Questions tagged [rs485]
EIA RS-485 is a serial communication standard using differential signaling.
635
questions
0
votes
0
answers
15
views
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?
- 173
0
votes
3
answers
70
views
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 ...
- 832
1
vote
2
answers
122
views
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 ...
4
votes
2
answers
221
views
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/) ...
- 51
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
1
vote
1
answer
84
views
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
...
0
votes
0
answers
29
views
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 ...
- 21
7
votes
3
answers
637
views
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 ...
- 1,795
3
votes
1
answer
145
views
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 ...
- 175
3
votes
2
answers
325
views
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 - ...
- 51
0
votes
2
answers
79
views
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 ...
0
votes
0
answers
51
views
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 ...
- 11
2
votes
3
answers
265
views
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".
...
- 12.9k
1
vote
1
answer
181
views
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 ...
- 41
0
votes
2
answers
115
views
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 ...
- 335