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Questions tagged [rs422]

RS-422 is a point-to-point serial communication bus using differential signalling to achieve high data rates.

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UART and RS422 Interfacing

Do I have to connect the Logic side of an RS422 transceiver to a UART on my STM32, or can I connect the logic side to any GPIO on the STM32?
Dark-Matt19's user avatar
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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)?
Рома Рома's user avatar
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Why would a low-pass filter be connected to +5V on an RS422 differential line?

I am interested in a datasheet's schematic for my own PCB design of a similar system. In my system, I am receiving an RS-422 differential line, and would simply be tempted to put a 100 Ohm terminating ...
Tommy95's user avatar
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Understanding RS422 and choosing drivers

I want to communicate 2 MCUs using RS422. I need to have some isolation, so the driver should have 3.3V side and 5V side, isolated. All I can find in the market are half-duplex drivers, I understand ...
Developing Electronics's user avatar
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Interfacing RS422 with microcontroller

I want to use RS422 to communicate two MCUs. In a serial protocol, RX from MCU1 goes with TX from MCU2 and viceversa. RS422 is differencial, so I don't really know how to manage this. Where do I ...
Developing Electronics's user avatar
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How should I layout an optocoupler isolation board with separate ground references and power supplies?

I am thinking about how to layout my opto-isolation board. It is used to protect pins on an FPGA, convert signals to RS-422 and then transmit via RJ-45. I have seen some conflicting information about ...
Friizzle's user avatar
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How should I choose TVS diode capacitance for my 2MHz RS-422 application?

I have been looking at which TVS diode to select for a protecting a set of RS-422 driver lines, however I am struggling to understand how to choose them based on the diode capacitance. The signal will ...
Friizzle's user avatar
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How to convert RS-422 paired-signals to one CMOS signal

I am able to find several commercial ICs for converting CMOS or TTL input levels translate to RS-422 output levels. (I.e One 5V single input to two differential output). However, I couldn’t find how ...
Xant's user avatar
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Physical modification of RS422 to ensure one-way dataflow

Is it possible to physically modify an RS422 connection such as by removing Pins from the terminals or physically cutting the wires so there is zero possibility for return data flow. I have one device ...
Joseph G's user avatar
2 votes
1 answer
176 views

How should the gas discharge tubes for RS-422/RS-485 be placed and routing on the PCB?

I adjusted the gas discharge tubes to be close to the connectors on the PCB. The RS-422 lines have a differential line impedance of 100 Ω. My concern is, aren't the lines between the connector and the ...
Electronx's user avatar
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Convert Composite Video to RS-422 [closed]

I misinterpreted my requirements and asked the question below, which does not make sense. I am designing a Digital (TMDS/HDMI) to Analog (Composite) video circuit. I am almost to the end. The last ...
miggyEE's user avatar
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Placement of USB/UART converter for robustness and noise immunity: long USB cable or long EIA-422 cable

Consider the very common case of communication between the UART peripheral of a microcontroller and a PC, using a USB-UART converter such as are available from FTDI and others[1]. If there's a non-...
Ben Voigt's user avatar
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How is the 3 terminal gas discharge tube grounded for rs 422 protection?

I took over an unfinished project. Here, gas discharge protection is used for rs422 protection. 2 different grounds are used in the project. And the middle point of the gas discharge tube seems to be ...
Electronx's user avatar
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RS422 + DI2C on same cable

on my system I need to connect two devices together, these devices have an RS422 interface and a DI2C interface (differential i2c, PCA9615 driver). Both RS422 and DI2C need 2 pairs. The question is: ...
Federico Massimi's user avatar
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2 answers
269 views

RS422 CAT5 Cable shielding connection

I have a question about shielding an ethernet cable. I have to go from point A to point B with a CAT5 or CAT6 ethernet cable, the cable is used for a RS422 link (two pairs). On the sides of the cable ...
Federico Massimi's user avatar
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Can I Use RS232 Library For RS422 in PIC Microcontroller?

