User Manual

www.N2KB.nl Page 3
3 I NTRODUCTION
The NANO is designed to be used in a fully integrated system. Remote devices can read the status and
parameters of the NANO by a digital bus system. The technology used is MODBUS. This is a very well-
established bus technology that uses RS-485 as the underlaying physical layer. Please read the NANO
User Manual before using the device. This manual only manages the data bus usage.
4 C ONNECTING THE DATA BUS
RS-485 is a 3-wire bus. Two wires for the communication data and one wire for the ground connection.
Be aware that this ground wire must always be connected and physically kept together with the two
data signal lines. Not connecting this wire can lead to communication faults and even damaged devices
due to EFT or Surge events or Voltage level differences between different floating ground potentials.
Make sure the A and B date lines are not reversed. Although nothing can be damaged, the
communication will not work that way.
It is strongly recommended to use a twisted pair cable to reduce the risk of communication failures
due to Electro Magnetic Interference (EMI). Twisting all four lines together instead of twisting in pairs
of 2 is also a good solution.
5 C ONNECTION SETTING
The MODBUS type is RTU and the settings of the communication are 8N1 baudrate 9600.
This means:
 Baudrate 9600 bps
 1 start bit
 8 data bits
 Geen pariteits bit
 1 stop bit