Questions tagged [rs485]
EIA RS-485 is a serial communication standard using differential signaling.
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Is there any way to convert RS485 to K-line (ISO 9141)?
I'm trying to build a touch panel interface based on a WT32-SC01 PLUS to control my Webasto heater. The WT32-SC01 PLUS contains an RS485 interface and I would like to know if it is possible to build a ...
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Need help understanding this UART to RS485 adapter circuit
I am trying to understand how this circuit works.
Below is the explanation provided in the manual I am referring to:
"Receiving data: P_TX is in idle state, which is high level, transistor ...
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Half Duplex RS-485 to Modbus communication [closed]
I am having trouble to determine how to wire up my RS485 half duplex to a Digi One IAP from an Atlas Copco Modbus Gateway.
From Atlas Copco, the gateway needs is setup to use RS-485 Half duplex, no ...
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Modbus ASCII messages delimiter
I need to implement Modbus messages reception over UART. For RTU it's easy because UART on my uC has configurable idle receive line detection. However, for ASCII the task is tricky - the delimiter is ...
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RS485/RS422 Buffer position
I have a doubt, when I have a circuit that has a driver for a serial interface, such as a TTL-to-RS485 or TTL-to-422 buffer. The typical situation I'm in is that this chip is connected on one side to ...
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TTL to RS485 using MAX485 - Capacitor voltage requests
I need to implement a TTL to RS485 converter into an home made project and searching by Google I found this module with related schematics:
Could you help me by indicating the correct voltage for the ...
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PIC16f RS485 reception ok, transmitted data incorrect
I am currently working on a RS485 communication, I use a PIC16F18855 and a THDV1505.
I communicate with my computer using a USB/RS485 converter.
The PIC receives the data well, but I have a problem ...
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Modbus RTU on ESP8266 to control VFD
Hoping to get some help on setting up a NodeMCU (esp8266) with this 1 arduino library to control a Variable Frequency Drive (VFD).
I'm afraid to say that I almost need help from square one, as I'm ...
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Why is my circuit powered by a 24 VAC -> 5 VDC stepdown module releasing the magic smoke?
I have a Carrier HVAC system in which device controls are all powered by a 24 VAC pair and communicate via an RS485 differential pair.
In the past I've communicated with the bus by using USB to RS485 ...
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How to record analog signal of a RS485 bus with a pocket Oscilloscope / Logic Analyzer with ADC (limited input voltage range with voltage divider?)?
I need to debug an RS485 bus (record analog signals) on a remote installation with a pocket Oscilloscope or Logic Analyzer. Can I simply use a voltage divider to bring down the RS485 signal to within ...
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RS485 to CAN transceiver converter
I am using an ESP32 that has a CAN transceiver on it. I want to be able to communicate with an RS485 device.
Below is a block diagram of the high-level schematic for this:
Can someone assist with ...
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RS-485 4-wire to 2-wire converter
I'm looking for a way to be able to electrically switch between 4-wire and 2-wire RS-485. Up until now I have used jumper connections to establish both communication ways with one circuit. But I would ...
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Read Hikvision camera on PC over RS485 [closed]
I have a Hikvision IP camera. I can login onto the camera and stream live video through hikvision website.
However, the connection of the ip camera to the PC is via ethernet, which is limited to only ...
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Are there advantages to using differential RS485-like communication between two MCUs using digital GPIOs only (without transceiver)?
I have two MCUs and two wires between then. Currently these wires are used as I2C and work well, but we expect bursts of noise and want to protect against it. I am thinking of converting from I2C to ...
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Why does this 7-in-1 soil sensor print mixed values?
I'm working with a JXCT-IoT seven parameter soil sensor.
I did tests to print each parameter and it prints the correct value but when I put in all the code, the values are mixed. For example, the ...
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Overvoltage protection for RS485 from DC-DC voltage
I am making a circuit to protect RS485 against 24V and 32V DC over-voltage. Note that my power supply is 12V. I've done my research and found solutions, but I can't fake it.
More specification ,my ...
