Questions tagged [rs485]
EIA RS-485 is a serial communication standard using differential signaling.
107
questions with no upvoted or accepted answers
4
votes
0
answers
534
views
RS485 Node/Cable Testing/Simulation
I am designing a system using RS485. There will be >100 nodes on a bus, each with input and output connectors, separated by ~1m.
In order to determine the signal quality at various speeds, I would ...
- 618
3
votes
0
answers
565
views
RS485 Protocol Reverse Engineering & Replay Challenges
I'm trying to reverse engineer the RS485 protocol used by my home heater/AC.
This protocol handles communications between the wired remote control (WRC)/thermostat and the main heater/ac indoor unit (...
- 31
3
votes
0
answers
760
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 ...
- 15k
3
votes
0
answers
202
views
RFI protection for a stepper motor controller
I'm building a remote tuning device for a magnetic loop antenna. It will use a stepper motor to turn the shaft on the mag loop's variable capacitor. The electronics will consist primarily of a ...
- 131
3
votes
0
answers
40
views
Implications of using a 2C-#18 twisted shield pair nec type cmr cable for RS-485
The cable will be passing modbus and another equal cable will be used for loadshare. The total cable distance will be about 100ft. Its catalog number E2032S.
I notice other threads related to CAT5, ...
2
votes
0
answers
34
views
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 ...
- 21
2
votes
2
answers
244
views
Reason to have MSB in a serial communication always high
I'm working on a code (written by other people) that uses a custom protocol to transmit data over RS485 in 8-bit packets.
For some reason, the protocol is built so that every 8 bits transmitted are ...
- 315
2
votes
0
answers
429
views
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 ...
- 415
2
votes
0
answers
221
views
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 ...
- 31
2
votes
1
answer
105
views
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 ...
- 6,024
2
votes
2
answers
905
views
SPI with differential line drivers, and star configuration problem
Folks I am helping to design a circuit for a group that uses the odrive motor driver board. The odrive drives two brushless motors and the MCU uses SPI to connect to motor encoders. People using the ...
- 81
2
votes
0
answers
227
views
RS485 registers for calculating total power consumption (kwh)
I have an energy meter (OHIO A2000) which has been now discontinued by the manufacturer. Anyway, I'm following the manual for extracting energy parameters through Modbus RS485 communication. I'm ...
- 21
2
votes
0
answers
1k
views
RS485 ground noise problem
I'm using the USB FTDI dongle to convert USB to RS485, half duplex, 3 wires (A+, B-, GND) with 115200 baud rate.
I'm working with controller of NXP (K64) and I'm experiencing random tx enables on the ...
- 193
2
votes
1
answer
258
views
Relay+SMPS = Noise in RS-485 bus
I designed a board with a microcontroller (Atmega328), 3 relays and a RS485 transceiver. The relays control SMPS LED drivers (Meanwell LPF series). The system consists of 10 boards, each one ...
- 21
2
votes
1
answer
577
views
Cable shielding groundloop
I am trying to connect a encoder to a motor controller which runs very close to the motor that it controls (30+ amps). Due to the risk of high EMI of the motor inducing on the encoder signals, we send ...
- 21