Modbus poll openhabian

Can someone tell me what is trigger for poll mechanism in linux (openhabian on rbpi) Modbus service ?
What i see (the same setup files) on windows - poll parameter in modbus cfg file actually make Modbus LED ackt on slave unit blink from time to time, on rbpi blinking occur only when i made change of value on dimmer.
So it looks like poll parameter is omitted ? or it’s based on RTC ?