Siemens 6ES7138-7FN00-0AB0 fail-safe electronics module for ET200iSP, 8F-DI NAMUR Ex I. Rated SIL 3 and PLe, with ATEX Ex ib (ia Ga) IIC T4 Gb marking.
SIS fit and NAMUR diagnostics
Each of the eight digital inputs accepts NAMUR encoders or a single contact with a 10 kOhm parallel resistor. The module continuously monitors for wire-break (signal below 1.2 mA quiescent) and short-circuit (load under 150 ohms with a NAMUR sensor). Signal transition times are parameterizable from 0.7 ms to 16 ms both directions, allowing debounce to be tuned to the application without adding external timers. Diagnostic alarms are parameterizable; a group error (red SF LED) and readable diagnostics are standard. Isolation is tested at 350 V AC between shield and backplane bus, and 2830 V AC between backplane bus and I/O — adequate for galvanic separation in multi-drop hazardous area wiring.
Ex compliance and power
The module is approved for ATEX Ex ib [ia Ga] IIC T4 Gb, meaning it is intrinsically safe (ib) and can connect to ia-rated sensors (the Ga tag). It also carries mining approval I M2 Ex ib [ia Ma] I Mb. SIL 3 and PLe are confirmed from the same evidence, so the module can be used in a high-demand safety loop without additional external barriers. Typical power loss is 1.4 W; current consumption from the internal powerbus is 145 mA. The module draws up to 150 mA from L+. Power budget planners should account for the input supply voltage of 8 V DC sourced from the backplane. Shielded cable runs are specified up to 500 m, unshielded to 200 m.