UT61E RS232 Linux Issues - Page 1
Forum section: electronics / testgear

author: Matt Hatter
author_rank: Contributor
timestamp: March 19, 2022, 01:00:38 am
content: I'm currently trying to read the raw serial data from the 61E's RS232 adapter. Having spent the better part of today bashing my head against the wall, I'll get to the point-I'm using a StarTech usb to 4 serial adapter (FTDI FT4232HL chipset). On windows I have no trouble using UNI-T's 61E software to log from the meter, so both the meter and adapter are functioning. However, I would strongly prefer to use my PI3B as I intend to use it to control/log from my other equipment.The FT4232HL adapter was identified by my linux distro without issue, and the 4 serial ports mounted to /dev/ttyUSB(*). Using CuteCom I am able to open each port and transmit data (the adapter has TX/RX LEDs for each port) but when I open the port connected to the meter and set it to 19200, 7, Odd, 1 I only get a break command.I tried a variety of other programs designed specifically for the 61E such ashttps://github.com/pklaus/ut61e_pythonwithout success. The aforementioned fails to find the device. If I am not mistaken, the 61E does not have an RX capability. Is this all just an awful linux driver mess? My RS232 and linux knowledge are both fledgling, but hopefully I haven't missed anything too obvious.

author: ledtester
author_rank: Super Contributor
timestamp: March 19, 2022, 01:40:08 am
content: Here's a thread that discussed communicating with the UT61E over a serial connection:https://eevblog.com/forum/projects/read-serial-data-from-uni-t-ut61e-dmm-using-linux/It also mentions using sigrok.

author: PKTKS
author_rank: Super Contributor
timestamp: March 19, 2022, 11:08:21 am
content: Things changed over time ...and if not enough... there is a know problem with CH34x kernel driver...which manifests itself when using this particular setupFOR THE RECORDMost UNI-T DMMs can be used with two (three) different PC interface cables:- The UT-D04 USB/HID cable, old version with Holtek HE2325U chip.- The UT-D04 USB/HID cable, new version with WCH CH9325 chip.- The UT-D02 RS232 cable.This driver is meant to support all USB/HID cables, and various DMMs thatcan be attached to a PC via these cables. Currently only the UT-D04 cable(new version) is supported/tested.The UT-D02 RS232 cable is handled by the 'serial-dmm' driver.This particular blurb identifies the CH34x driverCode:# New USB device found, idVendor=1a86, idProduct=e008# Product: USB to Serial# Manufacturer: WCH.CN ^T# hid-generic 0003:1A86:E008.0005: hiddev0,hidraw4: USB HID v1.00 Device [WCH.CN ^T USB to Serial] on usb-0000:02:00.0-1.3/input0The CH34x WCH.CN driver is known to have issues..Solution is to use FTDI chipset (or PLxxx more rare expensive)or... ditch them and use direct USB con. which works perfectlyaka D04 new cable type.. - works out of the boxPaul

author: myf
author_rank: Regular Contributor
timestamp: March 19, 2022, 01:42:26 pm
content: With my linux laptop, I use this short reset software in Python for uni-t ut-61 usb-interface :--------------------------------------------------------------------------------------#!/usr/bin/python3import usb.coreimport sysimport fcntlimport osUSBDEVFS_RESET = ord('U') << 8 | 20compl00 = lambda n : ('000'+str(n))[-3:]fd = Nonefor dev in usb.core.find(find_all=True, idVendor=0x1a86, idProduct=0xe008) :path='/dev/bus/usb/%s/%s' % (compl00(dev.bus), compl00(dev.address))fd = os.open(path, os.O_WRONLY)try:fcntl.ioctl(fd, USBDEVFS_RESET, 0)finally:os.close(fd)print ("port usb : %s/%s" % (compl00(dev.bus),compl00(dev.address)))if fd == None :print ("aucune interface uni-t")sys.exit(0)------------------------------------------------------------------------------------------------------------------And then I run sigrok without any problem.I hope this help you !You can post any question about you don't understand.F. (from France)