Questions tagged [rs485]

EIA RS-485 is a serial communication standard using differential signaling.

Filter by
Sorted by
Tagged with
0
votes
3answers
64 views

Connecting 50 Arduino slave devices to a single master Raspberry PI

I am designing a automation system and need to have multiple slave devices(probabaly arduino UNO or NANO) communicating both ways with master device (Raspberry PI). There is a server and database ...
0
votes
1answer
24 views

SC18IM700 operation (RS485 to UART to I2C)

I need to create a circuit to talk to a piece of equipment using the I2C bus. I'm on a PC that has an NI serial card with RS485 ports(I'm not sure of the model number off the top of my head). I ...
0
votes
2answers
41 views

RS485 Input Hysteresis

What is the meaning of Input Hysteresis in the context of a RS485 transceiver? Thanks
0
votes
0answers
29 views

RS485 Trancievers: ADM2483 VS ISO15

i'm actually doing some hardware selection about RS485 trancievers. There are a lot of different suppliers, drivers, etc... So, i've selected these two trancievers: ADM2483 from Analog Devices and ...
1
vote
0answers
26 views

How to light LEDs for serial data from Arduino over RS232 [closed]

I am a newbie to electronics and Arduino. I am in need of help. Any help will be greatly appreciated. Here's is my problem statement I want to light up 8 LEDs based on the serial data sent by arduino ...
1
vote
1answer
74 views

Glitching on UART RX line with RS485 transceiver

I have a custom PCB which has a RS485 transceiver chip interfaced to a Nordic microcontroller. I essentially have a daisy-chained arrangement of RJ-11 ports which are carrying the RS485 A/B signals as ...
1
vote
0answers
57 views

How are DC offset square wave transmission waveforms generated?

The balanced serial transmission shown in the picture is similar to rs485 except that the square wave has a DC offset (e.g. 24VDC) with an alternating offset. The transceiver chip "drives" ...
0
votes
1answer
67 views

RS422/RS485 termination and noise immunity

Consider a RS422/RS485 receiver like the AM26LV32 or the DS26LV32. It is used to receive the signal of incremental encoders with differential outputs. Assume that those are using drivers such as the ...
0
votes
1answer
52 views

Switch “On”/“Off” RS485 data lines

i'm doing some researches about how to close/open RS485 data line in my RS485 multi device bus. I'm following this nice research-document: Link Here. Basically i'm thinking how to solve this problem ...
4
votes
1answer
117 views

RS485 transceiver design: Bias, termination, filter and protection

For the realization of an RS485 transceiver, I came across the question: How can bias, termination, signal filter and protection be best implemented in one design? In my case, one RS485 master (with ...
-1
votes
3answers
53 views

Protocol with twisted pair for multiple switch control in a tree topology?

For an irrigation system, I'm interested in simple switches. My requirements: Communication over copper wires, e.g. a twisted pair of cables Nodes(switches) can be set in a tree topology, all sharing ...
0
votes
1answer
47 views

TVS diode for RS485

I'm studying the ISO1500 for an RS485 application. In particular, I'm looking for a TVS diode for bus protection. I've found that a common TVS diode used for RS-485 applications is the SM712 (like ...
1
vote
0answers
50 views

MAX487 can transmit but won't receive

I am trying to use a MAX487 chip to convert a regular UART signal to half-duplex RS485 signal and vice versa. I am using Atmega328PB as my micro controller. My circuit has no problem with transmission,...
6
votes
3answers
1k views

Could Cat5e be used for RS485 [duplicate]

I'm working on a project that will be using RS485 to communicate between a bunch of modules and a master controller. Low baud rate, 9600, but a decent distance, like a couple of hundred feet. I'm ...
1
vote
1answer
47 views

FT4232H: Configuring RI# as TXDEN Using FTProg

I am developing a device based around two FTDI FT4232H quad USB-to-Serial converters plugged into a Texas Instruments TUSB2046 USB hub controller. The serial outputs of each FT4232H channel goes to a ...
0
votes
1answer
61 views

ADM2483 or MAX485 Design: Modbus RS485 RTU bus in harsh environment

I'm currently out of ideas, i have a simple Wigoneer RS485 TTL interface (Sch link here) with MAX485 wired to my ESP32 based board, in my lab everything works like a charm with 1300 meters of CAT6 UTP ...
0
votes
1answer
43 views

