common ground, chasis ground & sheilding

hai all,

here i have 3 device that is sonar, camera and beacon which have pin arrangment like below:

Sonar
1) 24VDC
2) 0 VDC
3) RS232 Tx
4) RS232 Rx
5) Chasis ground
6) Sheild

camera
1) 0 VDC
2) 24 VDC
3) Video
4) Sheild

Beacon
1) 0 VDC
2) 24 VDC
3) RS232 Tx
4) RS 232 Rx

all of device above is connected in 1 power supply unit which AC~DC 110VAC/24VDC. For 24VDC from each device connected into power brass bar while 0VDC connected at common brass bar. Sheild of sonar i connect into common brass bar while sonar chasis is connected with earth of power supply. For camera video is connected into screen input while sheild connected with common brass bar. With follow what i done above is it camera video signal will be corupted by noise come from sonar chasis ground???? Did I need separate sonar 0VDC with camera 0VDC????


thanks,

regards
sasek