I on project to get the value through arduino rs485 MODBUS protocol and having some problem with connecting the wire, serial communication coding . Can i get some advice with this
Can you please draw your circuit with pen(cil) and paper so we can see your circuit?
The Fritzy picture is of little use.
Please label components, pinouts and power supply.
Please post your code.
RS485 is a balanced transmission system using 2 wires for the signal plus a ground. The Arduino products do not directly support RS485. In order to connect an RS485 device to any Arduino you need a converter / interface to convert RS485 to TTL level serial. I leave you to search for such a thing.
Thankfully @leeseunghyuk is using them, but needs a better schematic to see if it is connected correctly.
Are you sure Tom? Is that what those things are to the right of the image? Like you say, decent schematic needed.
Yes, I have two of them on my bench now ready to go...
This your thread?
The wiring should be as per Pylon’s instruction in the other thread. You have many unwanted/unnecessary connections. Adapted from that thread:
On the upper adapter connect RE/DE directly to GND and only RO to pin 3. DI is not connected.
On the lower adapter connect RE/DE directly to 5V and only DI to pin 4. RO is not connected.
If the boards survived your short circuit you may be successful given you use a SoftwareSerial on pins 3 and 4.