CP 340, end-of-life reality
The 6ES7340-1AH02-0AE0: The temperature range — min. -40 °C, max. 70 °C — means it survives the nacelle environment on a cold winter night at hub height, where the controller cabinet sees ambient swings that kill a standard industrial module. No up-tower swaps if the CP 340 is already in the rack.
Sourcing a discontinued CP 340
Because this CP 340 is EOL hot, it is sourced through independent distribution against an RFQ. The BOM line that calls out 6ES7340-1AH02-0AE0 can be filled, but the procurement planner should budget for a last-time-buy or a qualified replacement. The module draws up to 165 mA from the 5 V backplane bus and dissipates 0.85 W max — the S7-300 rack power budget needs to account for this even if the rest of the slot configuration is low-power.
RS232C serial interface parameters
The single isolated RS232C interface runs at transmission rates from 2.4 kbit/s up to 19.2 kbit/s. With the 3964(R) protocol it hits the full 19.2 kbit/s; with the ASCII protocol the max drops to 9.6 kbit/s. Cable length is limited to 15 m — standard RS232 reach, but the isolation helps avoid ground loops in a mixed-voltage cabinet. The communications processor supports a 1 024 byte buffer for both ASCII and 3964(R) protocols, and the FB length in RAM is 2 700 bytes for data communication sending and receiving. No RK 512 protocol support, and customer-specific drivers are not reloadable.