New answers tagged rs485
5
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RS485 constant chip failure
Note that the isolation in the master is unnecessary. I'm not sure if the master's design is in your control or not. But, since both the master and the slave use the same power supply, there's no ...
10
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Accepted
RS485 constant chip failure
Of course it does not work, the slave and master are properly designed themselves, but as a system, you have two RS-485 transceivers that are fully isolated from each other trying to communicate ...
- 164k
1
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STM32 Multimaster / Multislave RS485 implementation with manual flow controll
Make your live easy! I would drop the idea of using the physical line for communicating the 'bus-busy-state'.
Assuming your setup is static, i would assing one of the masters as 'root-master' via e.g. ...
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2
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Accepted
STM32 Multimaster / Multislave RS485 implementation with manual flow controll
I spent a bunch of time trying to understand your bus state machine in the function busDrvUpdate() and controlled by the variable ...
- 176k
1
vote
Accepted
Should the 120 ohm termination resistor in a RS-485 transmitter circuit for DMX be infront of the surge protection resistors or not?
I would place it here:
That way you still get current limiting, without the rest of the bus 'seeing' something other than 120Ω. You could place a more ESD tolerant 120Ω resistor with a higher power ...
- 87.1k
2
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2 Master & 1 Slave communication over RS485 Bus line
Whether you're using a protocol like Modbus-RTU or similar, master/slave communication goes like this:
Master sends a command
The bus is silent while slave executes the command
Slave sends a reply
...
- 80.3k
0
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2 Master & 1 Slave communication over RS485 Bus line
Multi-master communication channels are notoriously difficult to get right, due to bus contention (collisions). Take a look at what the old 10BASE-2 over coax had to implement, with the help of a ...
- 42.1k
1
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Cable selection and wiring for RS485 communication
Consider the basics of what you are attempting to do. First and foremost is to create a reliable data link over cables. Right away this suggests using a twisted pair which provides consistant physical ...
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