Diagnostics and output behavior
The 6ES7135-4MB02-0AB0: Wire-break detection per channel, configurable enable/disable. Group diagnostics can flag a SF (red) LED or be suppressed. That means you can isolate a channel fault without taking down the whole station — useful on coolant-level or flow loops where one probe drops. Response to CPU/master STOP is selectable: de-energize the output current, substitute a value, or keep last value. Set this in the hardware config to match fail-safe requirements for your loop. Cycle time across all channels is 0.5 ms max, good for moderately fast process updates. Current output drives loads up to 500 Ω (resistive). For inductive loads up to 1 mH, expect a settling time of 0.5 ms. Resolution with overrange is 16 bit including sign.
Isolation and wiring
Galvanic isolation between channels and backplane bus, and between channels and load voltage L+. Tested at 500 V DC. No isolation between the two channels themselves — something to note if you need independent loop supplies per channel. Output circuit is two-wire connection only (four-wire not supported). Supply voltage is 24 V DC with reverse polarity protection. Maximum cable length: 200 m shielded (100 m if settling time < 2 ms).