I notice that 12 V is mentioned. I measure ~6 V from ground to every pin except RxD, which is zero. (All DC; when not sending data.) Could this be the issue?
On Sun, Dec 10, 2017 at 6:28 PM, Denis Heidtmann <denis.heidtm...@gmail.com> wrote: > Here is the protocol description I recall finding: > > MAS345: > > data format: 7n2 at 600 baud (7 bits, no parity, 2 stop bits). > Control lines: > DTR and RTS lines are used to power the TX line: RTS is clear > for -12 supply; DTR is set for +12 supply. Data transmission is > solicited sending whatever character to the RX line. > Data string format: > MAS-345 sends a 14 bytes string with: > <mode>< ><sign><value>< ><units><return> > <mode>: two bytes with the oerating mode: DC, AC, OH, CA, TE ... > <sign>: one byte with - or space > <value>: five bytes with four digits and one decimal dot. > <units>: four bytes with the units: mV, A, kOhm, nF ... > <return>: '\r' > One space is inserted between <mode> and <sign>, one between > <value> and <units>. > The data string (without the '\r') is sent to the output device. > > On Sun, Dec 10, 2017 at 6:11 PM, Denis Heidtmann < > denis.heidtm...@gmail.com> wrote: > >> The protocol I recall seeing documented was 7n2, 600 baud. I must >> confess I do not know how to talk directly over serial. I tried Google, >> but there were too many options and opinions. What do you recommend for >> this simple task? >> >> On Sun, Dec 10, 2017 at 3:01 PM, Russell Senior < >> russ...@personaltelco.net> wrote: >> >>> Try talking to the DMM directly over serial. The protocol description >>> says: >>> >>> Various multimeters from Metex (and rebadged ones) use this common >>> 14-byte packet based ASCII protocol. The actual multimeter ICs in the >>> devices have different names (e.g. "MASTECH M343-01" or "Metex >>> KS57C2016") but they all use the same common protocol format. >>> >>> The serial port settings can vary from device to device, e.g. >>> 600/1200 baud, 7n2, RTS low, DTR high. >>> >>> If you get the serial parameters right, you ought to be able to talk >>> directly at it (e.g. send a D and get a string of bytes). Maybe you >>> can snoop the serial with an oscilloscope while running the vendor >>> interface software and figure out the baud,et al. >>> >>> On Sun, Dec 10, 2017 at 2:08 PM, Denis Heidtmann >>> <denis.heidtm...@gmail.com> wrote: >>> > Thanks for the -help. I got part of that -help when I entered an >>> incorrect >>> > option, but somehow missed the -- entries at the end. Here is what I >>> get: >>> > >>> > denis@denis-ThinkPad-L420:~$ sigrok-cli --driver >>> > mastech-mas345:conn=/dev/ttyUSB0 --scan >>> > The following devices were found: >>> > mastech-mas345 - MASTECH MAS345 with 1 channel: P1 >>> > >>> > denis@denis-ThinkPad-L420:~$ sigrok-cli --driver >>> > mastech-mas345:conn=/dev/ttyUSB0 --show >>> > mastech-mas345 - MASTECH MAS345 with 1 channel: P1 >>> > Supported driver options: >>> > conn >>> > serialcomm >>> > Supported configuration options: >>> > denis@denis-ThinkPad-L420:~$ >>> > >>> > Additionally I tried: >>> > denis@denis-ThinkPad-L420:~$ sigrok-cli --driver >>> > mastech-mas345:conn=/dev/ttyUSB0 --loglevel 5 >>> > sr: libsigrok loglevel set to 5. >>> > sr: backend: Sanity-checking all drivers. >>> > sr: backend: Sanity-checking all input modules. >>> > sr: backend: Sanity-checking all output modules. >>> > srd: libsigrokdecode loglevel set to 5. >>> > Usage: >>> > sigrok-cli [OPTION...] >>> > snip... >>> > >>> > I also tried the --output-file but nothing. I found that I could not >>> enter >>> > more than one option at a time---I tried --scan and --show but only the >>> > first one was responded to. >>> > >>> > BTW, recall that this instrument worked as expected using the vendor's >>> > windows sw on the desktop, where I have a serial port. So I do not >>> suspect >>> > the hardware outside the laptop. >>> > >>> > These results are encouraging, but no cigar. >>> > >>> > -Denis >>> > _______________________________________________ >>> > PLUG mailing list >>> > PLUG@pdxlinux.org >>> > http://lists.pdxlinux.org/mailman/listinfo/plug >>> _______________________________________________ >>> PLUG mailing list >>> PLUG@pdxlinux.org >>> http://lists.pdxlinux.org/mailman/listinfo/plug >>> >> >> > _______________________________________________ PLUG mailing list PLUG@pdxlinux.org http://lists.pdxlinux.org/mailman/listinfo/plug
