Next in this saga:
I fashioned a breakout of the usb connector to see if the serial-to-usb
adapter was generating signals on the usb lines when the dmm was generating
signals on the rs232 lines. This may have been a fool's errand, as it
looks like there are constant pulses on the usb with 250 ns
Well, just in case...I wired a switched connector. That found no
communication:
denis@denis-ThinkPad-L420:~$ sigrok-cli --driver
mastech-mas345:conn=/dev/ttyUSB0 --samples 10
sr: serial: Didn't find a valid packet (read 0 bytes).
No devices found.
For completeness, here are the interface conditio
On Sat, Dec 16, 2017 at 3:48 PM, Denis Heidtmann
wrote:
> Yes, Russell, I thought of that. I first need to install the driver for
> the usb-serial device, recall how I did that on the laptop, and try to do
> it the same way. But I will pursue that when I get access to the desktop.
>
> Is there a
Yes, Russell, I thought of that. I first need to install the driver for
the usb-serial device, recall how I did that on the laptop, and try to do
it the same way. But I will pursue that when I get access to the desktop.
Is there a line on the usb that should be bouncing up and down when RXD is
On Sat, Dec 16, 2017 at 9:30 AM, Denis Heidtmann
wrote:
> With this new found knowledge I noticed that the interface was set for 1
> stop bit. I set it for two, as the protocol is reported to use. It made
> no difference in the behavior I observe--no response (other than the usual
> delay) to th
On Sat, Dec 16, 2017 at 9:30 AM, Denis Heidtmann
wrote:
> With this new found knowledge I noticed that the interface was set for 1
> stop bit. I set it for two, as the protocol is reported to use. It made
> no difference in the behavior I observe--no response (other than the usual
> delay) to t
With this new found knowledge I noticed that the interface was set for 1
stop bit. I set it for two, as the protocol is reported to use. It made
no difference in the behavior I observe--no response (other than the usual
delay) to the request for data.
Ideas? Should I look for/fabricate connecto
Denis,
In Unix-manpage-speak, [] around something means it's optional.
Regards,
NealS
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>From man stty:
[-]parenb
generate parity bit in output and expect parity bit in input
[-]parodd
set odd parity (or even parity with '-')
I thought the "-" preceded every control; not meaning negative. Your
interpretation makes more sense. The parodd entry an
Denis,
I believe "-parenb" means no parity, as shown in your stty -a output, looks
good to me.
I'm just guessing, not having anything serial or scope-ial to hook up to my
linux box at the moment.
The cooked/raw/echo/xyzzy settings are way beyond my scope of experience.
NealS
___
Galen, thanks for the Clinic offer, but I will not be able to make it
there.
Since my last report I have set the baud rate and bits:
denis@denis-ThinkPad-L420:~$ stty -F/dev/ttyUSB0 -a
speed 600 baud; rows 0; columns 0; line = 0;
intr = ^C; quit = ^\; erase = ^?; kill = ^U; eof = ^D; eol = ;
eol2
On 12/14/17 21:24, Denis Heidtmann wrote:
> Measuring with a 'scope with the laptop issuing the command sigrok-cli
> --driver mastech-mas345:conn=/dev/ttyUSB0 --samples 10:
>
> triggering on DTR
>
> DTR goes from -6.6V to +7.6V and remains there 'till 9.64s
> RX goes from -2.6V to +6.4V for .48s
Measuring with a 'scope with the laptop issuing the command sigrok-cli
--driver mastech-mas345:conn=/dev/ttyUSB0 --samples 10:
triggering on DTR
DTR goes from -6.6V to +7.6V and remains there 'till 9.64s
RX goes from -2.6V to +6.4V for .48s then again at 2.6s,3.12s, etc 'till
7.32s (10 groups of
The optocouplers in the dmm are reportedly TLV817B. The emitter resistor
on the output npn is shown on the schematic to be 1.5K. I measured it to
be 7.35K. The input resistor in series with the LED is listed as 3.3K. I
have not opened the dmm to see if the schematic is accurate. I agree that
t
On 12/13/17 23:03, Russell Senior wrote:
> The precise levels are not supposed to make a difference. Below a
> negative threshold and above a positive threshold should be enough.
> From memory, original RS232 was +/- 12V, but any remotely modern PC
> would use +/- 5V-ish.
