https://github.com/ho-ro/openmetra
Remote control for multimeter Gossen METRAHit 29S via BD232 serial interface
https://github.com/ho-ro/openmetra
gossen metrahit multimeter python
Last synced: 9 months ago
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Remote control for multimeter Gossen METRAHit 29S via BD232 serial interface
- Host: GitHub
- URL: https://github.com/ho-ro/openmetra
- Owner: Ho-Ro
- License: gpl-3.0
- Created: 2022-02-02T19:06:24.000Z (over 4 years ago)
- Default Branch: main
- Last Pushed: 2022-10-17T20:26:51.000Z (over 3 years ago)
- Last Synced: 2025-03-17T04:07:49.543Z (over 1 year ago)
- Topics: gossen, metrahit, multimeter, python
- Language: Python
- Homepage:
- Size: 182 KB
- Stars: 0
- Watchers: 1
- Forks: 0
- Open Issues: 0
-
Metadata Files:
- Readme: README.md
- License: LICENSE
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README
# OpenMetra
Receives data from a multimeter Gossen METRAHit 29S via BD232 serial interface.
Tested with FTDI and similar RS232 USB serial interfaces to "/dev/ttyUSB0" (linux).
Should also work for Windows with e.g. serial_device="COM8".
Activate the transmission on the instrument with: 'SEt v SEnd <-/ OFF v on <-/',
or at switch-on by depressing **DATA/CLEAR** and **ON** button together.
Rate of data beeing sent can be set in the meter's menu with the item 'rAtE'.
## Hardware
Get [info and documents](https://www.gossenmetrawatt.com/english/produkte/metrahit29s.htm)
from [gossenmetrawatt.com](https://www.gossenmetrawatt.com/).
## Software
Access to the multimeter and decoding of the received data is done in the OpenMetra class.
Just add the directory `openmetra` to your project and you're done.
Switch the meter to transmit mode (press **DATA/CLEAR** and **ON** together) and retrieve the data with this simple program:
```python
#!/usr/bin/python
import sys
from openmetra import OpenMetra
with OpenMetra() as mh: # open connection to '/dev/ttyUSB0', the serial path can be an optional parameter
if mh is None: # could not connect
print( 'connect error', file=sys.stderr)
sys.exit()
while True: # run forever, stop with ^C
try:
print( mh.get_measurement() ) # print numeric value
except KeyboardInterrupt: # ^C pressed, stop measurement
print()
break # exit
```
The provided program [Metra](https://github.com/Ho-Ro/OpenMetra/blob/main/Metra)
allows to customize the received date with some options:
````
usage: Metra [-h] [-c] [-d SERIAL_DEVICE] [-f] [-g] [-n NUMBER] [-o] [-O] [-r RATE]
[-s SECONDS] [-t] [-T TIMEOUT] [-u] [-U] [-v] [-V]
Get data from Gossen METRAHit 29S
optional arguments:
-h, --help show this help message and exit
-c, --csv create csv (together with -t and/or -u)
-d SERIAL_DEVICE, --device SERIAL_DEVICE
device path of serial interface, default is "/dev/ttyUSB0"
-f, --format_values print formatted values (instead of as shown on meter)
-g, --german use comma as decimal separator, semicolon as field separator
-n NUMBER, --number NUMBER
get NUMBER measurement values
-o, --on-off switch meter on, select send mode and rate and switch off after
measurement
-O, --overload print OL values as "None" instead of skipping
-r RATE, --rate RATE select index for measurement rate: 0:50ms, 1:0.1s, 2:0.2s, 3:0.5s,
4:1s, 5:2s, 6:5s, 7:10s, 8:20s, 9:30s, 10:1min, 11:2min, 12:5min,
13:10min, default: 4 (1s)
-s SECONDS, --seconds SECONDS
measure for a duration of SECONDS
-t, --timestamp print timestamp for each value
-T TIMEOUT, --timeout TIMEOUT
set timeout for serial port
-u, --unit print unit of measured value
-U, --unit_long print unit of measured value with explanation, e.g. AC, DC, etc
-v, --version show openmetra version
-V increase verbosity
````
The program [MetraPlot](https://github.com/Ho-Ro/OpenMetra/blob/main/MetraPlot)
