I was looking for a TTL to RS485 convertor . I expected the TTL end to have Vcc/Gnd /Tx/Rx but I find in the module below it is DI/DE/R1/R0 . Google told me what those abbreviations are. So I am not sure if this is the right module ... ?
Thanks !
I was looking for a TTL to RS485 convertor . I expected the TTL end to have Vcc/Gnd /Tx/Rx but I find in the module below it is DI/DE/R1/R0 . Google told me what those abbreviations are. So I am not sure if this is the right module ... ?
Thanks !
have a look at https://circuitdigest.com/rs-485-modbus-serial-communication-with-arduino-as-master
RE and DE enable the receiver and transmitter - you usually connect them together
e.g. when transmitting set both HIGH when transmission complete set both LOW
there are TTL-RS485 modules which handle the transmit/receive switch for you e.g. XY-017 3.3v 5v 12v RS485 TO TTL RS485 which saves some coding
what host microcomputer are you planning to use? I would recommend one with hardware serial ports such as the Mega or ESP32
I also find a USB-RS485 dongle which plugs into a PC useful in debugging RS485 systems
Technically speaking the Vcc & GND belong to the other end.
These units also come with a terminator on all modules regardless of whether the module is in drive or receive mode. (It's R7 a 120R resistor between A & B)
First of all there should not be more than 1 terminator on a bus or at least the total combined resistance should be about 120R (if you have 2 that would be 60R which isn't all that bad, but with 4 of them it would come down to 30R which will cause a lot more current through the bus than the transceiver can deal with)
Choose another module with standard labels.
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