Re : RS422 module from Aliexpress

Was planning to work on some long distance communications with RS485 / RS422 and I saw one of these boards on Aliexpress,Amazon etc.. Does anyone know what all those passive components could be? Would ...
0
votes
1answer
48 views

Long Range (100m) USB(PC) to USB (microController USB module) Communication

I have a system that communicates between PIC32MX250F256D (USB module) and PC via USB (2 meters apart). And I need to increase the range of this communication to 100 meters. Due to typical 5m limit of ...
0
votes
1answer
66 views

Sniffing an RS-485 communication

I am trying to sniff a serial communication between two devices. One of them sends a command (6 bytes + 2 bytes CRC), the other one responds (4 bytes + 2 bytes CRC). My computer monitors the exchange ...
0
votes
2answers
40 views

Effective differences between MAX485EESA+T and MAX485ESA+T?

Is anyone able to explain to me the effective difference between the MAX485EESA+T and the MAX485ESA+T? The datasheet points out that is more tolerant of ESD discharge up to 15kV, nothing more. Can ...
1
vote
1answer
19 views

RS-485 device to RS-232 adapter MUXing not working as expected

I have a RS-485 device that returns serial ASCII constantly. As the device might near very high voltage or electromagnetic areas, I need to ensure the RS-485 to RS-232 adapters I've been supplied with ...
0
votes
1answer
40 views

How to increase data through put of RS485 RTU?

I am using 20 sensor nodes, each has mpu9250 i2c, Arduino atmega328 MCU 8MHz and max485 chip in it, each slave has a unique id program. I have Arduino due as Modbus master with max485 chip, I hope ...
2
votes
3answers
1k views

Why single ended signal line is not immune to noise in RS232?

In single ended signal line the measurement is the difference between the signal and the ground. Isn't this way of calculation make it differential? Almost all the resource I have read says that ...
3
votes
2answers
63 views

Wrong output using SN75HVD10 (RS485)

Designing a modbus master using a STM32F030CCT6 and a SN75HVD10 (3.3V). This is the schematic When i send the following message from the UART: 01 03 00 00 00 06 c5 c8 I see the following scopes (...
2
votes
1answer
65 views

Using CANbus cable for RS-485

I have a question regarding an application with a Modbus RTU network. I would like to know if it's possible to use a CANbus cable instead of an RS-485 cable? Here is a picture of the cable:
3
votes
1answer
49 views

Is it possibile to use a CAN transceiver to send RS485 data?

Looking at the signal ranges I'm not sure if I can use a CAN transceiver (not controller!) to send data to a single RS485 device.
3
votes
1answer
38 views

Is there some kind of standard of modbus input register?

As the title said, based on your experience, is there a such thing? If no, which are the most commonly used? for example in a sensor, the input registers as follows: ...
0
votes
1answer
62 views

USB to RS485: Can I connect A to Common Ground?

I bought a very cheap USB to RS485 dongle to connect to an experimental board of my own. Specifications (may differ from the one I used but externally similar): - Any baud rate from 1200 bps to 115 ...
0
votes
0answers
165 views

RS485 Pull-up, Pull-down and single termination resistor

Currently I use for Modbus RTU via RS485 with a shielded cable length of about 5 meters and a bitrate of 19.200 bit/s. Wired are 680 Ohm pull-up (A->+5V) and pull-down (B->GND) resistors near to the ...
0
votes
1answer
58 views

Can power supply be chained?

In my current project, I need to communicate and supply current to 4 sensor PCBs ("S1", "S2", "S3" and "S4") from a master PCB ("M1"). I will use RS-485 to communicate between PCBs, meaning I can ...
0
votes
0answers
33 views

Rs485 all nodes not communicating

I am Using a gateway etor-4 to convert Rs485 to ethernet and then provide data to Modicon 580 cpu.My slaves are tm221 controllers which are 22 in number.The problem is I can get only 5 nodes data ...
1
vote
2answers
131 views

Use half-duplex or full-duplex RS-485?

I have a master microcontroller that can control 4 slave microcontrollers. Each slave microcontroller is connected to 3 sensors. The master microcontroller asks to retrieve the value of a specific ...
0
votes
3answers
112 views

Why lines A and B are HIGH when idle (rs485)

I'm using modbus RTU over RS485 for a project. I use a RaspberryPI as master and Arduino Pro Mini as slaves. My problem is the following : I plug a sensors on the bus and it returs its value. I plug ...
0
votes
1answer
42 views

How to wire up GSM Modem(DCE) With MAX485

I am trying yo figure out how to directly connect a GSM modem (say SIM800) with a MAX485 . The purpose of this is to make an RS485 GSM Modem. I am struggling how to wire it up, do i wire the CTS of ...
0
votes
0answers
12 views

XPort Edge (web manager) access denied with default credentials

I have the Xport EDGE connected and powered using the evaluation board. I'm trying to use an XPort EDGE as a means of connecting an embedded device to the internet. It uses RS485 (That's the ...
0
votes
1answer
49 views

GSM Module + RS485 transceiver possible?

