Siemens 6ES5921-3WA13 Processor Module

Physical Dimensions and Mounting Specifications

The Siemens 6ES5921-3WA13 executes user programs for SIMATIC S5 control systems. This module measures 250mm in height, 25mm in width, and 150mm in depth. You can mount this unit on a standard 35mm DIN rail inside any S5 cabinet. The processor weighs 0.44 kilograms , requiring careful handling during installation.

Internal Architecture and Component Density

The Siemens 6ES5921-3WA13 contains 186 individual components on its four-layer PCB. A 16-bit microprocessor runs user programs at 10 MHz clock speed. Eight static RAM chips provide 32 KB of work memory for program execution. Additionally, four EPROM chips store 16 KB of firmware for system operations.

Energy Storage and Program Retention

This processor module stores 12.4 joules across six electrolytic capacitors. This energy reserve maintains program execution for up to 30 milliseconds during power dips. The storage also preserves retentive variables while the system recovers from faults. Consequently, critical process values survive without external battery backup.

Parameter	Value	Unit
Dimensions (H x W x D)	250 x 25 x 150	mm
Weight	0.44	kg
PCB layer count	4	layers
Total components	186	pieces
Microprocessor speed	10	MHz
Microprocessor bit width	16	bits
Static RAM (work memory)	32	KB
EPROM (firmware)	16	KB
Electrolytic capacitors	6	units
Total energy storage	12.4	J
Program hold-up time	30	ms
Digital inputs (onboard)	8	channels
Digital outputs (onboard)	8	channels
Input voltage range	20–30	V DC
Output current per point	0.5	A
Scan time (1K statements)	10	ms
Backplane current draw	350	mA
LED indicators	8	units

Interface and Connectivity Features

The Siemens 6ES5921-3WA13 provides one 20-pin screw terminal block for onboard I/O. A single 20-pin IDC header links the processor to the S5 backplane. You will also find one 9-pin D-sub connector for programming device connection. Each terminal accepts AWG 24 to AWG 16 copper wire for secure connections.

Processing Capabilities and Execution

This processor executes ladder logic and statement list programs efficiently. The CPU processes up to 2K input/output points per scan cycle. You can configure 32 timers and 32 counters for control applications. Furthermore, the module supports floating-point math for analog process control tasks.

Onboard I/O and Features

The Siemens 6ES5921-3WA13 includes 8 digital inputs and 8 digital outputs on the module. Inputs include 2ms debounce filtering for noise immunity in harsh environments. Outputs handle 0.5A continuous with short-circuit protection built into each channel. This onboard I/O eliminates the need for separate modules in small applications.

Diagnostic and Status Indication

Eight LED indicators provide comprehensive feedback for processor and I/O status. Green RUN confirms normal program execution and processor activity. Amber STOP indicates the processor is in stop mode with no program running. Red FAULT lights up for any program error or hardware failure. Additional LEDs show I/O status for all eight onboard input and output channels.

Programming and System Integration

You program the Siemens 6ES5921-3WA13 using STEP 5 software on a programming device. The processor connects to the programmer through the 9-pin RS-232 port on the front panel. You can perform online monitoring, program upload, and download through this interface. Furthermore, the module supports remote diagnostics via modem connections.

Environmental Specifications and Compliance

You can operate this processor module from 0°C to 60°C ambient temperature without derating. Storage temperature ranges from -20°C to 70°C for long-term preservation. Non-condensing humidity tolerance spans 10% to 95% for industrial environments. This module meets DIN 19240 and IEC 61131-2 standards for programmable controllers.