Modbus communication problems when using other RS485 chip


Thread Starter


Still an armature here.

I'm currently using the M-system 53U energy meter with Modbus communication. I'm able to communicate with the meter using an mbed microcontroller NXP LPC1768 via 3.3V RS485(SIPEX SP485CS 9442) that i built. When i switch over to the MikroElektronika RS485 Click 3.3V board, i did not receive any reply from the meter.

Anyone has any idea why?
Check the "RS485 Click 3.3V" board schematics.
pin "TX" is Receiver Output
pin "RX" is Driver Input
Wiring is OK? between the NXP processor.

Good luck!
Shige Habara

John Waalkes

I've got a Mikro board with an add-on 485 board for it as well. What chip are you set up for (I'm developing on Atmels). Can you post the bit of code your are using for your RS-485 connection?