displays the measured data nicely:
````
usage: MetraPlot [-h] [-t TITLE] [-f FIRST_SAMPLE] [-l LAST_SAMPLE] [-V] [infile]
Plot data - e.g. received from Gossen METRAHit 29S via program 'Metra'
positional arguments:
infile read measurement data from optional infile, use stdin otherwise
optional arguments:
-h, --help show this help message and exit
-t TITLE, --title TITLE
set the title of the plot, default is 'MetraPlot'
-f FIRST_SAMPLE, --first_sample FIRST_SAMPLE
first sample to display
-l LAST_SAMPLE, --last_sample LAST_SAMPLE
last sample to display
-V increase verbosity
````
The program [MetraSwitch](https://github.com/Ho-Ro/OpenMetra/blob/main/MetraSwitch)
switches the instrument on and selects send mode or selects the measurement function or switches the intrument off:
````
usage: MetraSwitch [-h] [-d DEVICE] [--off | --function FUNCTION | --rate RATE | --set_rtc]
[-v] [-V]
Gossen METRAHit 29S: switch off or select function or select data rate or set RTC time and
date. Without specifying an action the meter is just switched on.
optional arguments:
-h, --help show this help message and exit
-d DEVICE, --device DEVICE
device path of serial interface, default is "/dev/ttyUSB0"
--off switch the device off
--function FUNCTION select measurement function: 1:V_DC, 2:V_ACDC, 3:V_AC, 4:mA_DC,
5:mA_ACDC, 6:A_DC, 7:A_ACDC, 8:Ohm, 9:F, 10:dB, 11:Hz_Uacdc,
12:Hz_Uac, 17:Ohm buzzer, 18:Temp, 22:pulseW, 23TRMS_mains,
24:Counter, 25:Events_Uacdc, 26:Events_Uac
--rate RATE select index of measurement rate: 0:50ms, 1:0.1s, 2:0.2s, 3:0.5s,
4:1s, 5:2s, 6:5s, 7:10s, 8:20s, 9:30s, 10:1min, 11:2min, 12:5min,
13:10min
--set_rtc set meter RTC time and date from local time
-v, --version show openmetra version
-V increase verbosity
````
### Building and Installing a Debian Package
The provided [Makefile](https://github.com/Ho-Ro/OpenMetra/blob/main/Makefile) allows to build a Debian package,
just type `make`. `make distclean` removes all created data to prepare for a new clean build.
You need to install python3-stdeb, the Python to Debian source package conversion plugins for distutils.
After success the package is available as `openmetra_*_all.deb`.
You can do a clean install (as root) with `dpkg -i openmetra_*_all.deb`, the python module `openmetra` is put into
the python3 library path, the scripts `Metra*` are copied into `/usr/bin`. `dpkg -P openhantek` does a clean uninstall.
It is also possible to build an (experimental) rpm package with `make rpm` as `openmetra-*.noarch.rpm`.
## Protocol Definition:
The instrument sends the data blocks with 9600 Bd, 8 bits + Start + Stop bit (only lower 6 bits are used).
### Fast Mode
TM1a) Measured data with fast rate (rate 50 ms, V_DC, A_DC only)
````
-----------------------------------------------
|Byte| Output unit Bit0..Bit3 |Bit5|Bit4|
|----|------------------------------|----|----|
| 1 | Measuring range, sign | 0 | 1 |
| 2 | Units | 1 | 1 |
| 3 | Tens | 1 | 1 |
| 4 | Hundreds | 1 | 1 |
| 5 | Thousands | 1 | 1 |
| 6 | TenThousands | 1 | 1 |
-----------------------------------------------
````
TM1b) Instruments setting with fast rate (sent at lower rate of ~ 500 ms)
````
-----------------------------------------------
|Byte| Output unit Bit0..Bit3 |Bit5|Bit4|
|----|------------------------------|----|----|
| 1 | Device code, 1110 is 29s | 0 | 0 |
| 2 | Curr. type, meas. variable 1 | 1 | 1 |
| 3 | Special character 1 | 1 | 1 |
| 4 | Special character 2 | 1 | 1 |
| 5 | Measuring range, sign 1 | 1 | 1 |
-----------------------------------------------
````
### Slow Mode
TM2) Ranges: V AC, V AC+DC, I AC+DC, Ohm, Ohm with buzzer, F, Hz , Temp., dB,
V-diode, V-diode with buzzer, Events, Counter, Mains analysis and Power.
