AB Micrologix MTTF and MTTFd

Hi Everyone,

I am running through a few excersises to teach myself how to calculate safety performance levels. To do this I need to obtain some data on mean time to failure (MTTF) and mean time to failure to danger (MTTFd). I am working through some designs using AB Micrologix 1000 and 1100, but I cannot seem to find this data for these PLCs. If anyone can point me in the right direction, that would be appreciated. (also ML1400 and ML 1500, I will be checking through these next). Thanks.

The only thing I can find is the usual life of the relay outputs. Nothing else in the user manuals. You may need to put a call into Rockwell for the information.

Hi Tharon,

Same thing I found. The AB people have not woken up over here yet, but I will place a call soon.

Thanks

found this 115449 - MicroLogix Relay Output Life Expectancy
i would assume that the relay output is the first thing to fail. but you know what assuming does

Relay is not the only thing that can fail. I will have to find out from AB. They may be not publishing to ensure people don't use their devices as part of a safety system.

Followup for anyone interested,
AB do not publish this information publicly, but will provide it on request.
I have requested......

is that a nice way of saying you had to pay them for it ?