| ??? 01/20/10 06:00 Read: times |
#172607 - Jumping to conclusions Responding to: ???'s previous message |
Erik Malund said:
Erik said:differential-ADC has around 120-130dB. CMRR
when within specified range!!! which 20V is not. usually the CMRR spec only hold till Vin + Vcm is less than Vce Ap responsed: Ofcourse ,but it was for 400mV appearing at the ADC input . that is TOTALLY irrelevant. If you have 20V common mode 20V (+- 400mV) will appear at both inputs. Erik Below was the topic under discussion and NOT a direct connection . I take that the resistive divider is doing its job on both channels ? . Erik Malund said:
another way (which would, most likely increase noise) would be divide the inputs in half and feed to a differential op amp running at +-15V Erik |
| Topic | Author | Date |
| Isolating xducer | 01/01/70 00:00 | |
| not even a way | 01/01/70 00:00 | |
| noise | 01/01/70 00:00 | |
| I wouldn't do that... | 01/01/70 00:00 | |
| agree | 01/01/70 00:00 | |
| when within specified range!!! | 01/01/70 00:00 | |
| why 8V or 20V | 01/01/70 00:00 | |
| no specs violated | 01/01/70 00:00 | |
| that is TOTALLY irrelevant | 01/01/70 00:00 | |
| Jumping to conclusions | 01/01/70 00:00 | |
| AC modulating the bridge excitation voltage? | 01/01/70 00:00 | |
modulating the excitation | 01/01/70 00:00 | |
| make it simple at start | 01/01/70 00:00 | |
| making it | 01/01/70 00:00 | |
| o, i see... | 01/01/70 00:00 | |
| from my experience with loadcells ... | 01/01/70 00:00 | |
| what is exactly "xducer" ? | 01/01/70 00:00 | |
| Offsetting a signal | 01/01/70 00:00 | |
| Yes but...? | 01/01/70 00:00 | |
| Error analysis and budget | 01/01/70 00:00 | |
| Common Mode suppression | 01/01/70 00:00 |