Also V DC, A DC and functions when send interval >50 ms.
````
-----------------------------------------------
|Byte| Output unit Bit0..Bit3 |Bit5|Bit4|
|----|------------------------------|----|----|
| 1 | Device code, 1110 is 29s | 0 | 0 |
| 2 | Curr. type, meas. variable 1 | 1 | 1 |
| 3 | Special character 1 | 1 | 1 |
| 4 | Special character 2 | 1 | 1 |
| 5 | Measuring range, sign | 1 | 1 |
| 6 | Units | 1 | 1 |
| 7 | Tens | 1 | 1 |
| 8 | Hundreds | 1 | 1 |
| 9 | Thousands | 1 | 1 |
| 10 | TenThousands | 1 | 1 |
| 11 | HundredThousands | 1 | 1 |
| 12 | Curr. type, meas. variable 2 | 1 | 1 |
| 13 | Send interval | 1 | 1 |
-----------------------------------------------
````
29S: In case of power measurement there are sent 3 of these blocks
with delay 200 ms in order power - W, voltage - V, current - A.
### Function Encoding
The meter's function is transmitted in `Current type measuring variable 1` (fast mode)
or `Current type measuring variable 1` and `Current type measuring variable 2` for slow mode.
Thes values were verified with my METRAHit 29s:
TM3b) Measurement function encoding (also TF)
````
-------------------------------------------------
| Function | Variable2 | Variable1 | Index |
|-----------+-----------+-----------+-----------|
| - | 0000 | 0000 | 0 |
| V DC | 0000 | 0001 | 1 |
| V ACDC | 0000 | 0010 | 2 |
| V AC | 0000 | 0011 | 3 |
| mA DC | 0000 | 0100 | 4 |
| mA ACDC | 0000 | 0101 | 5 |
| A DC | 0000 | 0110 | 6 |
| A ACDC | 0000 | 0111 | 7 |
|-----------+-----------+-----------+-----------|
| kOhm | 0000 | 1000 | 8 |
| Farad | 0000 | 1001 | 9 |
| dBV | 0000 | 1010 | 10 |
| Hz UACDC | 0000 | 1011 | 11 |
| Hz UAC | 0000 | 1100 | 12 |
| W (mA) | 0000 | 1101 | 13 |
| W (A) | 0000 | 1110 | 14 |
| Diode | 0000 | 1111 | 15 |
|-----------+-----------+-----------+-----------|
| Dio buzz | 0001 | 0000 | 16 |
| kOhm buzz | 0001 | 0001 | 17 |
| Temp | 0001 | 0010 | 18 |
| - | 0001 | 0011 | 19 |
| - | 0001 | 0100 | 20 |
| - | 0001 | 0101 | 21 |
| - | 0001 | 0110 | 22 |
| - | 0001 | 0111 | 23 |
|-----------+-----------+-----------+-----------|
| - | 0001 | 1000 | 24 |
| - | 0001 | 1001 | 25 |
| - | 0001 | 1010 | 26 |
| mA (W) | 0001 | 1011 | 27 |
| A (W) | 0001 | 1100 | 28 |
| V (W) | 0001 | 1101 | 29 |
| V DC | 0001 | 1110 | 30 |
| V DC | 0001 | 1111 | 31 |
-------------------------------------------------
````
- See also:
https://www.mikrocontroller.net/attachment/22868/22SM-29S_Interface_Protocol1.pdf
and
https://github.com/sigrokproject/libsigrok/blob/master/src/hardware/gmc-mh-1x-2x/protocol.c