Hi,
I have a KC868-Server module, and a few Temperature and Humidity Sensors (XY-MD01). Everything works find when connection cable is short or when there is only one sensor connected via long cable ( a few meters).
However when I connection more that one sensors via long cable, sensors either do not work at all or some of them work time to time.
Any ideas?
Thank you in advance!
is this sensor use by RS485 interface?
Yes, the sensor is working on RS485 interface, and works well when only one connected or when more but with short cable length.
you can use CAT5 cable. how long distance your board can't work?
do you use KC868-Server conenct with only one RS485 sensor?
I use CAT6 cable, the cable length is different. I have 7 sensor in a house, and cable length can be up to 15 meter but in most cases less. Yes only sensors are connected to orange input on KC868-Server.
you ask you, when your problem whether test by only one sensor? do you understand me?
1 sensor connected to RS485 - everything works fine, cable length does not matter
2 or more sensors connected with short cable length - everything works well
2 or more sensors connected with long cable length - does not work on values can be read on rare cases
The last RS485 "SLAVE" device needs to be connected in parallel with a 120 ohm terminal resistor on the bus, do you have added it?
thank you for the advice, I forgot to put termination resistors to the both ends. Now it works, however reading is not stable, pretty often it returns CRC Error
any idea?
check your wire, you can test with short wire distance, whether work well, or only error in long distance.