MTL4042 REPEATER POWER SUPPLY IIB 4/20mA, for 2-wire transmitters The MTL4042 provides a fully-floating dc supply for energising a conventional 2- wire 4/20mA transmitter located in a hazardous area, and repeats the current in another circuit to drive a safe-area load.

SPECIFICATION See also common specification, cable parameters and approvals Number of channels One Location of transmitter Zone 0, IIB, T4–6 hazardous area if suitably certified Div. 1, Group C, hazardous location Voltage available for transmitter and lines 18.0V minimum at 20mA Note: maximum open-circuit voltage is 28V Input and output signal range 4 to 20mA Over-/under-range 1.0mA to 21.5mA Safe-area circuit load resistance Conventional transmitters: 0 to 650Ω Safe-area circuit output resistance >1MΩ Safe-area circuit ripple <50µA peak-to-peak up to 80kHz Transfer accuracy at 20°C Better than 20µA Temperature drift <1µA/°C Response time Settles within 200µA of final value within 20ms LED indicator Green: one provided for power indication Power requirement, Vs 65mA at 24V dc 75mA at 20V dc 50mA at 35V dc Power dissipation within unit 1.2W at 24V with 20mA signal 1.4W at 35V Isolation 250V ac between safe- and hazardous-area circuits Safety description Terminals 2 to 5 28V, 150Ω, 187mA, Um = 250V rms or dc FM entity parameters Voc = 28V dc, Isc = 185.5mA, Ca = 0.39µF, La = 4.5mH