Just started with MySensors and am reading up while playing about.. The OTA programming feature looks great ! But, most of my nodes will be connected over an RS485 bus since that is already in place.

Can you use the OTA feature while using RS485 between gateway en nodes ?

Hi Gohan..

I hooked up my schneider PM9C power monitoring device through modbus to a mysensors node..

Should be doable once you get the initial bus connection running..

Although the familiar RS485 modules on aliexpress etc seem to function just fine when talking to each other, i noticed that it is a pain in the <censored> to get them to talk to a proper device. Especially the direction control screws everything up most of the time..

things cleared up as soon as i started using a RS232 <-> RS485 converter with auto direction control.. Communicating with a single device is one thing, talking to a bus system connecting multiple devices is a whole different ballgame where propper bus termination etc. becomes important.

Biggest problem is that you have to get the hardware for the connection right AND figure out the use of the lib etc.. The other part is having to figure out how your modbus devices present their data..

Search for a good manual for your devices, specifying the various registers to read and write to, including their format etc. It's not that hard, but most devices wont respond at al unlessyou format things exactly right.

So my advice is to split the steps to make sure each part functions on its own before trying to talk end to end.

Use a program like modbuspoll or something and see if you can get the communication going using simple queries to a single HVAC unit using a simple usb converter (i used a little moxa converter). If that works, expand to talking to multiple on the full bus.

Try reading single registers and setting simple things.

if that all works well with the manual queries from modbuspoll or other software, transition to using your mysensors node and libs..

Can you provide some more information about the device types you are using ?

I

The S_WATER sensor type only defines V_FLOW and V_VOLUME to measure water usage.

Please add the existing V_PRESSURE variable (only used for S_BARO) so water pressure measurements are included for the S_WATER type.

Hi Gohan..

I hooked up my schneider PM9C power monitoring device through modbus to a mysensors node..

Should be doable once you get the initial bus connection running..

Although the familiar RS485 modules on aliexpress etc seem to function just fine when talking to each other, i noticed that it is a pain in the <censored> to get them to talk to a proper device. Especially the direction control screws everything up most of the time..

things cleared up as soon as i started using a RS232 <-> RS485 converter with auto direction control.. Communicating with a single device is one thing, talking to a bus system connecting multiple devices is a whole different ballgame where propper bus termination etc. becomes important.

Biggest problem is that you have to get the hardware for the connection right AND figure out the use of the lib etc.. The other part is having to figure out how your modbus devices present their data..

Search for a good manual for your devices, specifying the various registers to read and write to, including their format etc. It's not that hard, but most devices wont respond at al unlessyou format things exactly right.

So my advice is to split the steps to make sure each part functions on its own before trying to talk end to end.

Use a program like modbuspoll or something and see if you can get the communication going using simple queries to a single HVAC unit using a simple usb converter (i used a little moxa converter). If that works, expand to talking to multiple on the full bus.

Try reading single registers and setting simple things.

if that all works well with the manual queries from modbuspoll or other software, transition to using your mysensors node and libs..

Can you provide some more information about the device types you are using ?

I

I implemented this with a schneider PM9C using modbus which works fine

Zigbee is just transport, shouldnt be to hard to translate.. You need the manual to see what data it provides, which i couldnt find online. The model you specified has been of the market for some years.

Tried ir, but no change.. Serial0 was still used while serial1was defined

I amusing an Arduino mega as serial <-> RS485 gateway node..

I first tested using the default softserial solutionfrom the examples,and this works fine..

Then i added :
#define MY_RS485_HWSERIAL Serial2

So i could use serial2 as hardware serial for RS485. Which did not work. There was no activity on the tx of serial 2at all.

After some switching between hard and softserial during testing it worked all of a sudden.. I thought.. Turned out i left the max485 to the softserial pins.

So even when the hwserial is defined, the softserial is still used!?!?

Is this something anybody else noticed as well?

Also keepin mind that those cheap rs485 adapters have a 120ohm load resistor and pull up and pulldown resistors installed for the rs485 bus..

Those should only ve installed on the ends of the data bus.. So remove them from the rest of the adapters if you use more than 2.

No, connecting ground is not mandatory.. In fact, i would not recommend it at all, especialy not on longer bus lengts.. Just use A&B

If you have shielded cables.. Connect the shielding to gnd on 1 side only and leave the other side unconnected..

This will provide shielding but prevent ground loop issues.

Ah that My_Serialdevice setting is something i completely missed..will test that this weekend..

i am fine with the debug going to the usb port.. it's just that i can leave the usb to my pc for programming and debugging while another serial is connected to the raspberry pi running domoticz for the mysensors gateway part.

Looks great !

Have you measured what the minimum load is for the dimmer to function correctly ? I currently use X10 in wall modules but run in to trouble when switching to LED lights. The load is too small.

Old topic but still..

A variable to specify the position of a door would be handy in my opinion. The V_TRIPPED variable of a door sensor just states Closed or Not Closed. But for bigger and mechanical doors like garage doors there is quite a big step between fully open and closed..

The current S_DOOR sensor type for door/windows sensors only has variables to indicate is the door sensor is tripped and to see if it is armed or not.

Please add a variable to indicate the door position (aka, how far a garage door is opened in % of distance)
The V_LEVEL and V_DISTANCE variables are already defined.