And the reality is that
The precise levels are not supposed to make a difference. Below a
negative threshold and above a positive threshold should be enough.
>From memory, original RS232 was +/- 12V, but any remotely modern PC
would use +/- 5V-ish.
https://en.wikipedia.org/wiki/RS-232#Voltage_levels
What happens to D
To step back a bit I fabricated a little fixture to make it convenient to
test the lines going into the dmm. I found a description of those lines:
5-pin inline connector.
pin 1 Gnd
pin 2 TX
pin 3 RTS (must be off)
pin 4 DTR (must be on)
pin 5 RX
The connections are through optical couplers in the
On Mon, Dec 11, 2017 at 11:21 AM, Denis Heidtmann
wrote:
> Is it possible that your command /dev/ttyUSB0 600,cs7,cstopb,-parenb has an
> error?
Not only possible, but likely.
> I executed stty 600 then stty -a :
> denis@denis-ThinkPad-L420:~$ stty -a
> speed 600 baud; rows 24; columns 80; line =
Is it possible that your command /dev/ttyUSB0 600,cs7,cstopb,-parenb has an
error?
I executed stty 600 then stty -a :
denis@denis-ThinkPad-L420:~$ stty -a
speed 600 baud; rows 24; columns 80; line = 0;
intr = ^C; quit = ^\; erase = ^?; kill = ^U; eof = ^D; eol = ;
eol2 = ; swtch = ; start = ^Q; st
Tried it. No response. Not sure how I got back to a functioning terminal,
but now:
denis@denis-ThinkPad-L420:~$ sigrok-cli --driver
mastech-mas345:conn=/dev/ttyUSB0 --scan
sr: serial: Error opening port (16): Device or resource busy.
denis@denis-ThinkPad-L420:~$
On Sun, Dec 10, 2017 at 11:32 PM
The signaling on a PC RS232 line is +nV and -nV, where n is somewhere
between 5 and 12, inclusive. So, I think -6V would be a zero and a
+6V would be a one.
I think you can use GNU screen here, with the following options
(serial parameters are from the manpage from stty(1):
screen /dev/ttyUSB0
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
wrote:
> Here is the protocol description I recall finding:
>
> MAS345:
>
> data format:
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 whateve
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
wrote:
> Try talk
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 the
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
russell@vanhorn:~$ sigrok-cli --help
Usage:
sigrok-cli [OPTION...]
Help Options:
-h, --help Show help options
Application Options:
-V, --version Show version and support list
-l, --loglevel Set loglevel (5 is mos
The Fluke example certainly sends the data to the screen. The example the
sigrok site gave (sigrok-cli --driver mastech-mas345:conn=/dev/ttyUSB0
--samples 10) has --samples 10 tacked on. It is not clear to me which sw
reads that. I tried changing that to other stuff but I just get sigrok
help s
https://www.youtube.com/watch?v=TWwuiIfq_Z4
On Sat, Dec 9, 2017 at 6:19 PM, Russell Senior
wrote:
> I don't actually know what sigrok does, but I would naively expect it
> to blurt data out onto the screen. Time to go looking for helpful
> youtube videos.
>
> On Sat, Dec 9, 2017 at 6:17 PM, Deni
I don't actually know what sigrok does, but I would naively expect it
to blurt data out onto the screen. Time to go looking for helpful
youtube videos.
On Sat, Dec 9, 2017 at 6:17 PM, Denis Heidtmann
wrote:
> The loop-back worked. Running sigrok-cli --driver
> mastech-mas345:conn=/dev/ttyUSB0 -
The loop-back worked. Running sigrok-cli --driver
mastech-mas345:conn=/dev/ttyUSB0 --samples 10 w/sudo produced the same
result as earlier--a 10 second silent delay.
Should the results, ascii according to the protocol, appear in the terminal
used to launch the command?
On Sat, Dec 9, 2017 at 5:1
Try loopback on your usb-serial adapter. That is, connect pin 2 and
pin 3 (tx and rx, or vice versa). Then run something like:
screen /dev/ttyUSB0 115200
and type some letters on the keyboard and see if they echo back at
you. If so, the serial cable is working. If not, you might need a
diff
Some progress. I executed "sigrok-cli --driver
mastech-mas345:conn=/dev/ttyUSB0 --samples 10" forgetting that the meter
was not plugged into the adapter--got "sr: serial: Didn't find a valid
packet (read 0 bytes).
