What is RS485 serial communication? How to use RS-485 MODBUS to design Arduino point-point network. 

Thanks for the compliment.

Many thanks my friend, happy learning.

Happy to hear that Teddy, Happy learning.

Thanks Pawel for your comment, The RX and TX LEDs are blinks while transmitting the data due to the data transfer from the serial monitor to the MCU only and nothing to do with MODBUS modules.

Sorry for the late reply, You are correct, I can see what do you mean. To put it simply: The master node need to receive an input from the slave to enter the if(serial.available) condition and at the end set the digitalWrite(RS_DE_RE, "LOW");. Then the master can receive data from the slave. That's make sense, will update this issue in the future. Thanks for your input.

Thanks. Happy learning

Thanks to you too. Happy learning.

Many thanks my friend.

Thanks, Happy learning.

Thanks a lot, happy learning.

Thanks, happy learning.

Thank you, happy learning.

You can directly use a wireless modules instead, there are wireless modules that support serial UART interface. You may check these videos: ru-vid.com/video/%D0%B2%D0%B8%D0%B4%D0%B5%D0%BE-W2Ha3vBpxSM.html&ab_channel=ChallengerTech. ru-vid.com/video/%D0%B2%D0%B8%D0%B4%D0%B5%D0%BE-h883lBQIhuo.html&ab_channel=ChallengerTech. ru-vid.com/video/%D0%B2%D0%B8%D0%B4%D0%B5%D0%BE-yz9r2c4diLA.html&ab_channel=ChallengerTech. ru-vid.com/video/%D0%B2%D0%B8%D0%B4%D0%B5%D0%BE-kgkSilELi-w.html&ab_channel=ChallengerTech.

Hello Haziq, to implement the scenario that you described it you need data addressing scheme to request and receive the specific data, you may check these videos: ru-vid.com/video/%D0%B2%D0%B8%D0%B4%D0%B5%D0%BE-diDnelKFqg0.html&ab_channel=ChallengerTech.ru-vid.com/video/%D0%B2%D0%B8%D0%B4%D0%B5%D0%BE-RyiIGNZ__jI.html&ab_channel=ChallengerTech. ru-vid.com/video/%D0%B2%D0%B8%D0%B4%D0%B5%D0%BE-HUCiRF5Ceh0.html&ab_channel=ChallengerTech. ru-vid.com/video/%D0%B2%D0%B8%D0%B4%D0%B5%D0%BE-03ZZmRFTGYU.html&ab_channel=ChallengerTech.

Does pzem 004t have memory to store the total energy consumption even when turned off.

Thanks my friend

In this tutorial I am using MAX485 module and Arduino UNO. They are available in abundant online.

Sorry I am not using Mac.

Sorry, I do not keep/upload the sketches. You may need to follow the video steps, I explain everything in details.

Hello, yes sure can. Will try to make another tutorial about the RS485 with the raspberry pi.

I will try my best to implement that.

Hello Ricardo, I am working in developing multi-hop example with more than 2 modules, gonna release it soon.

Sorry for the late reply, Well, the RS485 is a differential signal so no common ground is required. However, Connecting the GND wire between the source and receiver might be useful to limit the common mode voltage that can be impressed on the receiver inputs.

a work around by opening the master in IDE 1.8 and the slave in IDE 2.0

Hello@@keithbrown162 , well, you may try to open 2 arduino IDE instances at the same time, then you set different COMs following the arduino boards. This is what I usually do.

This module is providing the physical MODBUS layer, on the software part you may need to develop your own protocol to match the target.

So in the end , there is no master or slave actually . The master could just use the same code which the slave use.

Hello@@MrWangsan That's correct.

Hello Jobson, Yes, You are right, Need to join the A and B wires but in a multi-drop connection manner. I am working in developing multi-hop example with more than 2 modules, gonna release it soon.

BTW Jobson since you gonna interconnect more that 2 modules, you gonna need an addressing scheme as in: ru-vid.com/video/%D0%B2%D0%B8%D0%B4%D0%B5%D0%BE-03ZZmRFTGYU.html&ab_channel=ChallengerTech. ru-vid.com/video/%D0%B2%D0%B8%D0%B4%D0%B5%D0%BE-HUCiRF5Ceh0.html&ab_channel=ChallengerTech. ru-vid.com/video/%D0%B2%D0%B8%D0%B4%D0%B5%D0%BE-RyiIGNZ__jI.html&ab_channel=ChallengerTech. ru-vid.com/video/%D0%B2%D0%B8%D0%B4%D0%B5%D0%BE-diDnelKFqg0.html&ab_channel=ChallengerTech.

Sorry for the late reply, although the digital sensor support RS485 as a communication, there might be a specific protocol/commands sequence to talk to it. Might need to check the sensor manual/datasheet first. Will try to work on the MODBUS RTU examples in the future.

Sorry for the late reply, Well, No specific RS485 library in my head. However, you can do your own one, not that hard though. Here is a tutorial show you how: ru-vid.com/video/%D0%B2%D0%B8%D0%B4%D0%B5%D0%BE-AXzksa8JDnE.html

Hello gokhankunt3884, Well, you need to study the HMI RS commands then use arduino to send them to the HMI.

Thanks

Not needed as the MAX485 supports TTL directly.

TX Rx is for modbus TCP ......not for modbus RTU (rs 485)

I don't think you can do so, you gonna need a repeater to maintain the signal at each 1km.

You may need to double check the terminal resistor.

Hello ankitkailashi9777, These tutorials will help you to receive data from any device: ru-vid.com/video/%D0%B2%D0%B8%D0%B4%D0%B5%D0%BE-9CwwZ-SMMoA.html ru-vid.com/video/%D0%B2%D0%B8%D0%B4%D0%B5%D0%BE-k5Jgrq3NzB0.html ru-vid.com/video/%D0%B2%D0%B8%D0%B4%D0%B5%D0%BE--P71Xbzs57c.html

Sure can kourivi, you may need to study the HMI commands so you can send them through the serial.

@@AliChallenger yup I did ;)

So sorry for that, but, for the time been you can follow the tutorial directly.

@@AliChallenger oh the tutorial itself was great :P works like a charm

Thanks for your comment.

Commonly talking, VCC = [3.3 - 6]V A, B = [-9 - 14]V However, it is better to consult the chip datasheet to conform the ranges.