Advantages and Disadvantages of QMR PLC Over TMR PLC


Thread Starter


We are in process of indenting a PLC. As far as my knowledge true TMR configuration is being provided by Triconex only and to some extent ABB Plant Gaurd. Can we ask for bids from QMR vendors in addition to TMP vendors keeping in view the safety and reliability of the plant in view? What are the advantages and disadvantages of QMR PLC over TMR? Suggestions and feedbacks are welcome.


First of all I would like to inform you, the TMR Architecture is not only provided by Triconix there are some more vendors providing [it] and also if you want fully TMR configuration you have to go for ICS Triplex but I believe ICS is [more] costly then triconiex.

Major QMR vendor are HIMA and Honeywell and difference between both architecture are below TMR (2oo3) ( TMR had been popular system before the self-diagnostic techniques were developed)

Advantage OF TMR
* Proven system in safety market and created the myth that SIS = TMR
* System is fast
* Software User friendly.

Disadvantage of TMR
* High cost, high speed,
* It’s controlled by majority voting system and older technology (1980’s)
* Common cause failure rate is high
* Big Hardware size needs more cabinet.
* More hardware is use it may cause higher probability of failure.

About QMR system
all the QMR system is only the CPU is Quad Modular redundanct and IO card are single only.

And you can think about VMR system and 1oo2DR Systems in the biding. which may help you to understand about all the safety player in the market.