| ??? 11/26/10 17:34 Read: times |
#179670 - Not required for 61508 Responding to: ???'s previous message |
An independant watchdog may be required for 61508, but I think talk of highly redundant systems is a digression. Watchdogs are specifically mentioned because many of the on-chip watchdogs circuit don't work if the chip oscillator is switched off, which you can do in some of the lowest power sleep modes. Some chips have a WDT that uses an independant silicon delay oscillator, but convincing a certification authority that it meets the requirements can be an uphill struggle. |
| Topic | Author | Date |
| dual watchdog timer | 01/01/70 00:00 | |
| Scope | 01/01/70 00:00 | |
| maybe wrong site for the question but !!!!!!!!!!!!!!! | 01/01/70 00:00 | |
| You still haven't said... | 01/01/70 00:00 | |
| WDT failure | 01/01/70 00:00 | |
| Dual oscillator | 01/01/70 00:00 | |
| Do you need high reliability? | 01/01/70 00:00 | |
| IEC61508 | 01/01/70 00:00 | |
| Supervisor with WDT | 01/01/70 00:00 | |
| Since you are considering an 805x ... | 01/01/70 00:00 | |
| If one watchdog fails... | 01/01/70 00:00 | |
| the 1232 is external ... remember? | 01/01/70 00:00 | |
| Yes; that was my point - I was agreeing with you! | 01/01/70 00:00 | |
| Sorry! I didn't follow. | 01/01/70 00:00 | |
| Highly Redundant Systems | 01/01/70 00:00 | |
| a bit off the topic, but | 01/01/70 00:00 | |
| it's a matter of statistical probability | 01/01/70 00:00 | |
| Not required for 61508 | 01/01/70 00:00 | |
taken care | 01/01/70 00:00 |