In intrinsically safe applications, it is sometimes necessary to separate sections of circuitry by resistors which limit current under fault conditions. The circuit shown provides an accurate analogue output with effectively zero output impedance, despite having resistors in series with the output. which is independent of RA and RB.
The values of RA and RB should be chosen to achieve the desired current limiting, but note that a proportion of the voltage given at the op-amp output will be dropped across these resistors. Any type of op amp would be suitable.