@mfalkvidd Thanks for your time and your warning....
My problem with mysensors is that the only way I know to collect the data received by the GW through mysensors is domoticz, and domoticz reports data to me every 5 minutes. I like to monitor the data through internet, together with meteo, home temperatures and so on.
But a 5 min period is not frequent enough to show me the progressive change in the water level when the pump is working (the average duration of a period of powered on pump is most often a handle of minutes) : to achieve this, my node samples and sends data to GW approx every 5 seconds and it is frustrating to find data in domoticz only every five minutes.
To cope with this issue, I have presently a second -independant- pair of arduino linked by nr24 protocole : one of them collect the data and send them every 5 secondes to the 2nd arduino which starts electromechanical timers cumulating the working time of the pumps with sufficient reliability and accuracy. This cumulated time, cross checked with meteo data and water level, is useful to me to verify that the pumps are working normally. The problem is that I do not know a way to access these info via internet.
So my today situation is that I have, working in parallel, the mysensors system, opened on internet but poorly reactive, and the nr24 system, accurate enough, but that I can only read when I am at home.... Fortunately, presently, these two systems work in parallel apparently without interfering negatively....
My dream would be to unify the two systems....

Thank you for these info. I will have a look on tutorials on scripts and lua in Domoticz. Not so obvious at first glance ! I will need time....
Thanks again.

Are 'mysensors' and 'RF24' libraries fully compatible with the nrf24l01, the nrf24l01+ and the nrf24l01 PA LNA ?

@Sasquatch
I often read that both types of nrf24l01 were software compatible. However a problem is possible.... Since my first node is working perfectly with a nrf24l01 PA+LA it should not be the origin of the problem. But again everything is possible.....
Another idea is that because my first node has been working successfully for several years, the nrf library it is using is old and might have been updated, and an issue might come from a non compatibility between old and new version. But I am not ready to reload an updated sketch at risk of generating unexpected trouble on my working node !!!!
I go on investigating....
One thing I will try to change is the special chip feeding the nrf24l01 from the UNO power supply (and carrying comm signals). I will try to do it.

@nagelc I have 'define my_debug' in the sketch. I get this (sample) in the log : Do you have any idea ?
....
16 MCO:BGN:INIT NODE,CP=RNNNA---,FQ=16,REL=255,VER=2.3.2
26 TSM:INIT
28 TSF:WUR:MS=0
34 TSM:INIT:TSP OK
36 TSM:FPAR
38 ?TSF:MSG:SEND,255-255-255-255,s=255,c=3,t=7,pt=0,l=0,sg=0,ft=0,st=OK:
2048 !TSM:FPAR:NO REPLY
2050 TSM:FPAR
2052 ?TSF:MSG:SEND,255-255-255-255,s=255,c=3,t=7,pt=0,l=0,sg=0,ft=0,st=OK:
4060 !TSM:FPAR:NO REPLY
4062 TSM:FPAR
4064 ?TSF:MSG:SEND,255-255-255-255,s=255,c=3,t=7,pt=0,l=0,sg=0,ft=0,st=OK:
6072 !TSM:FPAR:NO REPLY
6074 TSM:FPAR
6076 ?TSF:MSG:SEND,255-255-255-255,s=255,c=3,t=7,pt=0,l=0,sg=0,ft=0,st=OK:
8084 !TSM:FPAR:FAIL
8085 TSM:FAIL:CNT=1
8087 TSM:FAIL:DIS
8089 TSF:TDI:TSL
18091 TSM:FAIL:RE-INIT
18093 TSM:INIT
....
And parser gives me (sample) :
34 TSM:INIT:TSP OK Transition to Init state:TSP OK
36 TSM:FPAR Transition to Find Parent state
38 ?TSF:MSG:SEND,255-255-255-255,s=255,c=3,t=7,pt=0,l=0,sg=0,ft=0,st=OK: Sent Message without radio ACK
Sender: 255
Last Node: 255
Next Node: 255
Destination: 255
Sensor Id: 255
Command: INTERNAL
Message Type:I_FIND_PARENT_REQUEST
Payload Type: P_STRING
Payload Length: 0
Signing: 0
Failed uplink counter: 0
Status: OK (OK=success, NACK=no radio ACK received)
Payload:
2048 !TSM:FPAR:NO REPLY No potential parents replied to find parent request

Thanks for your answer.
I do not see anything new in the domoticz log when I reset the Uno. Just in case, I have already changed the NRF24L01+PA&LA and added a 33uF capacity between its power lines : no change. The first node is still working perfectly, so that I assume that the reception part on the gateway and controller is OK.
I go on investigating.....

