| ??? 08/16/11 13:00 Read: times |
#183377 - capacitor Responding to: ???'s previous message |
Kai Klaas said:
Friends of mine failed the CE test because of this! Thank you very much... I don't understand why there is no information about the cap in AM1D-0505SZ DC/DC convertor datasheet... and do you know how to obtain the value for this capacitor? In the Traco datasheet, it is always 470pF/2kV and it is also between Vin+ and Vout+. You suggest 10nF so I am not sure. I have 1nF/2kV 1812 available, so can I use this one? Kai Klaas said:
But make no mistake, proper surge protection needs the use of screened cables with the cable screen connected to protection earth at all ends. To avoid hum loops signal ground must not be connected to earth directly, but via 10nF/1kV cap, where the cable enters the chassis and the cable screen is connected to protection earth. It's also important to have low ohmic paths in the signal grounds between the RS485 partners. So, the inserting of these dozens of 100R resistors in the signal grounds as in your scheme is no good idea. I will have to have a think about it. But first, I will remove the 100R resistor as you suggest and insert the capacitor between the earth GND and signal GND. As I mentioned, I have 1nF/2kV available. Is it OK for this purpose? Thanks... Regards |
| Topic | Author | Date |
| Problem with RS232/RS485 converter... | 01/01/70 00:00 | |
| More info please | 01/01/70 00:00 | |
| probably | 01/01/70 00:00 | |
| more info... | 01/01/70 00:00 | |
| yes,i think | 01/01/70 00:00 | |
| input impedance | 01/01/70 00:00 | |
| i'm wrong | 01/01/70 00:00 | |
| what is the right value? | 01/01/70 00:00 | |
| did You tryed capacitor? | 01/01/70 00:00 | |
| thanks... | 01/01/70 00:00 | |
| it works...! | 01/01/70 00:00 | |
| congrats | 01/01/70 00:00 | |
| shape | 01/01/70 00:00 | |
| dont | 01/01/70 00:00 | |
| It is OK. | 01/01/70 00:00 | |
| Hints... | 01/01/70 00:00 | |
| schema | 01/01/70 00:00 | |
| Repair... | 01/01/70 00:00 | |
| transils... | 01/01/70 00:00 | |
| RS485 | 01/01/70 00:00 | |
| Sample Schematic | 01/01/70 00:00 | |
| Thank you very much for the schema... | 01/01/70 00:00 | |
| AVX varistors... | 01/01/70 00:00 | |
| capacitor | 01/01/70 00:00 | |
| capacitors... | 01/01/70 00:00 | |
| GNDs | 01/01/70 00:00 | |
| 1992 | 01/01/70 00:00 | |
| Thanks... | 01/01/70 00:00 | |
Links... | 01/01/70 00:00 |