Simple Modbus Slave RS485 Invalid CRC problem

Projects Networking, Protocols, and Devices
6

Hi this is my circuit :

and when i coennect it to my laptop via RS485 to USB Converter(com7) i have this result on Qmodbus software:

But if i Connect Arduino via USB Adapter to my laptop and choose USB Arduino (COM6) for Serial port
I have this result , in this case everything work fine and without any error or problem

i use same program for arduino in both case , This is the arduino code for test:
my modbus library for arduino is Modbus-Master-Slave-for-Arduino

/**
 *  Modbus slave example 3:
 *  The purpose of this example is to link a data array
 *  from the Arduino to an external device through RS485.
 *
 *  Recommended Modbus Master: QModbus
 *  http://qmodbus.sourceforge.net/
 */

#include <ModbusRtu.h>

// assign the Arduino pin that must be connected to RE-DE RS485 transceiver
#define TXEN	2 

// data array for modbus network sharing
uint16_t au16data[16] = {
  3, 1415, 9265, 4, 2, 7182, 28182, 8, 0, 0, 0, 0, 0, 0, 1, -1 };

/**
 *  Modbus object declaration
 *  u8id : node id = 0 for master, = 1..247 for slave
 *  u8serno : serial port (use 0 for Serial)
 *  u8txenpin : 0 for RS-232 and USB-FTDI 
 *               or any pin number > 1 for RS-485
 */
Modbus slave(1,0,TXEN); // this is slave @1 and RS-485

void setup() {
  slave.begin( 9600 ); // baud-rate at 9600
}

void loop() {
  slave.poll( au16data, 16 );
}

So What's the problem ?