ekachaiz

Hi, I've tried to disconnect the cable and tested camera one by one. They seem ok for a while but the same problem comes back after a few hours. (able to pan and tilt but zoom). I've read somewhere stating that there must be a termination at the end of the control line. This can be done by connecting 120ohms resistor accross +RS485 and -RS485. This is to prevent signal from bouncing back or something.. I'm not quite sure about that. Does anybody has any idea?? ?

Hi guys, I'm kinda new to this forum and i guess there're quite a number of experience CCTV installers here that could give me an advice and comment on a CCTV project that i'm working on. This is kind of my very first CCTV insallation project and i have very little experience on it so any advice would be a great help to me. Currently I've installed 28 speed dome cameras in this site and everything seems to work well except that there's a problem on the controlling part. I'm able to control the movement of every cameras but not zooming on some of them. The wierd thing is that, this problem seem to occur randomly. The way I solve this problem is to power off the camera that unable to zoom and turn it back on again but after sometime the problem would come back again. Further more, this problem is not just happen on certain camera but almost everyone of them. So now and then i have to walk to the camera that has zooming problem and reset it. Does anyone here has any idea what's going on? Link for the plan draw http://uk.pg.photos.yahoo.com/ph/ekachaiz/detail?.dir=2bdc&.dnm=7fe5.jpg&.src=ph