Associated System Components

There are many parallels between the loop components that must be assessed for intrinsic safety as well as

functional safety where in both situations the contribution of each part is considered in relation to the whole.

The MTLx54x module is a component in the signal path between safety-related actuators and safety-related

control systems.

The current to pressure converter, valve positioner, or other field device, must be suitable for the process and

have been assessed and verified for use in functional safety applications as well as its certification for hazardous

area mounting.

The safety system PLC shall have a current output with a normal operating range of 4-20mA but capable of

working over the extended range of 3 to 22mA for under- and over-range. Such controllers will normally also

include a readback facility to enable the detection of open or short circuits in the wiring.

The transmission of HART data is not considered as part of the safety function and is excluded from this analysis.