Siemens 6ES5900-7AB21 Central Processing Unit

This central processing unit executes logic programs for SIMATIC S5 automation systems. It manages all I/O data and communication tasks within the rack. Therefore, this CPU delivers dependable control for mid-sized industrial applications.

Physical Dimensions and Weight Specifications

The Siemens 6ES5900-7AB21 occupies a single slot in the S5 rack. Its housing measures 233 mm in depth for backplane connectivity. The module weighs approximately 0.65 kg for straightforward installation. Consequently, technicians can mount this unit without special handling equipment.

Interface Types and Connectivity Options

The Siemens 6ES5900-7AB21 provides one RS-232 programming port on the front. A second RS-422 interface supports connection to remote operator panels. The front panel carries a 20-pin connector for external expansion modules. Hence, users can access the CPU with standard Siemens cables.

Component Count and Onboard Memory

This central processor contains one main board with a 16-bit microcontroller. The board includes 64 KB of RAM for user program execution. You will also find 128 KB of EPROM for non-volatile storage. An onboard lithium battery retains RAM data for up to 300 days.

Energy Storage and Power Consumption

The Siemens 6ES5900-7AB21 draws 200 mA from the 5V backplane supply. A lithium coin cell provides backup power for the RAM storage. This battery maintains program and data for 300 days without external power. Therefore, the CPU retains critical information during long maintenance shutdowns.

Processing Speed and Scan Cycle Performance

The processor executes 1.2 microseconds per bit logic instruction. It handles up to 512 digital I/O points within a single scan. Users can store up to 512 function blocks in the EPROM memory. This capacity supports moderate automation tasks for assembly lines and conveyors.