The transmitter power supply units of the K and H systems from Pepperl+Fuchs have each been supplemented by two modules. They are designed for intrinsically safe applications up to SIL 3 in accordance with EN61508. An intrinsically safe signal circuit for SIL 3 can be set up with just one transmitter. This was previously possible with two separate inputs, both of which had to be monitored for redundancy reasons. In addition, internal diagnostic functions are signaled via an output and a red LED. The prescribed test intervals are extended for SIL 2 applications. The single-channel transmitter power supply units KCD2-STC-Ex.1ES and KFD2-STC4-Ex1.ES are 12.5 and 20 mm wide respectively and offer an active and passive 4 to 20 mA and 1 to 5 V output signal to the control level. Mounting on the standard rail (35 mm) with Power Rail enables information about the internal diagnostics with a failure signal. The HiC2025-ES and HiD2025ES devices were developed for the H system, in which the modules are mounted on pre-wired termination boards. The modules have a width of 12.5 and 18 mm respectively and are compatible with the termination boards of this system.