I was wondering if someone could confirm if it is feasible to interface a GSM module for example SIM900, SIM900, Quectel's M95 or Neoway's N10 , maybe if we use the RS232 interface with HW the flow ...
0
votes
1answer
60 views

RS485 communication between Arduino

I want to transfer data (only numeric values) between Arduino Nano and Arduino Mega 2560. I tried with my own code and tried with several libraries also. Arduino Nano code ...
0
votes
1answer
85 views

Noisy RS485 signal with MAX13487E and Raspberry Pi

I am trying to use the MAX13487E RS485 transreceiver with a Raspberry Pi 3 B+. I chose this chip specifically because it does not require a RTS signal, which is complicated to setup on the PI. My ...
3
votes
0answers
152 views

Replacing the physical layer of MIL-STD-1553 with RS-485

I've been reading about MIL-STD-1553 buses, which very briefly are multidrop Manchester-encoded 1 Mbit/sec 32-station: a single "bus controller" master and multiple "bus terminals" slaves which speak ...
3
votes
1answer
223 views

Decoding an unknown serial bitstream that does not fit 8-N-1

I am looking at an RS-485 signal using a scope and an analyzer (saleae). This is running a mystery bus (see below for more information). I would like to know how to fix my frame errors. I can't begin ...
6
votes
2answers
145 views

RS485 Common Ground: Common Voltage or Common Wire or Both?

RS485 connection needs a common ground, but I am very fuzzy about how that works over longer distances and more complex systems. When the transmitter and receiver are about 1000m apart, there will be ...
0
votes
4answers
385 views

RS422, RS485 Termination Resistors

While going through this youtube video from TI about the RS232, RS422, RS485 differences. One thing that don't understand clearly is following slide from this video. The blue resistors that I marked ...
0
votes
0answers
77 views

RS485 - Comunication lost during EFT IEC 61000-4-4

I'm having throubles with communication over RS485 in harsh industrial environment. We perform test in EMC lab, acording IEC 61000-4-4 = Fast transient (also known as Burst). We used burst generator ...
0
votes
2answers
75 views

1-channel GPIO from industrial PC over RS232 port

I am ordering a computer based on 4x4-R1000V motherboard (Ryzen Embedded, https://www.asrockind.com/overview.asp?Model=4X4-R1000V) for an industrial application. I need a 1-channel GPIO (0 for zero, >...
1
vote
2answers
79 views

Please help me understand modbus communications

I'm just starting out with understanding how modbus works over a rs485 protocol. I've received a communication protocol document from a company that makes solar inverters. I want to send a command ...
0
votes
1answer
253 views

Isolated Modbus (RS485) ground and UART noise

I build an isolated RS485 (Modbus) interface board for a sensor. I use ADM2682 as transceiver and VAQE6W-Q24-S12-D as isolated DC-DC converter. All is managed my a STM32L412. There is 2 interesting ...
0
votes
1answer
61 views

How would I connect an HC-06 bluetooth module to an SN75176A RS-485/422 transceiver?

I am trying to fashion a small module that would allow me to connect to an RS-485 system via Bluetooth. I have found that the potentially cheapest solution would involve an HC-06 TTL Bluetooth ...
2
votes
1answer
56 views

Modbus: Sensors timed out when plugging another sensor

I have created an hydroponic system using modbus to communicate between a RaspberryPI server and plug&play arduino sensors. It works but as soon as I plug a sensor on the bus (physically), all the ...
0
votes
1answer
47 views

Questions on connecting and using the RS485 MAX14783E transirver

Task: Using Arduino UNO, obtain various parameters from the ABB B21 112-200 electric energy meter, as well as send settings to it. This meter has an RS485 interface (ModBus RTU) with terminals A, B, ...
0
votes
2answers
61 views

How to connect a few shields correctly?

There are several shields on my PCB: shield on CAN-bus, on RS485, on Ethernet, on ENCODER motor signals. How do I correctly connect all these shields? If I use the star topology, which filters should ...

1
2 3 4 5
9