter which can supply that. His mod (which makes it work with a 3.3v supply) looks great, but I don't really want to hack the interface dongle up. Can anyone suggest a USB converter cable which works with the UT61E?Thanks,Charlie.

author: SingedFingers
author_rank: Frequent Contributor
timestamp: January 14, 2017, 12:54:50 pm
content: I couldn't get mine working with a USB dongle. I tried three different ones. It does work with my desktop however without one straight into a serial port.

author: Avacee
author_rank: Unknown
timestamp: January 14, 2017, 01:21:10 pm
content: I had no luck with the converters listed in another thread on here:https://www.eevblog.com/forum/testgear/ut-61e-rs232-usb-chipset-worked-and-chipset-that-failed/Search for a UNI-T UT-D04 Infrared USB Cable ... £9 on eBay.Edit: or you can get a Serial to PCI/PCI-X card - though make sure you get one which supports your OS.

author: cdev
author_rank: Super Contributor
timestamp: January 14, 2017, 02:41:57 pm
content: There is a USB cable for the UT 61 series , and they are pretty inexpensive.

author: cskilbeck
author_rank: Contributor
timestamp: January 14, 2017, 03:24:11 pm
content: Thanks for the replies, I do have a USB cable on order, but I'd like the serial one to work so I can integrate with my own software for logging (or is it peanuts to read the data through the USB dongle? I have no idea how to go about that..)

author: SingedFingers
author_rank: Frequent Contributor
timestamp: January 14, 2017, 04:43:11 pm
content: It probably comes up as a serial port when you plug it in.

author: tronde
author_rank: Frequent Contributor
timestamp: January 14, 2017, 05:01:54 pm
content: I think you can use a MAX232 connected between the original RS232 connector and the serial-USB. The original interface uses RTS and DTR to supply the circuit. Pin 2 on MAX232 is DTR (V+) and pin 6 is RTS (V-) if I am right. Ask google for examples of MAX232 and USB. The original circuit is RS232 with positive and negative voltage. Serial to USB is usually only poistive or 0V (TTL-serial). MAX232 Will give you V+ and V- in addition to the level convrsion between RS232 and TTL-serial used by the serial-USB converter.Else you can just use the IR led with a series resistor and a 40106 schmitt-trigger and feed the output to the serisl-USB converter. 40106 works fine on 3V.If lucky, you don't need the 40106 either. Just resistor, led and serial-USB.

author: Sairus
author_rank: Contributor
timestamp: January 14, 2017, 09:39:31 pm
content: Just use one of this (~3$ )

author: SingedFingers
author_rank: Frequent Contributor
timestamp: January 15, 2017, 10:55:14 am
content: They don't work.

author: TheoB
author_rank: Regular Contributor
timestamp: January 15, 2017, 12:09:13 pm
content: It will not work with a terminal emulator if the DTR and RTS are not configured. With Putty I could not get it to work unless manually powering those lines. But using an application that supported the UT61E did work.

author: thisguy
author_rank: Contributor
timestamp: January 15, 2017, 12:27:45 pm
content: Quote from: cskilbeck on January 14, 2017, 11:04:02 amThere is a less intrusive mod described in a comment further down on that page (UnknownNovember 16, 2015 at 12:56 AM). It will make it work at TTL levels without hacking up the dongle. It requires inverting the signal, but that can be done with a single transistor instead of the inverter chip suggested in the comment.

author: cdev
author_rank: Super Contributor
timestamp: January 15, 2017, 12:49:56 pm
content: I have several RS232 converters and one seems to work with my UT 61E as far as I could tell by sniffing the serial port once.But I never successfully ran the meter under Linux (wine) for some reason possibly unrelated.I think the supplied software launched fine under wine.I have a real serial port on my computer now so I should revisit it.

author: cskilbeck
author_rank: Contributor
timestamp: January 15, 2017, 07:06:34 pm
content: Quote from: thisguy on January 15, 2017, 12:27:45 pmThis looks perfect, thanks!

author: cskilbeck
author_rank: Contributor
timestamp: January 17, 2017, 07:02:36 pm
content: I've gone with one of these in the endhttp://www.onsemi.com/pub_link/Collateral/MC74HC1G14-D.PDFSeems to do what the datasheet says, just need to make up a cable with it in, thanks for your help.