Hello, I am a beginner in domotic, and I have a very basic question : in a mysensors network controlled by domoticz, is it possible to use several nodes with one gateway ? I use presently -working like a charm- a network with one Uno node, with nrf24L01, with 6 children, to monitor the water level in a well and several pumps start/stop. I would like to add a 2nd node (another Uno with nrf24) in another place, reporting to the same gateway and domoticz controller, with one child sensor, but I do not manage to do it. The 2nd Uno does not appear in the list of materials / devices of mysensors box in Domoticz. Is there a special procedure I do not know to get this new node recognized in Domoticz ? What could I be missing ?
My controller and my present gateway are hosted on a raspberrypi 3.
Thanks very much in advance.

Thank you for these info. I will have a look on tutorials on scripts and lua in Domoticz. Not so obvious at first glance ! I will need time....
Thanks again.

Hello
Thank you for this description of your installations. There are many similarities with mine. Except -as I understand- that your risk might be an empty tank, while I fear an overflow of mine in case of strong rain and pump failure, resulting in flooding my cellar.... But basically I could find a solution similar to yours to show in a Domoticz graph (date and time on horizontal axis), when a pump is turned on, by drawing vertical segments every 5 min of domoticz, with a height showing the duration - cumulated by the node- of pump working since the moment it has been turned on. And this duration would be reset when the pump is turned off.
I think I can do that without using interrupts on Arduino and dummy variables in Domoticz that I do not really master (I have never experienced them).
One of the difficulties I expect when doing that is to manage the risk that Domoticz records a 5 min sample a few minutes (i.e. 2 min) before the pump is turned off : in that case, the duration working time displayed would be underestimated. I am confident that I can find a turnaround to cope with this difficulty, maybe by a delay (5min ?) of the reset by the node of the cumulated time after pump turn off.
Anyway, it will be a funny challenge...

@BearWithBeard Thanks for your answer. My feeling is that you describe a perfect solution (with database + Grafana etc...). The possibility of linking influxdb and domoticz looks very promising.
The issue is that I have presently no competence in these tools, and my knowledge of Domoticz is limited to the basis. I am therefore reluctant in jumping directly in such an adventure
However I will go on thinking to this option, at least maybe in a first step for brain training.....
Thanks again.

@mfalkvidd Thanks for your answer.
I understand the possible advantages of a controller change.
But I am 75 years old, and I tend to be prudent in front of drastic changes in my installation. I would not like to migrate from a system unperfect but basically working to a system theoretically better but that I could not master.
I like your idea of calculating at node level cumulated times of pump working, , and transferring them to Domoticz, instead of the amperage drawn by my pumps that I transfer today (at the beginning I expected to forecast early some pumps malfunctions by checking evolution with time of the absorbed power, but I do no more think today that it is realistic). I will modify the sketches in this way during the next days (or maybe weeks). I will keep you informed when it is working.
Could you kindly developp a little further your idea of skipping the controller and logging data to a file, so that I can evaluate if this is in my range of competence ?
Many thanks again.

@mfalkvidd Thanks for your time and your warning....
My problem with mysensors is that the only way I know to collect the data received by the GW through mysensors is domoticz, and domoticz reports data to me every 5 minutes. I like to monitor the data through internet, together with meteo, home temperatures and so on.
But a 5 min period is not frequent enough to show me the progressive change in the water level when the pump is working (the average duration of a period of powered on pump is most often a handle of minutes) : to achieve this, my node samples and sends data to GW approx every 5 seconds and it is frustrating to find data in domoticz only every five minutes.
To cope with this issue, I have presently a second -independant- pair of arduino linked by nr24 protocole : one of them collect the data and send them every 5 secondes to the 2nd arduino which starts electromechanical timers cumulating the working time of the pumps with sufficient reliability and accuracy. This cumulated time, cross checked with meteo data and water level, is useful to me to verify that the pumps are working normally. The problem is that I do not know a way to access these info via internet.
So my today situation is that I have, working in parallel, the mysensors system, opened on internet but poorly reactive, and the nr24 system, accurate enough, but that I can only read when I am at home.... Fortunately, presently, these two systems work in parallel apparently without interfering negatively....
My dream would be to unify the two systems....