Python plugin: Modbus RTU / ASCII / TCP/IP Topic is solved

[McMelloW]

@McMelloW
No, this is a universal plugin for modbus, it can read 1-4 registers (depending on selected datatype)
It seems like you need a Modbus plugin (written) for your device!

@Domoticx,

Thanks for your update. It was a nice bit of trial and error. Tested the connection with a Win10 modbus scanner to find out what I can expect for data. I will look for other ways to read my SolarEdge

[palmipete]

Hi all,
I have now running since 3 days 3 different Modbus equipments in my house for thermal and energy metering as well as for my heating system.
In general it works quite well (reading).

However, sometimes domoticz, even if it is displaying OK when I check the status, the web interface is blocked.
as soon as I restart domoticz all works again.
This happened 2 times in 3 days.
I tried to put an automatic restart in crontab (hourly) but this did not work yet (I perhaps not so bad in Python, but beginner in Linux).

my main comments to the plugin:
- I would preefer to put an additional parameter in the hardware menu for defining a time step (it is nice to have data every 10seconds, but if I need an energy value every hour this consumed memory for nothing).
- one step further, I am planning to put some kid of check and compare to the last value, and only save data if the change is higher than a limit which is specified in the hardware interface as well
- I do not like these 5 minutes averages in domoticz. For my needs the best would be to save only event based (if change is > threshold) but then keep ALL dataa, also when exporting. I guess this is not the right place to ask this question, but perhaps you have already thought about this since it is typically a problem for periodic measurements (such as modbus) that are in most cases too many values for nothing ...

at the end a question: in the modbus write function, I can switch off my heating system, but it fails later. I think this is due to the hex format of data.
my code is 0 or 1 and I tried: 0x00 for 0 and 0x01 for 1.
but it only cuts the systems, switching on does not work? is this format correct?

Peter

[Domoticx]

Hi palmipete,

Are you using RTU or TCP?

Hi all,
I have now running since 3 days 3 different Modbus equipments in my house for thermal and energy metering as well as for my heating system.
In general it works quite well (reading).

Great!

my main comments to the plugin:
- I would preefer to put an additional parameter in the hardware menu for defining a time step (it is nice to have data every 10seconds, but if I need an energy value every hour this consumed memory for nothing).

There are no more configurable fields available in domoticz....i also wanted timeout and retry setting...but there is no more room...

- one step further, I am planning to put some kid of check and compare to the last value, and only save data if the change is higher than a limit which is specified in the hardware interface as well

Hopefully future versions of domoticz can implement this, based on plugin return data...

- I do not like these 5 minutes averages in domoticz. For my needs the best would be to save only event based (if change is > threshold) but then keep ALL dataa, also when exporting. I guess this is not the right place to ask this question, but perhaps you have already thought about this since it is typically a problem for periodic measurements (such as modbus) that are in most cases too many values for nothing ...

Hopefully future versions of domoticz can implement this...

at the end a question: in the modbus write function, I can switch off my heating system, but it fails later. I think this is due to the hex format of data.
my code is 0 or 1 and I tried: 0x00 for 0 and 0x01 for 1.
but it only cuts the systems, switching on does not work? is this format correct?

The HEX seems ok, are you sure you need to send 0x01 to switch it on?, what does the manual say?

[palmipete]

I use Modbus RTU with a USB converter.
I understood the code so no I could make it work as I wanted (Modbus write).
I also wrote a code as python plugin to make an Event-Logger (check all 10 secs for new values and save to a daily log file).
perhaps somebody is interested in.

[JackWolfskind]

Hi,

I'm currently stuck with the error "Modbus error communicating!, check your settings!" with two different Modbus TCP devices which work fine with different home automation SW.

Anybody got Modbus TCP working with any device at all?
Thanks
Jack

[pablo86]

good morning.
i have the same problem with tcp modbus

2018-02-14 22:19:21.747 (test) MODBUS DEBUG TCP CMD - Method=tcp, Address=192.168.3.5, Port=502, Register=9, Data type=16int
2018-02-14 22:19:21.747 (test) Modbus error communicating!, check your settings!
2018-02-14 22:19:21.747 (test - ModbusDEV-READ) Updating device from 0:'0' to have values 0:'0'.
2018-02-14 22:19:21.748 (test) Modbus error decoding (or recieved no data)!, check your settings!
2018-02-14 22:19:21.748 (test - ModbusDEV-READ) Updating device from 0:'0' to have values 0:'0'.

my hardware is ad4eth Papouch 4-20mA 4 analog input

with software medford work fine

[JackWolfskind]

Actually it seems this plugin only supports "Modbus RTU over TCP" (which is Modbus RTU send over TCP by a serial to LAN converter ) and not the more much common "Modbus TCP protocol", which is very similar but with different structure!
Maybe this helps to better understand:
http://control.com/thread/1305797461

Maybe in the future the plugin can Support both ways?

[Domoticx]

Hi Jack,

I think you are right, so maybe i can make a test plugin with this:
https://pypi.python.org/pypi/pyModbusTCP/

will make a alpha/beta plugin soon to test things out!

[papoo]

will make a alpha/beta plugin soon to test things out!

great

[McMelloW]

will make a alpha/beta plugin soon to test things out!

+1 looking forward to it

[Domoticx]

Hi All,

Here is the TEST APLHA PLUGIN

So now you need 2 modbus dependancies:

- PYMODBUS v1.4.0 or higher
- Install for python 3.x with: sudo pip3 install -U pymodbus
- PYMODBUSTCP v0.1.5 or higher
- Install for python 3.x with: sudo pip3 install -U pymodbusTCP

Option "TCP" is now modbusTCP and other has been renamed to "RTU over TCP"

Please test if the code/plugin works! (i do not have TCP hardware to test it on)

*edit file removed* (now got my own test software )

[papoo]

You can use a modbus esclave simulator
Here one
https://sourceforge.net/projects/modrssim/

[Domoticx]

Thanks for that!

Ps. i see i also got another import error, i will look how to solve (*sigh*....domoticz paths....)

[Domoticx]

Thanks for that!

Ps. i see i also got another import error, i will look how to solve (*sigh*....domoticz paths....)

Fixed the importbug.

Ps. is port 502 default?

Also with the simulator i can use the machines IP right?

[Domoticx]

Yes!! got a Python script working with the windows simulator!! but there is/was a catch hahaha, i have to make the plugin a bit smarter....

Stay tuned!

[Domoticx]

Well tested it with te emulation software, got a working version now!!

I proudly present READ v1.1.0 with true TCP/IP support (grab @ Github) >> https://github.com/DomoticX/domoticz-modbus

Enjoy!, let me show your findings and neat projects!!

Ps. my tests and config:

modbus tcp-ip screen 01 emulator or device.png (23.13 KiB) Viewed 3706 times

modbus tcp-ip screen 02 config.png (153.12 KiB) Viewed 3706 times

modbus tcp-ip screen 03 dash.png (29.26 KiB) Viewed 3706 times

[papoo]

Great

[McMelloW]

Looks great !!
What is the length of the register you can read? For the SolarEdge over port 502, you have to read 0 - 122 positions.

[freijn]

looks good, curious on results !

[McMelloW]

Installing the READ plugin hangs domoticz. After restarting Domoticz, no screen visible and no connection via the browser is possible. SSH via Putty remains active. Removing the plugin from the Plugin directory and Domoticz restart solved the problem.

It is sadly, because it looked promising