I'm trying to get temperature values from L201 Optical fiber sensor which support RS-485 serial Communication. There is a RS-485 link attached at sensor as shown in the pic consisted with GND/Tx-/Tx+/Rx-/Rx+. Trying to get data from sensor to arduino with MODBUS protocol. Not sure the connection cause Arduino RS-485 Module only have VCC/A/B/GND slot to connect just made Tx-/Tx+ wire together and connected to A. Not sure this is right and don't know how to code even i have this sensor's MODBUS resigter table. Can I get some advice for this project?
This usually means you have the rather seldom bi-directional RS-485 version.
Bad idea unfortunately as this produces a short circuit for the RS-485 driver in the sensor. If it's protected against that you may be lucky otherwise it may be fried.
If you have a manual why didn't you post a link to it?
Then it means i have to rather pick Rx+/Rx- or Tx+/Tx- for data transfer to prevent the short circuit.
Homepage limit new member to attach any file unfortunately. Register table tells me that this sensor uses 0x01, 0x03, 0x04 Function code etc.
It means you need such a RS-485 board for each Rx+/Rx- and Tx+/Tx- where you connect the - pin to A and the + pin to B. On the board connected to the Tx pins you connect DE/RE to GND and RO to the RX of the Arduino and the other board you connect DE/RE to 5V and DI to Tx of the Arduino.
In case i have connected all well. Is there any help for the coding for arduino? i can send you the MODBUS register table by email.
Hmm, this wiring is still wrong. Did you actually read my previous answers? You must have two of these RS-485 adapters.
i have connected the wires as this figure and cant figure it out how to get the signal through the code
That doesn't implement what I proposed. It even produces another short circuit.
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.
The connection to pin 6/7 are not used.
If the boards survived your short circuit you may be successful given you use a SoftwareSerial on pins 3 and 4. As we haven't seen any code we cannot check that.
Topic closed as a duplicate exists
Please do NOT cross post / duplicate as it wastes peoples time and efforts to have more than one post for a single topic.
Continued cross posting could result in a time out from the forum.
Could you also take a few moments to Learn How To Use The Forum.
Other general help and troubleshooting advice can be found here.
It will help you get the best out of the forum in the future.