What it is and what it does
The Siemens 3RS7020-2ET00 is a SIRIUS passive signal converter — one channel, 4...20 mA in and 4...20 mA out. It isolates and repeats a current loop signal without adding active power; the loop itself supplies the energy. Accuracy is 0.1 % with a temperature drift of 0.015 %/°C, so for a 20 mA span that's 20 µA error at 25 °C and another 3 µA per 10 °C shift. Settling time to 1 % of final value is 6 ms — fast enough for most process signals but not for high-speed valve positioning.
Mounting and wiring
Snap-on mounting on a 35 mm DIN rail, 6.2 mm wide — that's a single slice of a terminal-block footprint. Spring-loaded terminals accept 20...14 AWG solid or stranded (1 x 20...14 AWG per clamp). No special tool needed, but use a ferrule on stranded for best contact. Mounting position is any; clearance around the module is zero (0 mm upwards, forwards, backwards, downwards, sideways) — it can stack tight against adjacent devices.
Isolation and environment
Galvanic isolation between input and output (2-path design), no isolation between inputs or between outputs because there's only one channel. IP20 rated — fine inside a cabinet, not for wet or dusty locations. Operating temperature -25 to +60 °C, storage and transport -40 to +80 °C. Humidity 10...95 % RH non-condensing. The voltage ripple on the loop must stay under 5 mV for the rated accuracy.
Lifecycle and sourcing
Current production — no end-of-life notice on this code. The part is quoted to order; typical sourcing is against an RFQ for the exact BOM line. RoHS compliance date is March 25, 2015, so it meets the EU directive for new installations.