Questions tagged [rs485]
EIA RS-485 is a serial communication standard using differential signaling.
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Modbus receiving same message as sent
I am having a problem when communicating with a Modbus slave.
I have made a circuit with the translator shown in the picture. UART2_RXD and ...
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RS485 not working
I want to send data between different Arduinos distributed in different places:
Something like this: https://forum.arduino.cc/t/arduino-master-slave-communication-using-rs485-and-modbus-protocol/...
user337746
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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 ...
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How to reduce noise on RS485 line?
The above picture is the output of a MAX485 IC, which is an RS485 transceiver. When the Cable comes near an AC power line, this kind of noise adds up. Without the presence of the AC main line, its ...
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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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