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Serial circuit protection design
I've been researching RS485 hotplug protection for a while and come up with the following solution. The reason is that I burned two custom Arduinos, after further investigation it turned out the GND ...
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What are the correct signal ground connections in an RS485 system with a shared ground on motor drivers?
I'm in the process of designing a motion control system using RS485 and whilst we've generally made things work in the past with a more trial and error approach, in the interest of doing things right ...
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RS485-Protection(signal (A-B) from input voltage (12v and 24v )using TVS diode
To protect RS485 signals differential (A/B) from power input (12 and 24 V), we can use TVS diodes.
TVS diode parameters:
There are many types of TVS diode in the market, designed for a specific ...
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How to switch between multiple signals
I have a board that has a MAX232 and a MAX485. I want to switch between these peripherals' RX/TX signals which connected to Arduino. How would I achieve this?
I am definetly not knowledgeable about ...
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How to connect USB-to-RS485 adapter to RS485-RJ45 input of an LFP battery BMS? [closed]
I have Victron Multi 48/5000 connected to Cerbo GX. Works fine.
Now I need to connect Cerbo GX to the LFP battery, to RS485 (because no CAN input).
...
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RS485 connection
I have 6 TTL to RS-485 modules and I want to connect them in a way that disconnecting any specific wire from a slave module would only affect that one module, and the rest of the circuit should work ...
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STM32 Nucleo RS-485 connection
I want to communicate device with RS-485 bus with STM32 Nucleo-F767ZI.
I have an RS-232 to RS-485 converter powered with 12V and connected to device A, B. Will it work if I connect RS-232 side TX RX ...
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RS485 communication circuit review
We are working on RS485 communication. We have designed the schematic as shown in the image. We are using TI's THVD1520 IC.
Is the logic of the circuit correct? We are concerned about the 2nd and 3rd ...
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RS485 transceiver bus output error (ADM3065E)
What could cause the A and B outputs of a RS485 transceiver, in this case the Analog Devices ADM3065E, to drive high simultaneously when asserting the driver enable?
The Situation:
I have a RS485 bus ...
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TTL to RS485 board blowing up
I recently started to explore energy meters with the ability to transmit data over RS485.
The specific meter I'm using is an Eastron SDM72D V2. I made a simple program to request data from the meter ...
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RS-485 bias & termination resistors with 3.3v transceiver and 100 ohm cable
I am trying to connect two boards together with a few feet of Cat 5e cable. Both boards will be using 3.3v RS-485 transceivers (ISL83483 or similar).
Using this calculator, I entered 3.3v for supply ...
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Do FTDI serial port chips use a soft UART, or a hardware UART?
I'm considering using an FTDI cable for RS-485, and I'm wondering who controls the driver enable and how. Is it in a hardware UART, a soft UART, or by the PC the USB is plugged into (very unlikely).
I'...
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What protocol is this waveform?
I'm trying to reverse engineer a communication line between two components. However for debugging I'm connecting to only one of them, powering it up and looking at the signal. I have no experience ...
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MAX485 wrong data output
I want to convert USART signals to RS485 with the circuit below:
I log the data on the USART6_TX and 485A/485B at the same time, but the data on the output pins of the MAX485 is wrong and it's not ...
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Assistance differentiating between RS485 transceivers (for use with Arduino slaves and master Pi)
I'm trying to spec out a project and get a shopping list together and am hoping to get some advice which parts to buy. The Pi will serve as the master and connect to a few arduino's at first, but I'd ...
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Different types of RS485 circuits
I've seen in some schematics that the RX, TX, RE and DE pins are connected to VCC with a resistor. This is how the connection with the UART pins is made (see schematic below).
In some schematics, ...
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Calculate RS422 signal to travel time from one side to another
I want to calculate the time take to transfer command from one uC side to another,
this is the architecture:
the Baudrate is 115200,
the number of bits is 8.
I would like to hear explain not just an ...
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Connecting 12 V RS485 appliance (soil sensor) to USB 5 V RS485 adaptor
I have a 12 V RS485 appliance that measures some soil resistance etc. It is a 7-in-one soil sensor, the 12 V version of the 5 V version shown in the link.