I have this project where I have to use RS422 and Max485 serial communication. The task is simple: The input from 15 buttons should be send to PC by RS422 using PIC18F4620. I have no experience in ...
Line Follower's user avatar
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Common mode choke on RS422 line

A question about the RS422 interface, is it necessary to have a common mode choke on differential lines? I ask because in all the guidelines I've read the need a common mode choke is never addressed, ...
Federico Massimi's user avatar
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498 views

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 ...
Knowledge's user avatar
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1 answer
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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....
a2640's user avatar
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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/...
Bubu's user avatar
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1 answer
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Connecting a radio device with controller (+ power supply) [closed]

I have a min knowledge in electronics, so I am sorry if my questions are stupid for you. I am studying how I can connect a radio device with a controller. The radio device is a transmitter/receiver or ...
FrimHart64's user avatar
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2 answers
951 views

Single-ended digital signal to RS422 differential signal

I'm trying to control a laser scanner from an Arduino board. The Arduino outputs a single-ended digital signal 0V or 3.3V. The signal I'm transmitting to the laser is the same signal as I use to ...
Blims's user avatar
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How to make a multupoint RS422 connection for serial communication?

I need an RS422 multipoint connection. When I tried connecting it as shown in the image the communication didn't work, but when I connected all the devices' pins T+, R+, T-, and R- i.e T+ of one ...
Amrutha kn's user avatar
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Using one twisted pair of ethernet cable as control signal

I am designing a system based on this application note of TI. The overall design goal is to have multiple shift registers, connected via RS-422 and ethernet cables over fairly long distances(up to 5 ...
Dennis Ernst's user avatar
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2 answers
278 views

Convert HTL to RS-422

I have to convert a 0-24V (HTL) signal to a RS-422 signal. (It's a signal to enable data acquisition on a device that requires RS-422). We found a device from Motrona (PU210) that converts our HSL ...
Simon's user avatar
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What makes signal lines hot swappable?

In MAX14780E datasheet, it's explicitly featured as "hot swappable", however in AM26C31 datasheet this isn't mentioned. Moreover, I suspect that I burnt one of the AM26C31 ICs while hot ...
ceremcem's user avatar
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What is the likely power consumption for the SP3070EEN RS422 Transceiver under normal operating conditions?

I am designing with the SP3070EEN. SP3070 Datasheet I've tried to calculate the power consumption that this IC is likely to use when transmitting under normal conditions. I ended up with ...
lgflorentino's user avatar
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466 views

RS422 - Hot swapping - fuse blowing up - tvs?

I have an issue with the following schematic: When I am doing a hot swapping on the RS422 (Local console) connector X1200, my fuse F1200 blow up. I have a TVS diode to protect against overvoltage on ...
Armand's user avatar
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Can I use two arduino output pins to simulate a RS422 trigger?

I have measuring wheel encoder like this one, which outputs its position using two RS422-encoded pin pairs, standard quadrature encoding. Note that these are not using the RS422 communication protocol,...
Guntram Blohm's user avatar
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Using an Ethernet Phy and XFMR instead of RS422

We've been using a quad RS485 setup for some time. No problems. Now we'd like to increase the speed over what we can get away with on RS485 with the micro we're using. Essentially, we've been ...
GaryLa's user avatar
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1 answer
323 views

How to add remote testpoints to non-multidrop RS422 without causing reflections?

I have a RS422 non-multidrop connection between two connectors on a PCB (CLK+/- and DATA+/-) clocked at 1MHz, and currently routed with adapted edge-coupled microstrips (120Ohm differential impedance)....
Mister Mystère's user avatar
1 vote
3 answers
828 views

Differential (RS-422) vs current mode signaling in noisy environments

I’m building some automation equipment for my shop that will be used in extreme noise environments (plasma cutting and TIG welding nearby, for example) and I’m trying to come up with the best ...
Ben H's user avatar
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Conversion SSI to SPI

I want to interface an encoder based on the SSI interface with a microcontroller and only an SPI interface is available (I can't use other interfaces than SPI). As far as I see, SSI has a lot in ...
Marco Svizzeri's user avatar
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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 ...
Sven's user avatar
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2 answers
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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 ...
EmbSysDev's user avatar
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What limits the maximum number of nodes of a RS422 bus? How to check if N>10 nodes is possible without repeater?

