| Article number | 6ES7451-3AL00-0AE0 | 
|  | SIMATIC S7-300, FM 451 | 
| Supply voltage |  | 
| Rated value (DC) | 24 V | 
| Input current |  | 
| Current consumption, typ. | 550 mA | 
| Encoder supply |  | 
| 5 V encoder supply |  | 
| ● 5 V | Yes | 
| ● Output current, max. | 210 mA | 
| ● Cable length, max. | 35 m; at max. 210 mA | 
| 24 V encoder supply |  | 
| ● 24 V | Yes | 
| ● Output current, max. | 300 mA | 
| ● Cable length, max. | 100 m; at max. 300 mA | 
| Absolute encoder (SSI) encoder supply |  | 
| ● Absolute encoder (SSI) | Yes | 
| ● Type of output voltage | 24 V DC | 
| ● Output current, max. | 300 mA | 
| ● Cable length, max. | 300 m; At max. 156 kbit/s | 
| Power loss |  | 
| Power loss, typ. | 3.6 W | 
| Digital inputs |  | 
| Number of digital inputs | 12; 4 per axis | 
| Functions | Reference cams, reversing cams, flying actual value setting, start/stop positioning | 
| Input voltage |  | 
| ● Rated value (DC) | 24 V | 
| ● for signal “0” | -30 to +5 V | 
| ● for signal “1” | +11 to +30V | 
| Input current |  | 
| ● for signal “0”, max. (permissible quiescent current) | 1.5 mA | 
| ● for signal “1”, typ. | 9 mA | 
| Digital outputs |  | 
| Number of digital outputs | 12; 4 per axis | 
| Functions | Rapid traverse, creep, run right, run left | 
| Short-circuit protection | Yes | 
| Output voltage |  | 
| ● for signal “1”, min. | UP -3 V | 
| Output current |  | 
| ● for signal “1” permissible range for 0 to 55 °C, max. | 600 mA; with UPmax | 
| ● for signal “0” residual current, max. | 0.5 mA | 
| Encoder |  | 
| Connectable encoders |  | 
| ● Incremental encoder (symmetrical) | Yes | 
| ● Incremental encoder (asymmetrical) | Yes | 
| ● Absolute encoder (SSI) | Yes | 
| Encoder signals, incremental encoder (symmetrical) |  | 
| ● Trace mark signals | A, notA, B, notB | 
| ● Zero mark signal | N, notN | 
| ● Input voltage | 5 V difference signal (phys. RS 422) | 
| ● Input frequency, max. | 1 MHz | 
| Encoder signals, incremental encoder (asymmetrical) |  | 
| ● Trace mark signals | A, B | 
| ● Zero mark signal | N | 
| ● Input voltage | 24 V | 
| ● Input frequency, max. | 50 kHz; for 25 m cable length, 25 kHz for 100 m cable length | 
| ● Cable length, shielded, max. | 100 m | 
| Encoder signals, absolute encoder (SSI) |  | 
| ● Input signal | 5 V difference signal (phys. RS 422) | 
| ● Data signal | DATA, notDATA | 
| ● Clock signal | CL, notCL | 
| ● Telegram length, parameterizable | 13 or 25 bit serial | 
| ● Clock frequency, max. | 1.25 MHz | 
| ● Gray code | 1 | 
| ● Cable length, shielded, max. | 300 m; At max. 156 kbit/s | 
| Potential separation |  | 
| Potential separation digital inputs |  | 
| ● Potential separation digital inputs | Yes | 
| Potential separation digital outputs |  | 
| ● Potential separation digital outputs | Yes | 
| Ambient conditions |  | 
| Ambient temperature during operation |  | 
| ● min. | 0 °C | 
| ● max. | 55 °C | 
| Ambient temperature during storage/transportation |  | 
| ● min. | -40 °C | 
| ● max. | 70 °C | 
| connection method / header |  | 
| required front connector | 1x 48-pin | 
| Dimensions |  | 
| Width | 50 mm | 
| Height | 290 mm | 
| Depth | 210 mm | 
| Weights |  | 
| Weight, approx. | 1 300 g |