No devices found." Plugged in the meter, then got no response, but exactly
10 secon
The DMM won't show up in dmesg. All the OS sees is the serial port.
The sigrok cli thing should be able to find the DMM through the serial
port.
On Thu, Dec 7, 2017 at 7:48 PM, Denis Heidtmann
wrote:
> I did as suggested with the lsusb/dmesg. It looks to me that the adapter
> is detected but th
Is the USB-RS232 adapter known to work?
Several years back I had a no-name adapter. Couldn't get it to work. Found
out it had a fake Prolific chip in it. No wonder it had such an attractive
price.
Try looping it back to itself and see if it works before you go too far
down a rabbit hole. Possible
I did as suggested with the lsusb/dmesg. It looks to me that the adapter
is detected but the presence of the DMM into the adapter is not sensed.
Agree? Maybe it does not matter. Just proceed as if the DMM is seen?
denis@denis-ThinkPad-L420:~$ lsusb
Bus 002 Device 003: ID 5986:03b4 Acer, Inc
Bus
There is an example on the wiki page:
https://sigrok.org/wiki/MASTECH_MAS345
that says:
sigrok-cli --driver mastech-mas345:conn=/dev/ttyUSB0 --samples 10
I would try that. That might or might not be the right serial device
(i.e. ttyUSB0)... check dmesg, unplug/replug your cable and check
a
I agree completely. I have downloaded sigrok-cli. Now I have to try to
understand how to use it. (I feel a bit overwhelmed.)
Where do I put the driver? Is output/input with respect to the external
device or the software? I assume the device, judging by the longer list of
output formats. What i
The sigrok route is probably a better investment of your time than a
vendor-software horror show, imho.
On Wed, Dec 6, 2017 at 3:02 PM, Denis Heidtmann
wrote:
> here is the link:
>
> https://sigrok.org/wiki/Multimeter_ICs#Metex_14-byte_ASCII
>
> I would need to study it and educate myself on how
here is the link:
https://sigrok.org/wiki/Multimeter_ICs#Metex_14-byte_ASCII
I would need to study it and educate myself on how to make use of it.
-Denis
On Wed, Dec 6, 2017 at 2:29 PM, Denis Heidtmann
wrote:
> I have found this:
> Protocol
>
> The protocol is (partially) documented in the ve
It looks like it speaks the same protocol as the MAS345 which is supported
by Sigrok if you want to just use it under Linux.
https://sigrok.org/wiki/MASTECH_MAS345
On Wed, Dec 6, 2017 at 2:34 PM Russell Senior
wrote:
> I guess we should establish what you want to use this for? I may be
> presu
I guess we should establish what you want to use this for? I may be
presuming wrongly. My bias is usually towards capture into handy
formats I can manipulate easily with unix shell tools. Maybe that's
not at all what you want to do.
On Wed, Dec 6, 2017 at 2:29 PM, Denis Heidtmann
wrote:
> I have
I have found this:
Protocol
The protocol is (partially) documented in the vendor software's "Help"
window (seems to apply to MAS343, MAS344, and MAS345; the M9803R protocol
is different).
See Multimeter_ICs#Metex_14-byte_ASCII for the DMM IC protocol.
I looked in the software's help window, but
It looks this might be a starting point:
http://www.perlmeister.com/lme/prod-0710.pdf
On Wed, Dec 6, 2017 at 2:15 PM, Russell Senior
wrote:
> Have you googled at all about the protocol? You might be able to just
> talk ASCII at it from Linux and get what you need.
>
> On Wed, Dec 6, 2017 at 1
Have you googled at all about the protocol? You might be able to just
talk ASCII at it from Linux and get what you need.
On Wed, Dec 6, 2017 at 1:22 PM, Denis Heidtmann
wrote:
> I want to use a DMM with a serial connection. The sw for the DMM is for
> windows. It runs under Win2k (guest) on the
I want to use a DMM with a serial connection. The sw for the DMM is for
windows. It runs under Win2k (guest) on the desktop which has a serial
port. Is it possible to get it to run under Win2k (guest) on the laptop
which does not have a serial port? I purchased a Sabrent usb to serial
adapter t
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