MTL5546Y Analogue Output, 1ch 4-20mA smart isolating driver + oc LFD. The MTL5546Y accepts a 4/20mA floating signal from a safe-area controller to drive a current/pressure converter (or any other load up to 800Ω) in a hazardous area. For HART valve positioners, the module also permits bi-directional transmission of digital communication signals. Process controllers with a readback facility can detect open or short circuits in the field wiring: if these occur, the current taken into the terminals drops to a preset level. The MTL4546C and the MTL5546Y are very similar to the MTL5546 except that they provide open circuit detection only(i.e. no short-circuit detection).