pas simple 
30 16 * * *
You can persist entries to file and restore them when node-red starts.
For example, you could write the entries to file using this then on start-up get them back and inject into the Cron node.
That's what is meant by being flexible and dynamic.
But for now, concentrate on getting your functionality correct, then, later figure out how to save and restore after node-red restart.
ok merci 
j'ai trouvé ça : https://notenoughtech.com/home-automation/a-timer-in-nodered/
I can't find the way out
I found something else with eztimer
I can not the function
if(msg.payload.mon ){
msg.payload = ("true");
}
return msg;
|msg.payload.mon|Boolean: true enables the schedule on a Monday, false disables it.|
|msg.payload.tue|Boolean: true enables the schedule on a Tuesday, false disables it.|
|msg.payload.wed|Boolean: true enables the schedule on a Wednesday, false disables it.|
|msg.payload.thu|Boolean: true enables the schedule on a Thursday, false disables it.|
|msg.payload.fri|Boolean: true enables the schedule on a Friday, false disables it.|
|msg.payload.sat|Boolean: true enables the schedule on a Saturday, false disables it.|
|msg.payload.sun|Boolean: true enables the schedule on a Sunday, false disables it.|
