Problem with USB communication

[zhenqiang]

Now we designed a control panel with usb HID interface,the panel sent heartbeat message every 5 second.
There are mechanical encoders in this panel,the encoder output such as $g*i message when rotate the encoder cap,and the heartbeat message is $QWERWR* message.
The problem is sometimes when we rotate the encoder continuously,the panel may output R* occasionally,seems the end bits of the heartbeat message.
We have no idea with this problem?

 

[pjmelect]

I think that this is probably a rotary problem not a USB problem. A mechanical rotary encoder will occasionally send out the wrong code due to switch bounce. The only way to stop this is to either use a optical encoder or redesign the software to cope with errors from the rotary encoder.