24 V nonstop even upon power failure - application note
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24 V nonstop – even upon power failure The right UPS system for every application – summary of advantages and disadvantages A reliable power supply is essential for guaranteeing the productivity of automated plants and machines. PLCs, sensors and actuators are usually provided with 24 V DC from a switched-mode power supply. Modern power supply units such as SITOP offer a maximum degree of security for the supply. However, they are not invulnerable to longer power supply failures. Critical applications therefore require upgrading to an uninterruptible power supply. But which UPS system is the right one, and what must be considered when dimensioning?

Application Note | 24 V nonstop – even upon power failure The right solution for every application In order to provide protection against power failure, an uninterruptible power supply can be used on the AC or DC side. The advantage of an AC UPS is that it provides buffering of all electrical consumers, e.g. also of AC drives. However, an AC UPS is more expensive than a DC UPS. If it is permissible with the application to only buffer the 24 V side in the event of a power failure, a DC UPS is quite definitely the more economical solution. On the one hand, the powers required are usually...

Application Note | 24 V nonstop – even upon power failure Bridging brief power failures The energy storage makes the difference When power supply conditions are unstable, for example in low-meshed network infrastructures, brief power failures may occur occasionally or even frequently as a result load transfers in the network, for example. Problems following such interruptions with non-buffered power supplies are the long ramp-up times and initialization of the automation system or involved drives. It is already possible to significantly increase the plant availability by using a buffer...

Application Note | 24 V nonstop - even upon power failure Lithium based batteries with longer lifetime, even at high temperatures Batteries using lithium, such as lithium iron phosphate (LiFePO4), bring together high temperature resilience and long lifetime. At 40°C, the lithium batteries are rated for 9 years, where traditional lead-acid batteries are rated for only 1 year. This dramatic difference makes the amortization of the valuable lithium technology possible over just a few years. Table 1: Service life and ambient temperature range of SHOP UPS1100 battery modules How supercaps work...

Application Note | 24 V nonstop - even upon power failure Charging times Specifications at rated input voltage and ambient temperature *25t funless otherwise specified) Table 2: Check in the table Buffering and charging times SITOP UPS500 TIA Selection Tool - convenient selection guide for power supply and DC UPS The selection with the 24 V consumer view in the TIA Selection Tool is more convenient and detailed than the manual selection, especially for the more demanding dimensioning of a DC UPS with batteries. The selection guide offers the possible DC UPS solutions with a few mouse...

Application Note | 24 V nonstop – even upon power failure How is the DC UPS integrated into the plant? The automation system must be informed about the status of the DC UPS so that it can respond correctly to the situation. Communication takes place via digital outputs, USB or Ethernet/PROFINET interfaces. DC UPS SITOP UPS500 (with ultracaps) Digital outputs SITOP Manager Digital outputs SITOP UPS1600 (with battery modules) Industr. Ethernet/ Profinet Engineering tool SITOP Manager STEP 7, TIA Portal Table 3: A free engineering tool is available for the DC UPS with interface and controller...

Application Note | 24 V nonstop – even upon power failure Parameters can be conveniently assigned via the SITOP Manager. Now with Version V1.1, all SITOP devices with USB or PN/IE communication can be configured and diagnosed. Figure 5: Backing up a 24 V automation computer with communication via USB SITOP Manager runs on Windows 7 and 10 and offers: • Online- and Offline-Engineering • Commissioning and continuous monitoring • Monitoring and controlled shutdown of multiple PCs in the event of a power failure, for example, by starting batch files and closing software applications • Online...

Application Note | 24 V nonstop – even upon power failure In addition, all device parameters can be read, for example, end-of-charge voltage, rated capacity, permissible temperature range, article number, serial number and version number. SITOP UPS with PROFINET on process control systems A free UPS1600 library with software blocks and faceplates is also available for the SIMATIC PCS 7 process control system. Automatic information about operating status messages such as power failure (buffer mode) or maintenance demanded as well as preventive battery replacement increase availability of the...