What it is and what it does
The Siemens 3RK1901-1NP00 is an ASIsafe accessory — a 24 V DC supply module designed to sit alongside the K45F circuit breaker and power the sender of a safety light curtain. Its maximum current carrying capacity is 200 mA, which sets the limit for the light curtain's supply draw. This module is part of the ASIsafe safety system, used to deliver safe power to guarding components on automated lines.
What the ratings mean for fit
The 200 mA rating governs the maximum current the module can supply to the light curtain sender. If your safety light curtain draws more than 200 mA at 24 V DC, this module will not support it — you need a higher-capacity supply. The module is specific to the K45F circuit breaker form factor; it mounts alongside that breaker in the ASIsafe distribution block. Group code R711 and product group 3721 are internal Siemens classifications that help identify the part in their ordering system.