The Siemens 6ES7408-1TA01-0XA0 is a fan module for the SIMATIC S7-400 rack with 18 slots, running on 24 V DC. It pulls 0.9 A typical inrush at 24 V, so size your PSU for that spike — the steady-state draw is lower, but the inrush is what trips a marginal supply on power-up. The permissible DC range runs 19.2 V to 30 V, with the relay coil rated at exactly 24 V DC; if your panel bus dips below 19.2 V, the module drops out.
Electrical characteristics for the integrator
The module's max resistive load on the relay contacts is 200 mA — that's a signal-level output, not a power contact. If you're driving a contactor coil or a solenoid, buffer it through an interposing relay. The 24 V DC supply is isolated from the rack backplane; the inrush current of 0.9 A at 24 V is a cold-start transient, lasting maybe 20-50 ms. Your 24 V PSU should have at least 1.5 A headroom to avoid a brownout on the whole rack during power-on.