Siemens 6ES5942-7UA13 – Central Processing Unit for SIMATIC S5-115U

The Siemens 6ES5942-7UA13 serves as the main processor for small to medium S5 applications. This CPU module measures 250 mm in depth and 25 mm in width. It fits standard SIMATIC S5 rack slots without any modifications. The unit weighs 0.58 kg, making installation quick and straightforward.

Processor Architecture and Processing Speed

This central processing unit contains a 16-bit microprocessor running at 10 MHz. The Siemens 6ES5942-7UA13 executes 0.3 milliseconds per 1,000 bit operations. It processes 0.8 milliseconds per 1,000 word operations efficiently. The CPU handles up to 256 digital I/O points in a single configuration. It also manages up to 32 analog I/O channels without external expansion.

Memory Configuration and Storage Capacity

The CPU includes 8 kB of user program memory for application code. The Siemens 6ES5942-7UA13 also provides 2 kB of data memory for process values. A built-in battery-backed RAM retains critical data during power loss. A replaceable lithium battery maintains data for up to one year. The module supports up to 16 kB total memory with an optional expansion card.

Internal Architecture and Component Layout

The CPU contains three separate circuit boards inside its metal housing. One board holds the processor and memory, while another manages I/O scanning. The third board handles power regulation and backplane communication. The Siemens 6ES5942-7UA13 includes a 48-pin edge connector for rack interfacing. The module stores 150 µF of capacitance for power supply filtering.

Communication Ports and Status Indicators

You will find one programming port on the front panel of this CPU. This port uses an RS-232 interface for connection to programming devices. The Siemens 6ES5942-7UA13 includes LED indicators for power, run, and fault status. Six diagnostic LEDs show internal CPU and memory health conditions. The controller generates a watchdog alarm when program execution exceeds scan time limits.

Below is a complete summary of its technical specifications.

The Siemens 6ES5942-7UA13 replaces older CPUs in S5-115U systems directly. You do not need any special adapters or additional configuration tools. This CPU also supports step-by-step debugging for easier program testing. Consequently, it suits small packaging machines and simple conveyor control applications.