I am using 20 sensor nodes, each has mpu9250 i2c, Arduino atmega328 MCU 8MHz and max485 chip in it, each slave has a unique id program.
I have Arduino due as Modbus master with max485 chip, I hope to use Arduino Modbus library RS485 RTU,
assume slave is continually reading data and updating local variable with imu data 12bytes, and ready to send over the bus.
and master is polling data from each slave node.
all sensor are connected the same bus, 1.5ft from the sensor node to sensor node away each (cat 5 cables), the reason to choose Modbus is having higher data rates compared to CAN bus or I2C,
I have a doubtable point,
how long it will take to respond to master with data?
how to calculate request/response time or the time to gather data from all sensors by the master?
in other words how many samples per second achievable?