What this module does in the S7-300 rack
The Siemens 6ES7334-0KE80-0AB0 is an SM 334 analog combo module for the S7-300 family — it packs 4 analog inputs and 2 analog outputs into a single 40 mm-wide slot, saving a slot compared to separate input and output modules. It handles Pt 100 resistance thermometers (climatic range only), 0-10 V voltage signals, and resistance measurements up to 10 kΩ, making it a fit for mixed-signal applications like temperature plus level or pressure transmitters on the same card.
The module draws 60 mA from the 5 V DC backplane bus and up to 80 mA from the 24 V DC supply L+ — budget that into your S7-300 power supply calculation so you don't brown out the rack. Input resistance on the 0-10 V channels is 100 kΩ, so a standard 4-20 mA loop with a 250 Ω burden resistor won't load the input — but this module does not accept current loops directly; you'd need an external shunt resistor. The analog outputs are short-circuit protected and can drive loads down to 2.5 kΩ with a capacitive load up to 1 µF — fine for driving a recorder or a remote display, but check the input impedance of whatever you're feeding.
Dimensions are 40 mm wide, 125 mm high, and 117 mm deep. It requires a 20-pin front connector (sold separately) for field wiring. The module supports 2-wire, 3-wire, and 4-wire RTD connections — for Pt 100, use the 4-wire connection to cancel lead resistance and get the best accuracy from the 12-bit ADC.