rs485 link break when AC motor start

zafarkhan · Joined: 31 Oct 2007 Posts: 6

Hi
I made a counter with serial communication capabilities.
I have used pic16f877A and transiver is 75176. i have a laptop with usb to serial converter.
i have a problem that when a nearby motor starts the communication breaks.

regards
zafar

SherpaDoug · Joined: 07 Sep 2003 Posts: 1640 Location: Cape Cod Mass USA

First start by looking closely at grounding, shielding, and filtering. It would help a little if you could tell us the baud rate, wire type, motor type, message structure, and what exactly you mean by "communication breaks." Are you getting single bad bits, or whole strings of bytes getting garbled?
_________________
The search for better is endless. Instead simply find very good and get the job done.

arunb · Joined: 08 Sep 2003 Posts: 492 Location: India

Hi,

It is possible your USB converter is getting freezed up, I know this as it happens to my converter quite frequently (usually when a high voltage device like a relay or a stepper motor starts up).

One remedy is to keep the converter cable away from the high voltage device.

Hope this helps

thanks
arunb