Questions tagged [rs485]
EIA RS-485 is a serial communication standard using differential signaling.
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Difference between Echelon TPT/XF and RS485 transceivers
We are going to connect to a LonWorks network and all devices connected to network have TP/XF-78 transceiver. Can anyone describe the difference between the two?
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Powering a device from the RS485 lines
I have found multiple RS232 to RS485 converter dongles (from different brands, models, and makes) that do not need external power to operate.
Connect the RS232 DB9 on one side, and three wires for the ...
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How to isolate RS485 (A and B) from existing transceiver? Check attached circuit diagram, is it correct?
I have a controller with an RS485 transceiver, specifically the IS8489EIBZ-T, which is not isolated. I want to connect a BMS system to the output of this transceiver. After some research, I found a ...
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TTL to RS485 converter problems
I have designed a custom PCB that incorporates a circuit for an RS485 to TTL converter. Previously, I successfully used a module (https://protosupplies.com/product/scm-ttl-to-rs-485-interface-module/) ...
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rs485/modbus issue
I am trying to enable modbus RTU communication between 2 inverters.
Both are set up with unique IDs, 9600Hz, 1 stop bit, No parity bit.
I can communicate with 1 at a time, as shown below in the ...
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USB and RS485 on same lines for ESP32-S3
For an ESP32-S3 based PCB that I am developing, I would like to be able to share 1 connector for two different communication protocols.
USB connection directly to IO19 and IO20 of the ESP32-S3-wroom1
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ATTINY85-20SUR and serial communication
I am trying to use this chip ATtiny85 for serial communication. So my question is, would you recommend using it for serial communication, such as storing names, IDs, data, and last operations? Should ...
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Can you connect an RS-485 bus as a loop? (no terminators, cable ends joined)
I'm looking at using RS-485 to connect a bunch of sensors across a lengthy distance (approx 500 metres) however the location of the sensors means it would be suitable for connection as a loop.
By loop ...
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UART communications using CAN bus differential signalling
I need to interface with a device that talks UART, but with CAN bus signalling. Here's a picture where a tester (which I want to replicate) talked to that device:
While RS485 seems similar, the ...
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Help understanding RS485 circuit
Could someone help me understand this circuit? Like what is the purpose of the logic inverter, is it for switching direction automatically? And if so, how is it working?
For example on the TX1 line - ...
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RS485 to CAN converter
I want to design where a RS485 Device Sensor reads inputs and the information it reads and sends is converted to CAN (Arduino UNO R4 Minima with CAN built in, or ESP32 with CAN built in)
Is this ...
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Replacing MAX485ESA IC into a RS485 module but not working
I have been struggling a lot with a MAX485ESA IC I bought from aliexpress. What I want to do is replace the component from a rs485 module. For some reason they don´t work and I was wondering if anyone ...
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How to find out if RS485 interface has termination
We have a battery with built-in BMS and I am preparing a PCB that is supposed to talk to it. I need to decide whether I put 120 ohm standard end termination or 60 Ohm for 20cm short "bus".
...
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Noise during RS-485 operation
I have a switching step-down power supply SCM1301A, from which the entire circuit is powered, namely the microcontroller, op-amp, RS-485. I digitize the signal coming from the microwave module, having ...
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Why are there two wires connected to each terminal of the RS485 port in energy meters
I want to connect the energy meters of our clients to a gateway so that the gateway can communicate with the meters using Modbus. I have visited several electrical rooms that have gateways installed ...
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Puzzle how isolated RS-485 (ADM2582) sends signal without signal ground
Galvanically isolated RS-485 surely needs a signal ground, which leaves me puzzled about the following circuit -- which apparently sends the RS-485 signal correctly without the isolated grounds being ...
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What technology to use with multiple embedded systems talking to each other?
I am planning on building a system with one master and multiple slaves using MSP430 microcontrollers. The microcontrollers must talk with each other with serial interface using RS-485. I now need to ...
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How is SM712 TVS array suitable for use with MAX485 in an RS485 driver circuit?
I have an RS485 driver circuit consisting of a MAX485 driven by an STM microcontroller. I was looking at TVS diodes for basic protection from electrostatic surges from wiring and handling, and found ...
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RS232 and RS485 sharing same wires
I'm planning a serial port that can either work as RS485 (half duplex mode) or as RS232 (configurable by the user).
There are several UART to RS232/485 chips around (like LTC2873), where a GPIO ...
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Can TCC-100/100I Series Industrial RS-232 to RS-422/485 converters with optional 2 kV isolation convert RS485 to RS232? [closed]
I want to convert RS485 to RS232 to connect it to a Moxa Nport 5610 - 16 port RS-232 Ethernet serial device server.
Can I use a TCC-100/100I Series Industrial RS-232 to RS-422/485 converter to convert ...
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How to connect RS-422 to 2× RS-485?
I want to connect two Arduinos via RS-422. I have 1 converter RS-422 to TTL and two RS-485 to TTL. How I can connect outputs of my converters (Y,Z,B,A on MAX490 and A,B on MAX485)?
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RS485 isolated or not for home automation system?
I'm creating a home automation system for condominiums. Practically there are a series of control units that communicate with remote sensors. Communication takes place via RS485 serial on an Ethernet ...
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Response partly lost in Modbus RTU over RS485 communication
I have developed a Modbus slave which uses ATMega8A and MAX485. In a new lot of the devices, while testing them on my PC using QModMaster, the response that I get has one byte in front of it, and cuts-...
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Can I use LED on the actual RS485 bus?
How bad of an idea is to put a LED on the actual RS485 bus AB lines, for indication of activity on the bus. Something like this:
I know people would say why not put LED on 'Recieve' and 'Drive' pins ...
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Pulling Receiver Enable Low for RS-485 Transceiver is being transmitted as a byte in Modbus packet
I am running into an issue where pulling RE low on my Max3441EESA is appearing as an extra byte in my Modbus message. I am currently testing the Modbus capability of my PIC32 MCU with a Modbus slave ...
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RS485 Wiring and Enables
I have an sensor with an RS485 interface that has a pinout with labels V, GND, A and B. In my system context, there will just be this one sensor and an ESP32 microcontroller running on 3.3V to ...
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Connecting a non-galvanic isolated RS-485
I would like to consult if I am designing RS-485 connection correctly without risk of damaging anything.
Main goal: I want to get data (e.g. flow temp) from Danfoss ECL 210 district heating control ...
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Is 74244 buffer suitable for multiplying data and enable in my Rasberry Pi3 to ATmega128A bidirectional communication?
My Raspberry sends data at baud rate 115200 to 300 remote panels (ATmega128A) through RS485 bus serial communication.
Also it sends enable signal (5 V) and receive feedback from the 300 panels at the ...
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How fast can a Schmitt trigger operate? Can I use it for signal conditioning digital serial data?
I would like to know if I could use a Schmitt trigger chip (e.g., 74HCT14, CD40106B and 74AC14) to clean a 12MHz serial digital signal that has gone through a long cable and will pass through multiple ...
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Potential Reasons for Fault on RS-485 Transceiver
I am working with the MAX3441 RS-485 transceiver, but I have run into faults with the three transceivers I have tested, so I am wondering if anyone can shed some insight on potential reasons for the ...