I have 13 identical devices which communicate with a host via RS422. None of them are addressable (they assume point-to-point connection). I would like to string them in a RS422 bus. I thought of ...
Mister Mystère's user avatar
1 vote
3 answers
299 views

Decode rs-422 without line receiver

I have a encoder on a dc motor that outputs it's signals as RS-422. A, ~A, B and ...
John Smith's user avatar
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4 answers
11k 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 ...
alt-rose's user avatar
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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, >...
eudoxos's user avatar
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0 answers
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Different frequencies of digital signals over long distance

I am working on a solution which will need to transport some different frequencies of digital signals over 10-20 meters. I have worked out a design with the following components: PCB with An ESP32 ...
Jeroen's user avatar
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4 votes
4 answers
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Is a ground connection needed in between master and slave for this RS485/422 scenario?

I will work on a small project where an SSI-output data (angle data) of a rotary-encoder will be read by a micro-controller board (such as an Arduino board) and the micro-controller will then send ...
floppy380's user avatar
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How to identify 422 or 485 bus from the PCB

I have a very old CPU card, maybe 1980's. It has following chips on it and most probably these are used for communication with the rest of the system. SN55188 Quad Line Drivers SNJ55189 Quad Line ...
alt-rose's user avatar
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Interfacing LEDs at communication lines for a RS232 to RS485/RS422

I want to use LEDs at the output of R232 to RS485 & RS422 converter to indicate the Rx and TX activities. This converter will be inside an enclosure and I want the RX TX activities to be indicated ...
cm64's user avatar
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3 votes
2 answers
766 views

RS422 Receiver Not Reporting Errors When Too Few Stop Bits

I am interfacing with a device (the transmitter) which configures its serial settings to 8 data bits, no parity, 1 stop bit at a baud rate of 115200. These are known values and fixed values I can't ...
Trenton Holmes's user avatar
2 votes
1 answer
5k views

RS422 and RS485; full-duplex or half-duplex?

I have extensively used RS232 transceivers in many projects and have fairly good understanding of UART communication using RS232 transceivers. MAX232 and MAX3232. Now I have to build my understanding ...
alt-rose's user avatar
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RS422/RS485 data input series resistor

I am using an RS422/RS485 driver to send Arduino 5V logic data over longer distances. I use the SN75174 driver for this purpose. In order to avoid ringing, I am not sure if I have to connect a series ...
F. Heisenberg's user avatar
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3 answers
2k views

RS422 Full-Duplex Cable Shielding

I need to interface two PCBs via RS422 (250kbps) in full-duplex mode (4-wire, 2-twisted pairs 100ft cable). This system will operate in a noisy (CNC) industrial environment, ie, industrial controls ...
Steve's user avatar
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Questions about RS422 driver

I am using a GPS receiver board which transmits a PPS signal into a TTL <-> RS422 board I need to design. The receiving end (of the RS422 signal) is 15-20 meters away. Here is my design: My ...
nettek's user avatar
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1 vote
2 answers
9k views

Connect RS422 interface with Arduino Uno

I have a fishfinder,Lowrance Carbon HSD 7, and I want to connect it with the Arduino Uno to let the fishfinder transmit the Sonar data and GPS data via NMEA0183. According to the maker's site, the ...
RexSolus's user avatar
  • 113
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2 answers
167 views

Help figuring out the interface on this bill validator?

I would like to interface this bill validator to a microcontroller (Arduino Mega). The website says it supports RS232,RS485,Optoisolated RS232 and USB interface. The one I have is currently intefaced ...
B. Cleo's user avatar
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