| ??? 02/08/08 07:41 Read: times |
#150449 - OK, bending it in neon --- Absolutely Responding to: ???'s previous message |
Erik Malund said:
if you have a choke in the 24V return which is what I have commented on you DO have two different grounds.. A choke in the return of the 24V supply will make the remote gnd 'dance' relative to the local gnd. This 'dance' will make the 232 inputs 'dance' by the same amount as the gnd 'dance'. Thus your 232 inputs will be infected by the same amount of variance that the choke eliminates. Either end will output 232 signals relative to it's ground, the other end will see it relative to it's ground. So, as far as I'm concerned if you have a choke in the supply return between two units, you can not communicate single ended between them. That I would never communicate single ended over any significant distance is another story. Erik I am just powering the sensor from my unit (control Box) and let it do what it want , it has contactors to control its process . I have a concern by which I want to make sure the power supply doesnt get corrupted , or the noise level dosent get raised as I send it that far out from my control box.
-------| |---------
SENSOR |-----------------VCC (24V)------------------|Control
|-----------------------GND------------------| Box
-------| |_________
Kai said to introduce a soft FB in both GND ans VCC according to the noise spectrum ,and an RC filter at sensor box. Your concern is right , I would use an opto for the feedback signals . But what if a choke isnt introduced will the GND level still remain the same my conductor is 17AWG but how to supress any undesired noise. AP |
| Topic | Author | Date |
| Powersupply issue | 01/01/70 00:00 | |
| Common mode noise! | 01/01/70 00:00 | |
| I run 24V for distances and ... | 01/01/70 00:00 | |
| using a choke in the ground line ... | 01/01/70 00:00 | |
| using a choke in the ground | 01/01/70 00:00 | |
| RS232 is 'pwer ground' referenced | 01/01/70 00:00 | |
| use 485 or opto --nop its not the case infact | 01/01/70 00:00 | |
| OK, bending it in neon | 01/01/70 00:00 | |
| OK, bending it in neon --- Absolutely | 01/01/70 00:00 | |
| the fallacy about a wire | 01/01/70 00:00 | |
| the fallacy about a wire ---What about Power | 01/01/70 00:00 | |
| so what? | 01/01/70 00:00 | |
so what? | 01/01/70 00:00 | |
| Differential mode chokes? | 01/01/70 00:00 | |
| Figure 3c ... | 01/01/70 00:00 | |
| Figure 3c ... | 01/01/70 00:00 | |
| Only an illustration... | 01/01/70 00:00 | |
| Only an illustration... | 01/01/70 00:00 |