I could not find a 12 V USB to RS485 adaptor ...
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Is it possible to use an RS232-USB cable (with an FT232RL chip) for RS485-USB communication?
I have a standard RS232 to USB cable found on Amazon.
It does not work out of the box. This is what I expect since RS232 uses a ground reference and RS485 uses a differential between the two data ...
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Identify round RS485 connector
I'm going to get a solar inverter. It has a RS485 port on a round waterproof male connector:
The diameter of the mating female connector shell seems to be about the same as a MC4, or 19mm.
I'm ...
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UART to RS-485 communication between two Arduinos
I'm learning how to use a MAX485 or MAX487 IC to create a half-duplex RS-85 communication between two Arduino s.
Each Arduino has an LED that turns ON/OFF by receiving a command from the other Arduino....
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MAX485ESA RS-485 doesn't work [closed]
I have my own PCB with MAX485ESA+ chip to use it as RS-485. I draw it similar to UART TTL to RS485 Two-way Converter.
If I connect it with ROCK PI S UART3 and Single-phase Smart Power Meter, I can't ...
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What is SN75176 receiver pin drive current?
I am poor at understanding what datasheet symbols denote. Please help me decode what might be the drive current of receiver logic pin.
Here is the link to datasheet: https://www.ti.com/lit/ds/symlink/...
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Flashing an ATMega microcontroller using a USB Connection
I'm trying to get into embedded system design and have been hung up on what hardware is required to use a USB connection to communicate with the microcontroller (and therefore, flash it). Here's what ...
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RS-485 possible ground loop
I am trying to develop a sensor network for a rainwater collection system. The setup consists of four "nodes" and a master, where each node has an ultrasonic distance sensor to measure the ...
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Which instructions do I use to be able to use UART directly on my STM32F107 microcontroller?
I've tried to figure this out on my own but after almost a week I'm still at more or less the same place where I started. So, I have an STM32F107 microcontroller on a board, which is linked to another ...
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Using CAN with Teensy 4.1 is better than using RS-485 which requires extra converter?
I am using Teensy 4.1 and need to communicate with motor driver which supports CAN and RS-485.
In teeny4.1 CAN is supported yet it requires CAN transceiver whereas if I want to use RS-485 I need to ...
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Which data transfer speed (connection protocol) do I need?
I have 124 sensors that sense analog signals ranging from DC to 25 kHz.
Analog data is converted to digital with a resolution of 16 bits. The ADC I am using is the AD7656 with a data rate of 250 kSPS, ...
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Isolated RS485 without specialized IC
I'm looking for replacement for ADM2587E.
This is ADM2587E:
Can I just use cheap, not isolated RS485 transceiver like MAX485 connected to microcontroller TX, RX, DE/_RE via optocouplers and power it ...
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Is this a legitimate RS485 wave shape?
I'm having issues but first of all I need to verify the other end of the communication line… there is a Moxa TCC-100 RS232-RS485 converter attached to the bus and I see this weird signal on the bus ...
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How does this RS485 transceiver work?
I'm attempting to communicate with an RS485 network with a raspberry pi pico, and I found a "hat" which includes a couple SP3485 transceivers, along with the supporting TVS diodes, etc. The ...
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RS-485 Network Topology with Backbone and Daisy-Chain Stubs [closed]
I am designing a RS-485 network and would like to know whether the configuration below would work. The transceiver I am using is the Maxim MAX485, with the master ad slaves hardwired to always ...
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CAT6 for both RS485 and CAN in same cable
I have two devices which need to talk to two controllers about 60m away in the garden.One uses RS485 and one uses CAN.
I have to run armoured CAT6 for this and wondering if I can use the same run for ...
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MCU working at 3.3V and RS485 driver at 5V - how does this circuit work?
I was looking for a "quick and dirty" solution in order to work with MAX487 (5V) and my ESP32 MCU.
I know that Maxim integrated produces the MAX3485 and MAX3483 that are specifically ...
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