fix modbus timeout

kraftsensor.c

@@ -34,7 +34,7 @@ void do_kraftsensor(){
 
     /* read 2 16bit values and merge to 32bit signed integer */
     readReg(1,0,2);
-    if(wait_receive(2, m_data, 10)){
+    if(wait_receive(2, m_data, 100)){
         kraftsensor_valid = 0;
         printf("modbus error\n\r");
     }
@@ -73,8 +73,9 @@ uint8_t wait_receive(uint8_t len, uint16_t dest[], uint8_t timeout){
     while(!receiveOkay && breaker) { //wait for client response, time out after 1s
         breaker--;
         _delay_ms(1);
+        if(breaker==0)
+            return -1;
     }
-    printf("breaker: %d\n\r", breaker);
 
     if(receiveOkay) { //if this fails, there was either no response or a crc error
         if(rxbuffer[1]&0x80) { //client responded with an error code