Siemens 6ES5256-3AA21 VISRAM 256 Video Module

The 6ES5256-3AA21 provides video display capabilities for SIMATIC S5 systems. This module stores screen images and graphics data for operator displays. It connects directly to the S5 backplane for fast data transfer.

Key Technical Specifications

Parameter	Value
Video Memory	256 KB (VISRAM)
Display Resolution	640 x 480 pixels
Color Depth	16 colors (4-bit)
Refresh Rate	60 Hz (non-interlaced)
Video Output	9-pin VGA (analog RGB)
Supply Voltage	5V DC from backplane
Power Consumption	8 W maximum
Board Dimensions	23.0 cm x 14.0 cm x 3.5 cm
Weight	0.35 kg (0.77 lbs)
Component Count	94 discrete components
Energy Storage	1000 µF bulk capacitance
Operating Temperature	0°C to 60°C

Physical Dimensions and Component Layout

This board measures 23.0 cm in length and 14.0 cm in width. Its total height reaches 3.5 cm including the VGA connector. 6ES5256-3AA21 weighs just 0.35 kg for easy rack installation. You will find 94 discrete components on a six-layer PCB.

Moreover, the board integrates a 1000 µF bulk capacitor for supply smoothing. This capacitor filters noise from the 5V backplane power. It also provides a 10 ms hold-up during momentary voltage drops.

Video Memory and Graphics Processing

The 256 KB VISRAM stores pixel data for an entire screen image. A dedicated graphics controller manages all display refresh operations. This controller frees the main CPU from video processing tasks. You can update individual screen areas without redrawing the whole display.

Display Interface and Resolution

A standard 9-pin VGA connector outputs analog RGB signals. This interface supports most CRT and early LCD monitors. The module delivers 640 x 480 pixel resolution at 60 Hz. Sixteen simultaneous colors appear from a palette of 256 possible shades.

Communication with CPU

The S5 backplane transfers screen data at high speed to the video module. You can send text, bar graphs, and simple graphics from the PLC program. A set of special function blocks simplifies screen creation. LED indicators show video sync status and module health.

Typical Application Scenarios

You can deploy 6ES5256-3AA21 in SIMATIC S5 systems requiring visual operator displays. It also works well for process monitoring and machine status panels. This module shows production data, alarm lists, and system diagnostics on a monitor. Its 256KB memory suits text-based and simple graphic displays.