I already have connected RTU with flow meter . I wanted to know the parameter from flowmeter with modbus protocol. RTU power is 7.2 V , should I need external power supply ?
As per my understanding, communication established between RTU and flow meter. Now you need to configure the flow meter parameters in the RTU.
Refer the respective flow meter technical manual or serial communication document, you will find the all modbus related data like address, configuration parameters and respective mapping details.
if you don’t find the mapping details, contact O.E.M for the details.
In general, you don’t need any external power supply for modbus communication. in case if you use any converters in between then you may need it, depends on your design.
I am attaching a sample documents for reference.
Flow Meter Modbus RTU Interface.pdf (1.0 MB)
Thank you Mr Bharadwaj