SITOP power supply concepts for SIMATIC PCS 7 process control system


The reliable 24V supply is an important factor for the high availability during plant operation.

To this end, SITOP offers 1-phase or 3-phase basic power supply units with different output power ratings of up to 1000 W and comprehensive certifications, such as ATEX or IECex, as well as MTBF values of more than 600,000 hours in 24-hour uninterrupted duty. These can be customized depending on the individual requirements and plant configuration–from redundant power supply, redundant power supply with selective monitoring of the 24V feeders all the way to redundant power supply with redundant buffering.

The SITOP library is available for preferred power supply concepts with blocks and faceplates for direct integration into SIMATIC PCS 7. The SW blocks in the SIMATIC S7 supply the faceplate on the user interface of the process control system with operating and diagnostics data, generate messages and ensure connection to the maintenance system of PCS 7.

This ensures constant transparency of the 24V supply in the control system. This means that PCS 7 users automatically receive information about operating status conditions (e.g. buffer mode), maintenance requirements (e.g. replacing batteries) and disturbances (e.g. short-circuit or overload in 24V circuits).

Critical plant states are recognized quickly to avoid costs due to failures. The result is a sustainable increase in plant availability.

The SITOP library supports the following power supply concepts:

Redundant power supply

The redundant configuration of the 24V supply offers additional protection from failure of the power supply units. The SITOP redundancy module continuously monitors two identical SITOP power supply units. If one unit fails, the other one automatically takes over the power supply. Signaling also takes place over signaling contacts that are evaluated in the control system.

Process picture in PCS 7

Integration in PCS 7 over digital inputs

Uninterruptible power supply

In the case of a power failure, the SITOP UPS1600 uninterruptible power supply can supply the automation system with 24V for several hours. Depending on the version of the DC UPS, it is integrated into the control system by means of digital I/Os or PROFINET. The intelligent battery management of the UPS1600 ensures optimum charging and continuous monitoring of the UPS1100 battery modules.

Process picture in PCS 7

Integration in PCS 7 over Ethernet

Selective monitoring of 24V feeders

The selectivity modules are the optimum enhancement for all 24V power supplies to distribute the load current to several feeders and to monitor it. The module detects an overload or short-circuit in one or several feeders and shuts them down as needed. This is ensured even on high-resistance lines and in the case of "creeping" short-circuits. The intact feeders continue to supply the SITOP selectivity modules with 24V on an interruption-free and reaction-free basis. Their signaling contact can be looped across several selectivity modules and can be evaluated as a common alarm in SIMATIC PCS 7.

Process picture in PCS 7

Integration in PCS 7 over digital inputs/outputs

Power supply system SITOP PSU8600

The SITOP PSU8600 power supply system consists of a PSU8600 basic unit with one or four selectively monitored DC outputs. The modular system with the innovative System Clip Link connection system allows for an individual combination of the power supply system without additional wiring. You can add up to four CNX8600 expansion modules (up to 16 additional DC outputs with selective monitoring) and a maximum of two BUF8600 buffer modules (buffer time of up to 20s at 40A). The order of the expansion modules and buffer modules is irrelevant in this case. They are integrated into the control system over PROFINET and provide comprehensive operating and diagnostic information such as output currents and voltages, overload or short-circuit.

Process picture in PCS 7

Integration in PCS 7 over Ethernet

The SITOP library supports

  • SIMATIC PCS 7 V9.0

  • SIMATIC PCS 7 V8.2

  • SIMATIC PCS 7 V8.1, V8.1 SP1

  • SIMATIC PCS 7 V8.0 SP2