What's the difference between TMR and Simplex in the speedtronic MKVI?

TMR is abbreviation of Triple Module Redundant. TMR is derived from the basic architecture with3 separate and independent Control Modules, Power supplies, and I/O Nets

Mark VI system with only R and C processors which is considered as 'simplex' system.

Sir, I did not work on Speedtronics but since your question was occupying me, here are some googling results for you, please surf and gather your answer.

http://control.com/thread/

http://iamechatronics.com/notes/automation-and-controls/513-introduction-to-speedtronic-mark-vi

In MKVI, Triple Module Redundant (TMR) is derived from the basic architecture with three completely separate and independent Control Modules, power supplies, and IONets. TMR architecture supports riding through a single point failure in the electronics and repair of the defective card or module while the process is running but in simplex this cannot be done while process is running. Another TMR feature is the ability to distinguish between field sensor faults and internal electronics faults. Diagnostics continuously monitor the3 sets of input electronics and alarms any discrepancies between them as an internal fault versus a sensor fault. In addition, all three main processors continue to execute the correct voted input data.

OK! Brother Waqar Ahmed, but As far as I know, C processor used only in Mark V system.

The archetectur of Mark VI (TCP) is completely different from Mark V. (^_^)

TMR is Triple Module Redundant which is clear from its name that you have triple redundant R,S and T controllers in case you lost one of them

mainly for protection inputs that can cause trips or shutdown

-Simplex means that the input signal will be only R or only S or only T with no redundancy and if you lose the simplex core that communicate this input to the other cores then there is no redundancy and you lose that input

mainly for monitoring inputs