I cannot regularly receive the value from a measuring device

Hello ,

I cannot regularly receive the value from a measuring device, on the other hand I receive the timestamp value on a regular .
I need your help

Add debug nodes to the outputs of the other function node and the modbus node and see where it is getting lost. If you give the debug nodes names it is easier to identify them in the debug pane.

My problem in node Mobus
I make repeat interval 3 seconds work fine but if I make 3 minutes not working

Is there any output from the modbus node at all when it fails?
Does the status shown against the node show anything?

Start node-red in a terminal and leave the window open until the modbus node fails. Then copy/paste the output here (from the beginning). To paste it here use the </> button at the top of the forum text window and paste it in.
Also tell us what OS you are running node-red on.

It is worked after using interval length after node modbus

Adding the Interval Length node cannot have made a difference to whether the modbus node worked or not.

for me if I make interval length before modbus it is not working
also if i make interval in timestamp ( 3 minutes) is not working
but if i make interval in timestamp ( seconds) is working fine
I not understand why
but with the solution (interval length after modbus ) it is working fine

Ah, you mean you have found a workaround rather than actually finding the cause of the problem.

yes exactly

OK, my experience when designing a system in that way is that at some point the problem will rear its head again and bite you in the backside.